Merge tag 'trace-3.17' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:
 "This pull request has a lot of work done.  The main thing is the
  changes to the ftrace function callback infrastructure.  It's
  introducing a way to allow different functions to call directly
  different trampolines instead of all calling the same "mcount" one.

  The only user of this for now is the function graph tracer, which
  always had a different trampoline, but the function tracer trampoline
  was called and did basically nothing, and then the function graph
  tracer trampoline was called.  The difference now, is that the
  function graph tracer trampoline can be called directly if a function
  is only being traced by the function graph trampoline.  If function
  tracing is also happening on the same function, the old way is still
  done.

  The accounting for this takes up more memory when function graph
  tracing is activated, as it needs to keep track of which functions it
  uses.  I have a new way that wont take as much memory, but it's not
  ready yet for this merge window, and will have to wait for the next
  one.

  Another big change was the removal of the ftrace_start/stop() calls
  that were used by the suspend/resume code that stopped function
  tracing when entering into suspend and resume paths.  The stop of
  ftrace was done because there was some function that would crash the
  system if one called smp_processor_id()! The stop/start was a big
  hammer to solve the issue at the time, which was when ftrace was first
  introduced into Linux.  Now ftrace has better infrastructure to debug
  such issues, and I found the problem function and labeled it with
  "notrace" and function tracing can now safely be activated all the way
  down into the guts of suspend and resume

  Other changes include clean ups of uprobe code, clean up of the
  trace_seq() code, and other various small fixes and clean ups to
  ftrace and tracing"

* tag 'trace-3.17' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (57 commits)
  ftrace: Add warning if tramp hash does not match nr_trampolines
  ftrace: Fix trampoline hash update check on rec->flags
  ring-buffer: Use rb_page_size() instead of open coded head_page size
  ftrace: Rename ftrace_ops field from trampolines to nr_trampolines
  tracing: Convert local function_graph functions to static
  ftrace: Do not copy old hash when resetting
  tracing: let user specify tracing_thresh after selecting function_graph
  ring-buffer: Always run per-cpu ring buffer resize with schedule_work_on()
  tracing: Remove function_trace_stop and HAVE_FUNCTION_TRACE_MCOUNT_TEST
  s390/ftrace: remove check of obsolete variable function_trace_stop
  arm64, ftrace: Remove check of obsolete variable function_trace_stop
  Blackfin: ftrace: Remove check of obsolete variable function_trace_stop
  metag: ftrace: Remove check of obsolete variable function_trace_stop
  microblaze: ftrace: Remove check of obsolete variable function_trace_stop
  MIPS: ftrace: Remove check of obsolete variable function_trace_stop
  parisc: ftrace: Remove check of obsolete variable function_trace_stop
  sh: ftrace: Remove check of obsolete variable function_trace_stop
  sparc64,ftrace: Remove check of obsolete variable function_trace_stop
  tile: ftrace: Remove check of obsolete variable function_trace_stop
  ftrace: x86: Remove check of obsolete variable function_trace_stop
  ...

11 files changed, 932 insertions, 456 deletions

diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index d4409356f40d..a5da09c899dd 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -29,11 +29,6 @@ config HAVE_FUNCTION_GRAPH_FP_TEST
         help
           See Documentation/trace/ftrace-design.txt
 
-config HAVE_FUNCTION_TRACE_MCOUNT_TEST
-        bool
-        help
-          See Documentation/trace/ftrace-design.txt
-
 config HAVE_DYNAMIC_FTRACE
         bool
         help
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index 2611613f14f1..67d6369ddf83 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -28,6 +28,7 @@ obj-$(CONFIG_RING_BUFFER_BENCHMARK) += ring_buffer_benchmark.o
 
 obj-$(CONFIG_TRACING) += trace.o
 obj-$(CONFIG_TRACING) += trace_output.o
+obj-$(CONFIG_TRACING) += trace_seq.o
 obj-$(CONFIG_TRACING) += trace_stat.o
 obj-$(CONFIG_TRACING) += trace_printk.o
 obj-$(CONFIG_CONTEXT_SWITCH_TRACER) += trace_sched_switch.o
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index ac9d1dad630b..1654b12c891a 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -80,9 +80,6 @@ static struct ftrace_ops ftrace_list_end __read_mostly = {
 int ftrace_enabled __read_mostly;
 static int last_ftrace_enabled;
 
-/* Quick disabling of function tracer. */
-int function_trace_stop __read_mostly;
-
 /* Current function tracing op */
 struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
 /* What to set function_trace_op to */
@@ -1042,6 +1039,8 @@ static struct pid * const ftrace_swapper_pid = &init_struct_pid;
 
 #ifdef CONFIG_DYNAMIC_FTRACE
 
+static struct ftrace_ops *removed_ops;
+
 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
 # error Dynamic ftrace depends on MCOUNT_RECORD
 #endif
@@ -1304,25 +1303,15 @@ ftrace_hash_move(struct ftrace_ops *ops, int enable,
         struct ftrace_hash *new_hash;
         int size = src->count;
         int bits = 0;
-        int ret;
         int i;
 
         /*
-         * Remove the current set, update the hash and add
-         * them back.
-         */
-        ftrace_hash_rec_disable(ops, enable);
-
-        /*
          * If the new source is empty, just free dst and assign it
          * the empty_hash.
          */
         if (!src->count) {
-                free_ftrace_hash_rcu(*dst);
-                rcu_assign_pointer(*dst, EMPTY_HASH);
-                /* still need to update the function records */
-                ret = 0;
-                goto out;
+                new_hash = EMPTY_HASH;
+                goto update;
         }
 
         /*
@@ -1335,10 +1324,9 @@ ftrace_hash_move(struct ftrace_ops *ops, int enable,
         if (bits > FTRACE_HASH_MAX_BITS)
                 bits = FTRACE_HASH_MAX_BITS;
 
-        ret = -ENOMEM;
         new_hash = alloc_ftrace_hash(bits);
         if (!new_hash)
-                goto out;
+                return -ENOMEM;
 
         size = 1 << src->size_bits;
         for (i = 0; i < size; i++) {
@@ -1349,20 +1337,20 @@ ftrace_hash_move(struct ftrace_ops *ops, int enable,
                 }
         }
 
+update:
+        /*
+         * Remove the current set, update the hash and add
+         * them back.
+         */
+        ftrace_hash_rec_disable(ops, enable);
+
         old_hash = *dst;
         rcu_assign_pointer(*dst, new_hash);
         free_ftrace_hash_rcu(old_hash);
 
-        ret = 0;
- out:
-        /*
-         * Enable regardless of ret:
-         *  On success, we enable the new hash.
-         *  On failure, we re-enable the original hash.
-         */
         ftrace_hash_rec_enable(ops, enable);
 
-        return ret;
+        return 0;
 }
 
 /*
@@ -1492,6 +1480,53 @@ int ftrace_text_reserved(const void *start, const void *end)
         return (int)!!ret;
 }
 
+/* Test if ops registered to this rec needs regs */
+static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
+{
+        struct ftrace_ops *ops;
+        bool keep_regs = false;
+
+        for (ops = ftrace_ops_list;
+             ops != &ftrace_list_end; ops = ops->next) {
+                /* pass rec in as regs to have non-NULL val */
+                if (ftrace_ops_test(ops, rec->ip, rec)) {
+                        if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
+                                keep_regs = true;
+                                break;
+                        }
+                }
+        }
+
+        return  keep_regs;
+}
+
+static void ftrace_remove_tramp(struct ftrace_ops *ops,
+                                struct dyn_ftrace *rec)
+{
+        struct ftrace_func_entry *entry;
+
+        entry = ftrace_lookup_ip(ops->tramp_hash, rec->ip);
+        if (!entry)
+                return;
+
+        /*
+         * The tramp_hash entry will be removed at time
+         * of update.
+         */
+        ops->nr_trampolines--;
+        rec->flags &= ~FTRACE_FL_TRAMP;
+}
+
+static void ftrace_clear_tramps(struct dyn_ftrace *rec)
+{
+        struct ftrace_ops *op;
+
+        do_for_each_ftrace_op(op, ftrace_ops_list) {
+                if (op->nr_trampolines)
+                        ftrace_remove_tramp(op, rec);
+        } while_for_each_ftrace_op(op);
+}
+
 static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
                                      int filter_hash,
                                      bool inc)
@@ -1572,8 +1607,30 @@ static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
 
                 if (inc) {
                         rec->flags++;
-                        if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == FTRACE_REF_MAX))
+                        if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
                                 return;
+
+                        /*
+                         * If there's only a single callback registered to a
+                         * function, and the ops has a trampoline registered
+                         * for it, then we can call it directly.
+                         */
+                        if (ftrace_rec_count(rec) == 1 && ops->trampoline) {
+                                rec->flags |= FTRACE_FL_TRAMP;
+                                ops->nr_trampolines++;
+                        } else {
+                                /*
+                                 * If we are adding another function callback
+                                 * to this function, and the previous had a
+                                 * trampoline used, then we need to go back to
+                                 * the default trampoline.
+                                 */
+                                rec->flags &= ~FTRACE_FL_TRAMP;
+
+                                /* remove trampolines from any ops for this rec */
+                                ftrace_clear_tramps(rec);
+                        }
+
                         /*
                          * If any ops wants regs saved for this function
                          * then all ops will get saved regs.
@@ -1581,9 +1638,30 @@ static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
                         if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
                                 rec->flags |= FTRACE_FL_REGS;
                 } else {
-                        if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == 0))
+                        if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
                                 return;
                         rec->flags--;
+
+                        if (ops->trampoline && !ftrace_rec_count(rec))
+                                ftrace_remove_tramp(ops, rec);
+
+                        /*
+                         * If the rec had REGS enabled and the ops that is
+                         * being removed had REGS set, then see if there is
+                         * still any ops for this record that wants regs.
+                         * If not, we can stop recording them.
+                         */
+                        if (ftrace_rec_count(rec) > 0 &&
+                            rec->flags & FTRACE_FL_REGS &&
+                            ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
+                                if (!test_rec_ops_needs_regs(rec))
+                                        rec->flags &= ~FTRACE_FL_REGS;
+                        }
+
+                        /*
+                         * flags will be cleared in ftrace_check_record()
+                         * if rec count is zero.
+                         */
                 }
                 count++;
                 /* Shortcut, if we handled all records, we are done. */
@@ -1668,17 +1746,23 @@ static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
          * If we are disabling calls, then disable all records that
          * are enabled.
          */
-        if (enable && (rec->flags & ~FTRACE_FL_MASK))
+        if (enable && ftrace_rec_count(rec))
                 flag = FTRACE_FL_ENABLED;
 
         /*
-         * If enabling and the REGS flag does not match the REGS_EN, then
-         * do not ignore this record. Set flags to fail the compare against
-         * ENABLED.
+         * If enabling and the REGS flag does not match the REGS_EN, or
+         * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
+         * this record. Set flags to fail the compare against ENABLED.
          */
-        if (flag &&
-            (!(rec->flags & FTRACE_FL_REGS) != !(rec->flags & FTRACE_FL_REGS_EN)))
-                flag |= FTRACE_FL_REGS;
+        if (flag) {
+                if (!(rec->flags & FTRACE_FL_REGS) != 
+                    !(rec->flags & FTRACE_FL_REGS_EN))
+                        flag |= FTRACE_FL_REGS;
+
+                if (!(rec->flags & FTRACE_FL_TRAMP) != 
+                    !(rec->flags & FTRACE_FL_TRAMP_EN))
+                        flag |= FTRACE_FL_TRAMP;
+        }
 
         /* If the state of this record hasn't changed, then do nothing */
         if ((rec->flags & FTRACE_FL_ENABLED) == flag)
@@ -1696,6 +1780,12 @@ static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
                                 else
                                         rec->flags &= ~FTRACE_FL_REGS_EN;
                         }
+                        if (flag & FTRACE_FL_TRAMP) {
+                                if (rec->flags & FTRACE_FL_TRAMP)
+                                        rec->flags |= FTRACE_FL_TRAMP_EN;
+                                else
+                                        rec->flags &= ~FTRACE_FL_TRAMP_EN;
+                        }
                 }
 
                 /*
@@ -1704,7 +1794,7 @@ static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
                  * Otherwise,
                  *   return UPDATE_MODIFY_CALL to tell the caller to convert
                  *   from the save regs, to a non-save regs function or
-                 *   vice versa.
+                 *   vice versa, or from a trampoline call.
                  */
                 if (flag & FTRACE_FL_ENABLED)
                         return FTRACE_UPDATE_MAKE_CALL;
@@ -1714,7 +1804,7 @@ static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
 
         if (update) {
                 /* If there's no more users, clear all flags */
-                if (!(rec->flags & ~FTRACE_FL_MASK))
+                if (!ftrace_rec_count(rec))
                         rec->flags = 0;
                 else
                         /* Just disable the record (keep REGS state) */
@@ -1751,6 +1841,43 @@ int ftrace_test_record(struct dyn_ftrace *rec, int enable)
         return ftrace_check_record(rec, enable, 0);
 }
 
+static struct ftrace_ops *
+ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
+{
+        struct ftrace_ops *op;
+
+        /* Removed ops need to be tested first */
+        if (removed_ops && removed_ops->tramp_hash) {
+                if (ftrace_lookup_ip(removed_ops->tramp_hash, rec->ip))
+                        return removed_ops;
+        }
+
+        do_for_each_ftrace_op(op, ftrace_ops_list) {
+                if (!op->tramp_hash)
+                        continue;
+
+                if (ftrace_lookup_ip(op->tramp_hash, rec->ip))
+                        return op;
+
+        } while_for_each_ftrace_op(op);
+
+        return NULL;
+}
+
+static struct ftrace_ops *
+ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
+{
+        struct ftrace_ops *op;
+
+        do_for_each_ftrace_op(op, ftrace_ops_list) {
+                /* pass rec in as regs to have non-NULL val */
+                if (ftrace_ops_test(op, rec->ip, rec))
+                        return op;
+        } while_for_each_ftrace_op(op);
+
+        return NULL;
+}
+
 /**
  * ftrace_get_addr_new - Get the call address to set to
  * @rec:  The ftrace record descriptor
@@ -1763,6 +1890,20 @@ int ftrace_test_record(struct dyn_ftrace *rec, int enable)
  */
 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
 {
+        struct ftrace_ops *ops;
+
+        /* Trampolines take precedence over regs */
+        if (rec->flags & FTRACE_FL_TRAMP) {
+                ops = ftrace_find_tramp_ops_new(rec);
+                if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
+                        pr_warning("Bad trampoline accounting at: %p (%pS)\n",
+                                    (void *)rec->ip, (void *)rec->ip);
+                        /* Ftrace is shutting down, return anything */
+                        return (unsigned long)FTRACE_ADDR;
+                }
+                return ops->trampoline;
+        }
+
         if (rec->flags & FTRACE_FL_REGS)
                 return (unsigned long)FTRACE_REGS_ADDR;
         else
@@ -1781,6 +1922,20 @@ unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
  */
 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
 {
+        struct ftrace_ops *ops;
+
+        /* Trampolines take precedence over regs */
+        if (rec->flags & FTRACE_FL_TRAMP_EN) {
+                ops = ftrace_find_tramp_ops_curr(rec);
+                if (FTRACE_WARN_ON(!ops)) {
+                        pr_warning("Bad trampoline accounting at: %p (%pS)\n",
+                                    (void *)rec->ip, (void *)rec->ip);
+                        /* Ftrace is shutting down, return anything */
+                        return (unsigned long)FTRACE_ADDR;
+                }
+                return ops->trampoline;
+        }
+
         if (rec->flags & FTRACE_FL_REGS_EN)
                 return (unsigned long)FTRACE_REGS_ADDR;
         else
@@ -2023,6 +2178,89 @@ void __weak arch_ftrace_update_code(int command)
         ftrace_run_stop_machine(command);
 }
 
+static int ftrace_save_ops_tramp_hash(struct ftrace_ops *ops)
+{
+        struct ftrace_page *pg;
+        struct dyn_ftrace *rec;
+        int size, bits;
+        int ret;
+
+        size = ops->nr_trampolines;
+        bits = 0;
+        /*
+         * Make the hash size about 1/2 the # found
+         */
+        for (size /= 2; size; size >>= 1)
+                bits++;
+
+        ops->tramp_hash = alloc_ftrace_hash(bits);
+        /*
+         * TODO: a failed allocation is going to screw up
+         * the accounting of what needs to be modified
+         * and not. For now, we kill ftrace if we fail
+         * to allocate here. But there are ways around this,
+         * but that will take a little more work.
+         */
+        if (!ops->tramp_hash)
+                return -ENOMEM;
+
+        do_for_each_ftrace_rec(pg, rec) {
+                if (ftrace_rec_count(rec) == 1 &&
+                    ftrace_ops_test(ops, rec->ip, rec)) {
+
+                        /*
+                         * If another ops adds to a rec, the rec will
+                         * lose its trampoline and never get it back
+                         * until all ops are off of it.
+                         */
+                        if (!(rec->flags & FTRACE_FL_TRAMP))
+                                continue;
+
+                        /* This record had better have a trampoline */
+                        if (FTRACE_WARN_ON(!(rec->flags & FTRACE_FL_TRAMP_EN)))
+                                return -1;
+
+                        ret = add_hash_entry(ops->tramp_hash, rec->ip);
+                        if (ret < 0)
+                                return ret;
+                }
+        } while_for_each_ftrace_rec();
+
+        /* The number of recs in the hash must match nr_trampolines */
+        FTRACE_WARN_ON(ops->tramp_hash->count != ops->nr_trampolines);
+
+        return 0;
+}
+
+static int ftrace_save_tramp_hashes(void)
+{
+        struct ftrace_ops *op;
+        int ret;
+
+        /*
+         * Now that any trampoline is being used, we need to save the
+         * hashes for the ops that have them. This allows the mapping
+         * back from the record to the ops that has the trampoline to
+         * know what code is being replaced. Modifying code must always
+         * verify what it is changing.
+         */
+        do_for_each_ftrace_op(op, ftrace_ops_list) {
+
+                /* The tramp_hash is recreated each time. */
+                free_ftrace_hash(op->tramp_hash);
+                op->tramp_hash = NULL;
+
+                if (op->nr_trampolines) {
+                        ret = ftrace_save_ops_tramp_hash(op);
+                        if (ret)
+                                return ret;
+                }
+
+        } while_for_each_ftrace_op(op);
+
+        return 0;
+}
+
 static void ftrace_run_update_code(int command)
 {
         int ret;
@@ -2031,11 +2269,6 @@ static void ftrace_run_update_code(int command)
         FTRACE_WARN_ON(ret);
         if (ret)
                 return;
-        /*
-         * Do not call function tracer while we update the code.
-         * We are in stop machine.
-         */
-        function_trace_stop++;
 
         /*
          * By default we use stop_machine() to modify the code.
@@ -2045,15 +2278,15 @@ static void ftrace_run_update_code(int command)
          */
         arch_ftrace_update_code(command);
 
-        function_trace_stop--;
-
         ret = ftrace_arch_code_modify_post_process();
         FTRACE_WARN_ON(ret);
+
+        ret = ftrace_save_tramp_hashes();
+        FTRACE_WARN_ON(ret);
 }
 
 static ftrace_func_t saved_ftrace_func;
 static int ftrace_start_up;
-static int global_start_up;
 
 static void control_ops_free(struct ftrace_ops *ops)
 {
@@ -2117,8 +2350,7 @@ static int ftrace_shutdown(struct ftrace_ops *ops, int command)
 
         ftrace_hash_rec_disable(ops, 1);
 
-        if (!global_start_up)
-                ops->flags &= ~FTRACE_OPS_FL_ENABLED;
+        ops->flags &= ~FTRACE_OPS_FL_ENABLED;
 
         command |= FTRACE_UPDATE_CALLS;
 
@@ -2139,8 +2371,16 @@ static int ftrace_shutdown(struct ftrace_ops *ops, int command)
                 return 0;
         }
 
+        /*
+         * If the ops uses a trampoline, then it needs to be
+         * tested first on update.
+         */
+        removed_ops = ops;
+
         ftrace_run_update_code(command);
 
+        removed_ops = NULL;
+
         /*
          * Dynamic ops may be freed, we must make sure that all
          * callers are done before leaving this function.
@@ -2398,7 +2638,8 @@ ftrace_allocate_pages(unsigned long num_to_init)
         return start_pg;
 
  free_pages:
-        while (start_pg) {
+        pg = start_pg;
+        while (pg) {
                 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
                 free_pages((unsigned long)pg->records, order);
                 start_pg = pg->next;
@@ -2595,8 +2836,10 @@ static void *t_start(struct seq_file *m, loff_t *pos)
          * off, we can short cut and just print out that all
          * functions are enabled.
          */
-        if (iter->flags & FTRACE_ITER_FILTER &&
-            ftrace_hash_empty(ops->filter_hash)) {
+        if ((iter->flags & FTRACE_ITER_FILTER &&
+             ftrace_hash_empty(ops->filter_hash)) ||
+            (iter->flags & FTRACE_ITER_NOTRACE &&
+             ftrace_hash_empty(ops->notrace_hash))) {
                 if (*pos > 0)
                         return t_hash_start(m, pos);
                 iter->flags |= FTRACE_ITER_PRINTALL;
@@ -2641,7 +2884,10 @@ static int t_show(struct seq_file *m, void *v)
                 return t_hash_show(m, iter);
 
         if (iter->flags & FTRACE_ITER_PRINTALL) {
-                seq_printf(m, "#### all functions enabled ####\n");
+                if (iter->flags & FTRACE_ITER_NOTRACE)
+                        seq_printf(m, "#### no functions disabled ####\n");
+                else
+                        seq_printf(m, "#### all functions enabled ####\n");
                 return 0;
         }
 
@@ -2651,10 +2897,22 @@ static int t_show(struct seq_file *m, void *v)
                 return 0;
 
         seq_printf(m, "%ps", (void *)rec->ip);
-        if (iter->flags & FTRACE_ITER_ENABLED)
+        if (iter->flags & FTRACE_ITER_ENABLED) {
                 seq_printf(m, " (%ld)%s",
-                           rec->flags & ~FTRACE_FL_MASK,
-                           rec->flags & FTRACE_FL_REGS ? " R" : "");
+                           ftrace_rec_count(rec),
+                           rec->flags & FTRACE_FL_REGS ? " R" : "  ");
+                if (rec->flags & FTRACE_FL_TRAMP_EN) {
+                        struct ftrace_ops *ops;
+
+                        ops = ftrace_find_tramp_ops_curr(rec);
+                        if (ops && ops->trampoline)
+                                seq_printf(m, "\ttramp: %pS",
+                                           (void *)ops->trampoline);
+                        else
+                                seq_printf(m, "\ttramp: ERROR!");
+                }
+        }       
+
         seq_printf(m, "\n");
 
         return 0;
@@ -2702,13 +2960,6 @@ ftrace_enabled_open(struct inode *inode, struct file *file)
         return iter ? 0 : -ENOMEM;
 }
 
-static void ftrace_filter_reset(struct ftrace_hash *hash)
-{
-        mutex_lock(&ftrace_lock);
-        ftrace_hash_clear(hash);
-        mutex_unlock(&ftrace_lock);
-}
-
 /**
  * ftrace_regex_open - initialize function tracer filter files
  * @ops: The ftrace_ops that hold the hash filters
@@ -2758,7 +3009,13 @@ ftrace_regex_open(struct ftrace_ops *ops, int flag,
                 hash = ops->filter_hash;
 
         if (file->f_mode & FMODE_WRITE) {
-                iter->hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, hash);
+                const int size_bits = FTRACE_HASH_DEFAULT_BITS;
+
+                if (file->f_flags & O_TRUNC)
+                        iter->hash = alloc_ftrace_hash(size_bits);
+                else
+                        iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
+
                 if (!iter->hash) {
                         trace_parser_put(&iter->parser);
                         kfree(iter);
@@ -2767,10 +3024,6 @@ ftrace_regex_open(struct ftrace_ops *ops, int flag,
                 }
         }
 
-        if ((file->f_mode & FMODE_WRITE) &&
-            (file->f_flags & O_TRUNC))
-                ftrace_filter_reset(iter->hash);
-
         if (file->f_mode & FMODE_READ) {
                 iter->pg = ftrace_pages_start;
 
@@ -3471,14 +3724,16 @@ ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
         else
                 orig_hash = &ops->notrace_hash;
 
-        hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
+        if (reset)
+                hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
+        else
+                hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
+
         if (!hash) {
                 ret = -ENOMEM;
                 goto out_regex_unlock;
         }
 
-        if (reset)
-                ftrace_filter_reset(hash);
         if (buf && !ftrace_match_records(hash, buf, len)) {
                 ret = -EINVAL;
                 goto out_regex_unlock;
@@ -3630,6 +3885,7 @@ __setup("ftrace_filter=", set_ftrace_filter);
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
+static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
 static int ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer);
 
 static int __init set_graph_function(char *str)
@@ -3639,16 +3895,29 @@ static int __init set_graph_function(char *str)
 }
 __setup("ftrace_graph_filter=", set_graph_function);
 
-static void __init set_ftrace_early_graph(char *buf)
+static int __init set_graph_notrace_function(char *str)
+{
+        strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
+        return 1;
+}
+__setup("ftrace_graph_notrace=", set_graph_notrace_function);
+
+static void __init set_ftrace_early_graph(char *buf, int enable)
 {
         int ret;
         char *func;
+        unsigned long *table = ftrace_graph_funcs;
+        int *count = &ftrace_graph_count;
+
+        if (!enable) {
+                table = ftrace_graph_notrace_funcs;
+                count = &ftrace_graph_notrace_count;
+        }
 
         while (buf) {
                 func = strsep(&buf, ",");
                 /* we allow only one expression at a time */
-                ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
-                                      FTRACE_GRAPH_MAX_FUNCS, func);
+                ret = ftrace_set_func(table, count, FTRACE_GRAPH_MAX_FUNCS, func);
                 if (ret)
                         printk(KERN_DEBUG "ftrace: function %s not "
                                           "traceable\n", func);
@@ -3677,7 +3946,9 @@ static void __init set_ftrace_early_filters(void)
                 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
         if (ftrace_graph_buf[0])
-                set_ftrace_early_graph(ftrace_graph_buf);
+                set_ftrace_early_graph(ftrace_graph_buf, 1);
+        if (ftrace_graph_notrace_buf[0])
+                set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 }
 
@@ -3819,7 +4090,12 @@ static int g_show(struct seq_file *m, void *v)
                 return 0;
 
         if (ptr == (unsigned long *)1) {
-                seq_printf(m, "#### all functions enabled ####\n");
+                struct ftrace_graph_data *fgd = m->private;
+
+                if (fgd->table == ftrace_graph_funcs)
+                        seq_printf(m, "#### all functions enabled ####\n");
+                else
+                        seq_printf(m, "#### no functions disabled ####\n");
                 return 0;
         }
 
@@ -4447,9 +4723,6 @@ __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
         struct ftrace_ops *op;
         int bit;
 
-        if (function_trace_stop)
-                return;
-
         bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
         if (bit < 0)
                 return;
@@ -4461,9 +4734,8 @@ __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
         preempt_disable_notrace();
         do_for_each_ftrace_op(op, ftrace_ops_list) {
                 if (ftrace_ops_test(op, ip, regs)) {
-                        if (WARN_ON(!op->func)) {
-                                function_trace_stop = 1;
-                                printk("op=%p %pS\n", op, op);
+                        if (FTRACE_WARN_ON(!op->func)) {
+                                pr_warn("op=%p %pS\n", op, op);
                                 goto out;
                         }
                         op->func(ip, parent_ip, op, regs);
@@ -5084,6 +5356,12 @@ int register_ftrace_graph(trace_func_graph_ret_t retfunc,
         /* Function graph doesn't use the .func field of global_ops */
         global_ops.flags |= FTRACE_OPS_FL_STUB;
 
+#ifdef CONFIG_DYNAMIC_FTRACE
+        /* Optimize function graph calling (if implemented by arch) */
+        if (FTRACE_GRAPH_TRAMP_ADDR != 0)
+                global_ops.trampoline = FTRACE_GRAPH_TRAMP_ADDR;
+#endif
+
         ret = ftrace_startup(&global_ops, FTRACE_START_FUNC_RET);
 
 out:
@@ -5104,6 +5382,10 @@ void unregister_ftrace_graph(void)
         __ftrace_graph_entry = ftrace_graph_entry_stub;
         ftrace_shutdown(&global_ops, FTRACE_STOP_FUNC_RET);
         global_ops.flags &= ~FTRACE_OPS_FL_STUB;
+#ifdef CONFIG_DYNAMIC_FTRACE
+        if (FTRACE_GRAPH_TRAMP_ADDR != 0)
+                global_ops.trampoline = 0;
+#endif
         unregister_pm_notifier(&ftrace_suspend_notifier);
         unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
 
@@ -5183,9 +5465,4 @@ void ftrace_graph_exit_task(struct task_struct *t)
 
         kfree(ret_stack);
 }
-
-void ftrace_graph_stop(void)
-{
-        ftrace_stop();
-}
 #endif
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index ff7027199a9a..925f629658d6 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -1689,22 +1689,14 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size,
                         if (!cpu_buffer->nr_pages_to_update)
                                 continue;
 
-                        /* The update must run on the CPU that is being updated. */
-                        preempt_disable();
-                        if (cpu == smp_processor_id() || !cpu_online(cpu)) {
+                        /* Can't run something on an offline CPU. */
+                        if (!cpu_online(cpu)) {
                                 rb_update_pages(cpu_buffer);
                                 cpu_buffer->nr_pages_to_update = 0;
                         } else {
-                                /*
-                                 * Can not disable preemption for schedule_work_on()
-                                 * on PREEMPT_RT.
-                                 */
-                                preempt_enable();
                                 schedule_work_on(cpu,
                                                 &cpu_buffer->update_pages_work);
-                                preempt_disable();
                         }
-                        preempt_enable();
                 }
 
                 /* wait for all the updates to complete */
@@ -1742,22 +1734,14 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size,
 
                 get_online_cpus();
 
-                preempt_disable();
-                /* The update must run on the CPU that is being updated. */
-                if (cpu_id == smp_processor_id() || !cpu_online(cpu_id))
+                /* Can't run something on an offline CPU. */
+                if (!cpu_online(cpu_id))
                         rb_update_pages(cpu_buffer);
                 else {
-                        /*
-                         * Can not disable preemption for schedule_work_on()
-                         * on PREEMPT_RT.
-                         */
-                        preempt_enable();
                         schedule_work_on(cpu_id,
                                          &cpu_buffer->update_pages_work);
                         wait_for_completion(&cpu_buffer->update_done);
-                        preempt_disable();
                 }
-                preempt_enable();
 
                 cpu_buffer->nr_pages_to_update = 0;
                 put_online_cpus();
@@ -3775,7 +3759,7 @@ rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts)
         if (rb_per_cpu_empty(cpu_buffer))
                 return NULL;
 
-        if (iter->head >= local_read(&iter->head_page->page->commit)) {
+        if (iter->head >= rb_page_size(iter->head_page)) {
                 rb_inc_iter(iter);
                 goto again;
         }
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 291397e66669..8bb80fe08767 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -937,30 +937,6 @@ out:
         return ret;
 }
 
-ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt)
-{
-        int len;
-        int ret;
-
-        if (!cnt)
-                return 0;
-
-        if (s->len <= s->readpos)
-                return -EBUSY;
-
-        len = s->len - s->readpos;
-        if (cnt > len)
-                cnt = len;
-        ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);
-        if (ret == cnt)
-                return -EFAULT;
-
-        cnt -= ret;
-
-        s->readpos += cnt;
-        return cnt;
-}
-
 static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
 {
         int len;
@@ -3699,6 +3675,7 @@ static const char readme_msg[] =
 #endif
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
         "  set_graph_function\t- Trace the nested calls of a function (function_graph)\n"
+        "  set_graph_notrace\t- Do not trace the nested calls of a function (function_graph)\n"
         "  max_graph_depth\t- Trace a limited depth of nested calls (0 is unlimited)\n"
 #endif
 #ifdef CONFIG_TRACER_SNAPSHOT
@@ -4238,10 +4215,9 @@ tracing_set_trace_write(struct file *filp, const char __user *ubuf,
 }
 
 static ssize_t
-tracing_max_lat_read(struct file *filp, char __user *ubuf,
-                     size_t cnt, loff_t *ppos)
+tracing_nsecs_read(unsigned long *ptr, char __user *ubuf,
+                   size_t cnt, loff_t *ppos)
 {
-        unsigned long *ptr = filp->private_data;
         char buf[64];
         int r;
 
@@ -4253,10 +4229,9 @@ tracing_max_lat_read(struct file *filp, char __user *ubuf,
 }
 
 static ssize_t
-tracing_max_lat_write(struct file *filp, const char __user *ubuf,
-                      size_t cnt, loff_t *ppos)
+tracing_nsecs_write(unsigned long *ptr, const char __user *ubuf,
+                    size_t cnt, loff_t *ppos)
 {
-        unsigned long *ptr = filp->private_data;
         unsigned long val;
         int ret;
 
@@ -4269,6 +4244,52 @@ tracing_max_lat_write(struct file *filp, const char __user *ubuf,
         return cnt;
 }
 
+static ssize_t
+tracing_thresh_read(struct file *filp, char __user *ubuf,
+                    size_t cnt, loff_t *ppos)
+{
+        return tracing_nsecs_read(&tracing_thresh, ubuf, cnt, ppos);
+}
+
+static ssize_t
+tracing_thresh_write(struct file *filp, const char __user *ubuf,
+                     size_t cnt, loff_t *ppos)
+{
+        struct trace_array *tr = filp->private_data;
+        int ret;
+
+        mutex_lock(&trace_types_lock);
+        ret = tracing_nsecs_write(&tracing_thresh, ubuf, cnt, ppos);
+        if (ret < 0)
+                goto out;
+
+        if (tr->current_trace->update_thresh) {
+                ret = tr->current_trace->update_thresh(tr);
+                if (ret < 0)
+                        goto out;
+        }
+
+        ret = cnt;
+out:
+        mutex_unlock(&trace_types_lock);
+
+        return ret;
+}
+
+static ssize_t
+tracing_max_lat_read(struct file *filp, char __user *ubuf,
+                     size_t cnt, loff_t *ppos)
+{
+        return tracing_nsecs_read(filp->private_data, ubuf, cnt, ppos);
+}
+
+static ssize_t
+tracing_max_lat_write(struct file *filp, const char __user *ubuf,
+                      size_t cnt, loff_t *ppos)
+{
+        return tracing_nsecs_write(filp->private_data, ubuf, cnt, ppos);
+}
+
 static int tracing_open_pipe(struct inode *inode, struct file *filp)
 {
         struct trace_array *tr = inode->i_private;
@@ -5170,6 +5191,13 @@ static int snapshot_raw_open(struct inode *inode, struct file *filp)
 #endif /* CONFIG_TRACER_SNAPSHOT */
 
 
+static const struct file_operations tracing_thresh_fops = {
+        .open           = tracing_open_generic,
+        .read           = tracing_thresh_read,
+        .write          = tracing_thresh_write,
+        .llseek         = generic_file_llseek,
+};
+
 static const struct file_operations tracing_max_lat_fops = {
         .open           = tracing_open_generic,
         .read           = tracing_max_lat_read,
@@ -6107,10 +6135,8 @@ destroy_trace_option_files(struct trace_option_dentry *topts)
         if (!topts)
                 return;
 
-        for (cnt = 0; topts[cnt].opt; cnt++) {
-                if (topts[cnt].entry)
-                        debugfs_remove(topts[cnt].entry);
-        }
+        for (cnt = 0; topts[cnt].opt; cnt++)
+                debugfs_remove(topts[cnt].entry);
 
         kfree(topts);
 }
@@ -6533,7 +6559,7 @@ static __init int tracer_init_debugfs(void)
         init_tracer_debugfs(&global_trace, d_tracer);
 
         trace_create_file("tracing_thresh", 0644, d_tracer,
-                        &tracing_thresh, &tracing_max_lat_fops);
+                        &global_trace, &tracing_thresh_fops);
 
         trace_create_file("README", 0444, d_tracer,
                         NULL, &tracing_readme_fops);
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 9258f5a815db..385391fb1d3b 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -339,6 +339,7 @@ struct tracer_flags {
  * @reset: called when one switches to another tracer
  * @start: called when tracing is unpaused (echo 1 > tracing_enabled)
  * @stop: called when tracing is paused (echo 0 > tracing_enabled)
+ * @update_thresh: called when tracing_thresh is updated
  * @open: called when the trace file is opened
  * @pipe_open: called when the trace_pipe file is opened
  * @close: called when the trace file is released
@@ -357,6 +358,7 @@ struct tracer {
         void                    (*reset)(struct trace_array *tr);
         void                    (*start)(struct trace_array *tr);
         void                    (*stop)(struct trace_array *tr);
+        int                     (*update_thresh)(struct trace_array *tr);
         void                    (*open)(struct trace_iterator *iter);
         void                    (*pipe_open)(struct trace_iterator *iter);
         void                    (*close)(struct trace_iterator *iter);
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 2de53628689f..3154eb39241d 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -8,6 +8,8 @@
  *
  */
 
+#define pr_fmt(fmt) fmt
+
 #include <linux/workqueue.h>
 #include <linux/spinlock.h>
 #include <linux/kthread.h>
@@ -1491,7 +1493,7 @@ event_subsystem_dir(struct trace_array *tr, const char *name,
 
         dir->entry = debugfs_create_dir(name, parent);
         if (!dir->entry) {
-                pr_warning("Failed to create system directory %s\n", name);
+                pr_warn("Failed to create system directory %s\n", name);
                 __put_system(system);
                 goto out_free;
         }
@@ -1507,7 +1509,7 @@ event_subsystem_dir(struct trace_array *tr, const char *name,
         if (!entry) {
                 kfree(system->filter);
                 system->filter = NULL;
-                pr_warning("Could not create debugfs '%s/filter' entry\n", name);
+                pr_warn("Could not create debugfs '%s/filter' entry\n", name);
         }
 
         trace_create_file("enable", 0644, dir->entry, dir,
@@ -1522,8 +1524,7 @@ event_subsystem_dir(struct trace_array *tr, const char *name,
  out_fail:
         /* Only print this message if failed on memory allocation */
         if (!dir || !system)
-                pr_warning("No memory to create event subsystem %s\n",
-                           name);
+                pr_warn("No memory to create event subsystem %s\n", name);
         return NULL;
 }
 
@@ -1551,8 +1552,7 @@ event_create_dir(struct dentry *parent, struct ftrace_event_file *file)
         name = ftrace_event_name(call);
         file->dir = debugfs_create_dir(name, d_events);
         if (!file->dir) {
-                pr_warning("Could not create debugfs '%s' directory\n",
-                           name);
+                pr_warn("Could not create debugfs '%s' directory\n", name);
                 return -1;
         }
 
@@ -1575,8 +1575,8 @@ event_create_dir(struct dentry *parent, struct ftrace_event_file *file)
         if (list_empty(head)) {
                 ret = call->class->define_fields(call);
                 if (ret < 0) {
-                        pr_warning("Could not initialize trace point"
-                                   " events/%s\n", name);
+                        pr_warn("Could not initialize trace point events/%s\n",
+                                name);
                         return -1;
                 }
         }
@@ -1649,8 +1649,7 @@ static int event_init(struct ftrace_event_call *call)
         if (call->class->raw_init) {
                 ret = call->class->raw_init(call);
                 if (ret < 0 && ret != -ENOSYS)
-                        pr_warn("Could not initialize trace events/%s\n",
-                                name);
+                        pr_warn("Could not initialize trace events/%s\n", name);
         }
 
         return ret;
@@ -1895,8 +1894,8 @@ __trace_add_event_dirs(struct trace_array *tr)
         list_for_each_entry(call, &ftrace_events, list) {
                 ret = __trace_add_new_event(call, tr);
                 if (ret < 0)
-                        pr_warning("Could not create directory for event %s\n",
-                                   ftrace_event_name(call));
+                        pr_warn("Could not create directory for event %s\n",
+                                ftrace_event_name(call));
         }
 }
 
@@ -2208,8 +2207,8 @@ __trace_early_add_event_dirs(struct trace_array *tr)
         list_for_each_entry(file, &tr->events, list) {
                 ret = event_create_dir(tr->event_dir, file);
                 if (ret < 0)
-                        pr_warning("Could not create directory for event %s\n",
-                                   ftrace_event_name(file->event_call));
+                        pr_warn("Could not create directory for event %s\n",
+                                ftrace_event_name(file->event_call));
         }
 }
 
@@ -2232,8 +2231,8 @@ __trace_early_add_events(struct trace_array *tr)
 
                 ret = __trace_early_add_new_event(call, tr);
                 if (ret < 0)
-                        pr_warning("Could not create early event %s\n",
-                                   ftrace_event_name(call));
+                        pr_warn("Could not create early event %s\n",
+                                ftrace_event_name(call));
         }
 }
 
@@ -2280,13 +2279,13 @@ create_event_toplevel_files(struct dentry *parent, struct trace_array *tr)
         entry = debugfs_create_file("set_event", 0644, parent,
                                     tr, &ftrace_set_event_fops);
         if (!entry) {
-                pr_warning("Could not create debugfs 'set_event' entry\n");
+                pr_warn("Could not create debugfs 'set_event' entry\n");
                 return -ENOMEM;
         }
 
         d_events = debugfs_create_dir("events", parent);
         if (!d_events) {
-                pr_warning("Could not create debugfs 'events' directory\n");
+                pr_warn("Could not create debugfs 'events' directory\n");
                 return -ENOMEM;
         }
 
@@ -2462,11 +2461,10 @@ static __init int event_trace_init(void)
         entry = debugfs_create_file("available_events", 0444, d_tracer,
                                     tr, &ftrace_avail_fops);
         if (!entry)
-                pr_warning("Could not create debugfs "
-                           "'available_events' entry\n");
+                pr_warn("Could not create debugfs 'available_events' entry\n");
 
         if (trace_define_common_fields())
-                pr_warning("tracing: Failed to allocate common fields");
+                pr_warn("tracing: Failed to allocate common fields");
 
         ret = early_event_add_tracer(d_tracer, tr);
         if (ret)
@@ -2475,7 +2473,7 @@ static __init int event_trace_init(void)
 #ifdef CONFIG_MODULES
         ret = register_module_notifier(&trace_module_nb);
         if (ret)
-                pr_warning("Failed to register trace events module notifier\n");
+                pr_warn("Failed to register trace events module notifier\n");
 #endif
         return 0;
 }
@@ -2579,7 +2577,7 @@ static __init void event_trace_self_tests(void)
                  * it and the self test should not be on.
                  */
                 if (file->flags & FTRACE_EVENT_FL_ENABLED) {
-                        pr_warning("Enabled event during self test!\n");
+                        pr_warn("Enabled event during self test!\n");
                         WARN_ON_ONCE(1);
                         continue;
                 }
@@ -2607,8 +2605,8 @@ static __init void event_trace_self_tests(void)
 
                 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 1);
                 if (WARN_ON_ONCE(ret)) {
-                        pr_warning("error enabling system %s\n",
-                                   system->name);
+                        pr_warn("error enabling system %s\n",
+                                system->name);
                         continue;
                 }
 
@@ -2616,8 +2614,8 @@ static __init void event_trace_self_tests(void)
 
                 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 0);
                 if (WARN_ON_ONCE(ret)) {
-                        pr_warning("error disabling system %s\n",
-                                   system->name);
+                        pr_warn("error disabling system %s\n",
+                                system->name);
                         continue;
                 }
 
@@ -2631,7 +2629,7 @@ static __init void event_trace_self_tests(void)
 
         ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 1);
         if (WARN_ON_ONCE(ret)) {
-                pr_warning("error enabling all events\n");
+                pr_warn("error enabling all events\n");
                 return;
         }
 
@@ -2640,7 +2638,7 @@ static __init void event_trace_self_tests(void)
         /* reset sysname */
         ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 0);
         if (WARN_ON_ONCE(ret)) {
-                pr_warning("error disabling all events\n");
+                pr_warn("error disabling all events\n");
                 return;
         }
 
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 4de3e57f723c..f0a0c982cde3 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -15,6 +15,33 @@
 #include "trace.h"
 #include "trace_output.h"
 
+static bool kill_ftrace_graph;
+
+/**
+ * ftrace_graph_is_dead - returns true if ftrace_graph_stop() was called
+ *
+ * ftrace_graph_stop() is called when a severe error is detected in
+ * the function graph tracing. This function is called by the critical
+ * paths of function graph to keep those paths from doing any more harm.
+ */
+bool ftrace_graph_is_dead(void)
+{
+        return kill_ftrace_graph;
+}
+
+/**
+ * ftrace_graph_stop - set to permanently disable function graph tracincg
+ *
+ * In case of an error int function graph tracing, this is called
+ * to try to keep function graph tracing from causing any more harm.
+ * Usually this is pretty severe and this is called to try to at least
+ * get a warning out to the user.
+ */
+void ftrace_graph_stop(void)
+{
+        kill_ftrace_graph = true;
+}
+
 /* When set, irq functions will be ignored */
 static int ftrace_graph_skip_irqs;
 
@@ -92,6 +119,9 @@ ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
         unsigned long long calltime;
         int index;
 
+        if (unlikely(ftrace_graph_is_dead()))
+                return -EBUSY;
+
         if (!current->ret_stack)
                 return -EBUSY;
 
@@ -323,7 +353,7 @@ int trace_graph_entry(struct ftrace_graph_ent *trace)
         return ret;
 }
 
-int trace_graph_thresh_entry(struct ftrace_graph_ent *trace)
+static int trace_graph_thresh_entry(struct ftrace_graph_ent *trace)
 {
         if (tracing_thresh)
                 return 1;
@@ -412,7 +442,7 @@ void set_graph_array(struct trace_array *tr)
         smp_mb();
 }
 
-void trace_graph_thresh_return(struct ftrace_graph_ret *trace)
+static void trace_graph_thresh_return(struct ftrace_graph_ret *trace)
 {
         if (tracing_thresh &&
             (trace->rettime - trace->calltime < tracing_thresh))
@@ -445,6 +475,12 @@ static void graph_trace_reset(struct trace_array *tr)
         unregister_ftrace_graph();
 }
 
+static int graph_trace_update_thresh(struct trace_array *tr)
+{
+        graph_trace_reset(tr);
+        return graph_trace_init(tr);
+}
+
 static int max_bytes_for_cpu;
 
 static enum print_line_t
@@ -1399,7 +1435,7 @@ static void __print_graph_headers_flags(struct seq_file *s, u32 flags)
         seq_printf(s, "               |   |   |   |\n");
 }
 
-void print_graph_headers(struct seq_file *s)
+static void print_graph_headers(struct seq_file *s)
 {
         print_graph_headers_flags(s, tracer_flags.val);
 }
@@ -1495,6 +1531,7 @@ static struct trace_event graph_trace_ret_event = {
 
 static struct tracer graph_trace __tracer_data = {
         .name           = "function_graph",
+        .update_thresh  = graph_trace_update_thresh,
         .open           = graph_trace_open,
         .pipe_open      = graph_trace_open,
         .close          = graph_trace_close,
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index f3dad80c20b2..c6977d5a9b12 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -20,23 +20,6 @@ static struct hlist_head event_hash[EVENT_HASHSIZE] __read_mostly;
 
 static int next_event_type = __TRACE_LAST_TYPE + 1;
 
-int trace_print_seq(struct seq_file *m, struct trace_seq *s)
-{
-        int len = s->len >= PAGE_SIZE ? PAGE_SIZE - 1 : s->len;
-        int ret;
-
-        ret = seq_write(m, s->buffer, len);
-
-        /*
-         * Only reset this buffer if we successfully wrote to the
-         * seq_file buffer.
-         */
-        if (!ret)
-                trace_seq_init(s);
-
-        return ret;
-}
-
 enum print_line_t trace_print_bputs_msg_only(struct trace_iterator *iter)
 {
         struct trace_seq *s = &iter->seq;
@@ -85,257 +68,6 @@ enum print_line_t trace_print_printk_msg_only(struct trace_iterator *iter)
         return TRACE_TYPE_HANDLED;
 }
 
-/**
- * trace_seq_printf - sequence printing of trace information
- * @s: trace sequence descriptor
- * @fmt: printf format string
- *
- * It returns 0 if the trace oversizes the buffer's free
- * space, 1 otherwise.
- *
- * The tracer may use either sequence operations or its own
- * copy to user routines. To simplify formating of a trace
- * trace_seq_printf is used to store strings into a special
- * buffer (@s). Then the output may be either used by
- * the sequencer or pulled into another buffer.
- */
-int
-trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
-{
-        int len = (PAGE_SIZE - 1) - s->len;
-        va_list ap;
-        int ret;
-
-        if (s->full || !len)
-                return 0;
-
-        va_start(ap, fmt);
-        ret = vsnprintf(s->buffer + s->len, len, fmt, ap);
-        va_end(ap);
-
-        /* If we can't write it all, don't bother writing anything */
-        if (ret >= len) {
-                s->full = 1;
-                return 0;
-        }
-
-        s->len += ret;
-
-        return 1;
-}
-EXPORT_SYMBOL_GPL(trace_seq_printf);
-
-/**
- * trace_seq_bitmask - put a list of longs as a bitmask print output
- * @s:          trace sequence descriptor
- * @maskp:      points to an array of unsigned longs that represent a bitmask
- * @nmaskbits:  The number of bits that are valid in @maskp
- *
- * It returns 0 if the trace oversizes the buffer's free
- * space, 1 otherwise.
- *
- * Writes a ASCII representation of a bitmask string into @s.
- */
-int
-trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
-                  int nmaskbits)
-{
-        int len = (PAGE_SIZE - 1) - s->len;
-        int ret;
-
-        if (s->full || !len)
-                return 0;
-
-        ret = bitmap_scnprintf(s->buffer, len, maskp, nmaskbits);
-        s->len += ret;
-
-        return 1;
-}
-EXPORT_SYMBOL_GPL(trace_seq_bitmask);
-
-/**
- * trace_seq_vprintf - sequence printing of trace information
- * @s: trace sequence descriptor
- * @fmt: printf format string
- *
- * The tracer may use either sequence operations or its own
- * copy to user routines. To simplify formating of a trace
- * trace_seq_printf is used to store strings into a special
- * buffer (@s). Then the output may be either used by
- * the sequencer or pulled into another buffer.
- */
-int
-trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)
-{
-        int len = (PAGE_SIZE - 1) - s->len;
-        int ret;
-
-        if (s->full || !len)
-                return 0;
-
-        ret = vsnprintf(s->buffer + s->len, len, fmt, args);
-
-        /* If we can't write it all, don't bother writing anything */
-        if (ret >= len) {
-                s->full = 1;
-                return 0;
-        }
-
-        s->len += ret;
-
-        return len;
-}
-EXPORT_SYMBOL_GPL(trace_seq_vprintf);
-
-int trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
-{
-        int len = (PAGE_SIZE - 1) - s->len;
-        int ret;
-
-        if (s->full || !len)
-                return 0;
-
-        ret = bstr_printf(s->buffer + s->len, len, fmt, binary);
-
-        /* If we can't write it all, don't bother writing anything */
-        if (ret >= len) {
-                s->full = 1;
-                return 0;
-        }
-
-        s->len += ret;
-
-        return len;
-}
-
-/**
- * trace_seq_puts - trace sequence printing of simple string
- * @s: trace sequence descriptor
- * @str: simple string to record
- *
- * The tracer may use either the sequence operations or its own
- * copy to user routines. This function records a simple string
- * into a special buffer (@s) for later retrieval by a sequencer
- * or other mechanism.
- */
-int trace_seq_puts(struct trace_seq *s, const char *str)
-{
-        int len = strlen(str);
-
-        if (s->full)
-                return 0;
-
-        if (len > ((PAGE_SIZE - 1) - s->len)) {
-                s->full = 1;
-                return 0;
-        }
-
-        memcpy(s->buffer + s->len, str, len);
-        s->len += len;
-
-        return len;
-}
-
-int trace_seq_putc(struct trace_seq *s, unsigned char c)
-{
-        if (s->full)
-                return 0;
-
-        if (s->len >= (PAGE_SIZE - 1)) {
-                s->full = 1;
-                return 0;
-        }
-
-        s->buffer[s->len++] = c;
-
-        return 1;
-}
-EXPORT_SYMBOL(trace_seq_putc);
-
-int trace_seq_putmem(struct trace_seq *s, const void *mem, size_t len)
-{
-        if (s->full)
-                return 0;
-
-        if (len > ((PAGE_SIZE - 1) - s->len)) {
-                s->full = 1;
-                return 0;
-        }
-
-        memcpy(s->buffer + s->len, mem, len);
-        s->len += len;
-
-        return len;
-}
-
-int trace_seq_putmem_hex(struct trace_seq *s, const void *mem, size_t len)
-{
-        unsigned char hex[HEX_CHARS];
-        const unsigned char *data = mem;
-        int i, j;
-
-        if (s->full)
-                return 0;
-
-#ifdef __BIG_ENDIAN
-        for (i = 0, j = 0; i < len; i++) {
-#else
-        for (i = len-1, j = 0; i >= 0; i--) {
-#endif
-                hex[j++] = hex_asc_hi(data[i]);
-                hex[j++] = hex_asc_lo(data[i]);
-        }
-        hex[j++] = ' ';
-
-        return trace_seq_putmem(s, hex, j);
-}
-
-void *trace_seq_reserve(struct trace_seq *s, size_t len)
-{
-        void *ret;
-
-        if (s->full)
-                return NULL;
-
-        if (len > ((PAGE_SIZE - 1) - s->len)) {
-                s->full = 1;
-                return NULL;
-        }
-
-        ret = s->buffer + s->len;
-        s->len += len;
-
-        return ret;
-}
-
-int trace_seq_path(struct trace_seq *s, const struct path *path)
-{
-        unsigned char *p;
-
-        if (s->full)
-                return 0;
-
-        if (s->len >= (PAGE_SIZE - 1)) {
-                s->full = 1;
-                return 0;
-        }
-
-        p = d_path(path, s->buffer + s->len, PAGE_SIZE - s->len);
-        if (!IS_ERR(p)) {
-                p = mangle_path(s->buffer + s->len, p, "\n");
-                if (p) {
-                        s->len = p - s->buffer;
-                        return 1;
-                }
-        } else {
-                s->buffer[s->len++] = '?';
-                return 1;
-        }
-
-        s->full = 1;
-        return 0;
-}
-
 const char *
 ftrace_print_flags_seq(struct trace_seq *p, const char *delim,
                        unsigned long flags,
@@ -343,7 +75,7 @@ ftrace_print_flags_seq(struct trace_seq *p, const char *delim,
 {
         unsigned long mask;
         const char *str;
-        const char *ret = p->buffer + p->len;
+        const char *ret = trace_seq_buffer_ptr(p);
         int i, first = 1;
 
         for (i = 0;  flag_array[i].name && flags; i++) {
@@ -379,7 +111,7 @@ ftrace_print_symbols_seq(struct trace_seq *p, unsigned long val,
                          const struct trace_print_flags *symbol_array)
 {
         int i;
-        const char *ret = p->buffer + p->len;
+        const char *ret = trace_seq_buffer_ptr(p);
 
         for (i = 0;  symbol_array[i].name; i++) {
 
@@ -390,7 +122,7 @@ ftrace_print_symbols_seq(struct trace_seq *p, unsigned long val,
                 break;
         }
 
-        if (ret == (const char *)(p->buffer + p->len))
+        if (ret == (const char *)(trace_seq_buffer_ptr(p)))
                 trace_seq_printf(p, "0x%lx", val);
                 
         trace_seq_putc(p, 0);
@@ -405,7 +137,7 @@ ftrace_print_symbols_seq_u64(struct trace_seq *p, unsigned long long val,
                          const struct trace_print_flags_u64 *symbol_array)
 {
         int i;
-        const char *ret = p->buffer + p->len;
+        const char *ret = trace_seq_buffer_ptr(p);
 
         for (i = 0;  symbol_array[i].name; i++) {
 
@@ -416,7 +148,7 @@ ftrace_print_symbols_seq_u64(struct trace_seq *p, unsigned long long val,
                 break;
         }
 
-        if (ret == (const char *)(p->buffer + p->len))
+        if (ret == (const char *)(trace_seq_buffer_ptr(p)))
                 trace_seq_printf(p, "0x%llx", val);
 
         trace_seq_putc(p, 0);
@@ -430,7 +162,7 @@ const char *
 ftrace_print_bitmask_seq(struct trace_seq *p, void *bitmask_ptr,
                          unsigned int bitmask_size)
 {
-        const char *ret = p->buffer + p->len;
+        const char *ret = trace_seq_buffer_ptr(p);
 
         trace_seq_bitmask(p, bitmask_ptr, bitmask_size * 8);
         trace_seq_putc(p, 0);
@@ -443,7 +175,7 @@ const char *
 ftrace_print_hex_seq(struct trace_seq *p, const unsigned char *buf, int buf_len)
 {
         int i;
-        const char *ret = p->buffer + p->len;
+        const char *ret = trace_seq_buffer_ptr(p);
 
         for (i = 0; i < buf_len; i++)
                 trace_seq_printf(p, "%s%2.2x", i == 0 ? "" : " ", buf[i]);
diff --git a/kernel/trace/trace_output.h b/kernel/trace/trace_output.h
index 127a9d8c8357..80b25b585a70 100644
--- a/kernel/trace/trace_output.h
+++ b/kernel/trace/trace_output.h
@@ -35,9 +35,6 @@ trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry);
 extern int __unregister_ftrace_event(struct trace_event *event);
 extern struct rw_semaphore trace_event_sem;
 
-#define MAX_MEMHEX_BYTES        8
-#define HEX_CHARS               (MAX_MEMHEX_BYTES*2 + 1)
-
 #define SEQ_PUT_FIELD_RET(s, x)                         \
 do {                                                    \
         if (!trace_seq_putmem(s, &(x), sizeof(x)))      \
@@ -46,7 +43,6 @@ do {							\
 
 #define SEQ_PUT_HEX_FIELD_RET(s, x)                     \
 do {                                                    \
-        BUILD_BUG_ON(sizeof(x) > MAX_MEMHEX_BYTES);     \
         if (!trace_seq_putmem_hex(s, &(x), sizeof(x)))  \
                 return TRACE_TYPE_PARTIAL_LINE;         \
 } while (0)
diff --git a/kernel/trace/trace_seq.c b/kernel/trace/trace_seq.c
new file mode 100644
index 000000000000..1f24ed99dca2
--- /dev/null
+++ b/kernel/trace/trace_seq.c
@@ -0,0 +1,428 @@
+/*
+ * trace_seq.c
+ *
+ * Copyright (C) 2008-2014 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
+ *
+ * The trace_seq is a handy tool that allows you to pass a descriptor around
+ * to a buffer that other functions can write to. It is similar to the
+ * seq_file functionality but has some differences.
+ *
+ * To use it, the trace_seq must be initialized with trace_seq_init().
+ * This will set up the counters within the descriptor. You can call
+ * trace_seq_init() more than once to reset the trace_seq to start
+ * from scratch.
+ * 
+ * The buffer size is currently PAGE_SIZE, although it may become dynamic
+ * in the future.
+ *
+ * A write to the buffer will either succed or fail. That is, unlike
+ * sprintf() there will not be a partial write (well it may write into
+ * the buffer but it wont update the pointers). This allows users to
+ * try to write something into the trace_seq buffer and if it fails
+ * they can flush it and try again.
+ *
+ */
+#include <linux/uaccess.h>
+#include <linux/seq_file.h>
+#include <linux/trace_seq.h>
+
+/* How much buffer is left on the trace_seq? */
+#define TRACE_SEQ_BUF_LEFT(s) ((PAGE_SIZE - 1) - (s)->len)
+
+/* How much buffer is written? */
+#define TRACE_SEQ_BUF_USED(s) min((s)->len, (unsigned int)(PAGE_SIZE - 1))
+
+/**
+ * trace_print_seq - move the contents of trace_seq into a seq_file
+ * @m: the seq_file descriptor that is the destination
+ * @s: the trace_seq descriptor that is the source.
+ *
+ * Returns 0 on success and non zero on error. If it succeeds to
+ * write to the seq_file it will reset the trace_seq, otherwise
+ * it does not modify the trace_seq to let the caller try again.
+ */
+int trace_print_seq(struct seq_file *m, struct trace_seq *s)
+{
+        unsigned int len = TRACE_SEQ_BUF_USED(s);
+        int ret;
+
+        ret = seq_write(m, s->buffer, len);
+
+        /*
+         * Only reset this buffer if we successfully wrote to the
+         * seq_file buffer. This lets the caller try again or
+         * do something else with the contents.
+         */
+        if (!ret)
+                trace_seq_init(s);
+
+        return ret;
+}
+
+/**
+ * trace_seq_printf - sequence printing of trace information
+ * @s: trace sequence descriptor
+ * @fmt: printf format string
+ *
+ * The tracer may use either sequence operations or its own
+ * copy to user routines. To simplify formating of a trace
+ * trace_seq_printf() is used to store strings into a special
+ * buffer (@s). Then the output may be either used by
+ * the sequencer or pulled into another buffer.
+ *
+ * Returns 1 if we successfully written all the contents to
+ *   the buffer.
+  * Returns 0 if we the length to write is bigger than the
+ *   reserved buffer space. In this case, nothing gets written.
+ */
+int trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
+{
+        unsigned int len = TRACE_SEQ_BUF_LEFT(s);
+        va_list ap;
+        int ret;
+
+        if (s->full || !len)
+                return 0;
+
+        va_start(ap, fmt);
+        ret = vsnprintf(s->buffer + s->len, len, fmt, ap);
+        va_end(ap);
+
+        /* If we can't write it all, don't bother writing anything */
+        if (ret >= len) {
+                s->full = 1;
+                return 0;
+        }
+
+        s->len += ret;
+
+        return 1;
+}
+EXPORT_SYMBOL_GPL(trace_seq_printf);
+
+/**
+ * trace_seq_bitmask - write a bitmask array in its ASCII representation
+ * @s:          trace sequence descriptor
+ * @maskp:      points to an array of unsigned longs that represent a bitmask
+ * @nmaskbits:  The number of bits that are valid in @maskp
+ *
+ * Writes a ASCII representation of a bitmask string into @s.
+ *
+ * Returns 1 if we successfully written all the contents to
+ *   the buffer.
+ * Returns 0 if we the length to write is bigger than the
+ *   reserved buffer space. In this case, nothing gets written.
+ */
+int trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
+                      int nmaskbits)
+{
+        unsigned int len = TRACE_SEQ_BUF_LEFT(s);
+        int ret;
+
+        if (s->full || !len)
+                return 0;
+
+        ret = bitmap_scnprintf(s->buffer, len, maskp, nmaskbits);
+        s->len += ret;
+
+        return 1;
+}
+EXPORT_SYMBOL_GPL(trace_seq_bitmask);
+
+/**
+ * trace_seq_vprintf - sequence printing of trace information
+ * @s: trace sequence descriptor
+ * @fmt: printf format string
+ *
+ * The tracer may use either sequence operations or its own
+ * copy to user routines. To simplify formating of a trace
+ * trace_seq_printf is used to store strings into a special
+ * buffer (@s). Then the output may be either used by
+ * the sequencer or pulled into another buffer.
+ *
+ * Returns how much it wrote to the buffer.
+ */
+int trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)
+{
+        unsigned int len = TRACE_SEQ_BUF_LEFT(s);
+        int ret;
+
+        if (s->full || !len)
+                return 0;
+
+        ret = vsnprintf(s->buffer + s->len, len, fmt, args);
+
+        /* If we can't write it all, don't bother writing anything */
+        if (ret >= len) {
+                s->full = 1;
+                return 0;
+        }
+
+        s->len += ret;
+
+        return len;
+}
+EXPORT_SYMBOL_GPL(trace_seq_vprintf);
+
+/**
+ * trace_seq_bprintf - Write the printf string from binary arguments
+ * @s: trace sequence descriptor
+ * @fmt: The format string for the @binary arguments
+ * @binary: The binary arguments for @fmt.
+ *
+ * When recording in a fast path, a printf may be recorded with just
+ * saving the format and the arguments as they were passed to the
+ * function, instead of wasting cycles converting the arguments into
+ * ASCII characters. Instead, the arguments are saved in a 32 bit
+ * word array that is defined by the format string constraints.
+ *
+ * This function will take the format and the binary array and finish
+ * the conversion into the ASCII string within the buffer.
+ *
+ * Returns how much it wrote to the buffer.
+ */
+int trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
+{
+        unsigned int len = TRACE_SEQ_BUF_LEFT(s);
+        int ret;
+
+        if (s->full || !len)
+                return 0;
+
+        ret = bstr_printf(s->buffer + s->len, len, fmt, binary);
+
+        /* If we can't write it all, don't bother writing anything */
+        if (ret >= len) {
+                s->full = 1;
+                return 0;
+        }
+
+        s->len += ret;
+
+        return len;
+}
+EXPORT_SYMBOL_GPL(trace_seq_bprintf);
+
+/**
+ * trace_seq_puts - trace sequence printing of simple string
+ * @s: trace sequence descriptor
+ * @str: simple string to record
+ *
+ * The tracer may use either the sequence operations or its own
+ * copy to user routines. This function records a simple string
+ * into a special buffer (@s) for later retrieval by a sequencer
+ * or other mechanism.
+ *
+ * Returns how much it wrote to the buffer.
+ */
+int trace_seq_puts(struct trace_seq *s, const char *str)
+{
+        unsigned int len = strlen(str);
+
+        if (s->full)
+                return 0;
+
+        if (len > TRACE_SEQ_BUF_LEFT(s)) {
+                s->full = 1;
+                return 0;
+        }
+
+        memcpy(s->buffer + s->len, str, len);
+        s->len += len;
+
+        return len;
+}
+EXPORT_SYMBOL_GPL(trace_seq_puts);
+
+/**
+ * trace_seq_putc - trace sequence printing of simple character
+ * @s: trace sequence descriptor
+ * @c: simple character to record
+ *
+ * The tracer may use either the sequence operations or its own
+ * copy to user routines. This function records a simple charater
+ * into a special buffer (@s) for later retrieval by a sequencer
+ * or other mechanism.
+ *
+ * Returns how much it wrote to the buffer.
+ */
+int trace_seq_putc(struct trace_seq *s, unsigned char c)
+{
+        if (s->full)
+                return 0;
+
+        if (TRACE_SEQ_BUF_LEFT(s) < 1) {
+                s->full = 1;
+                return 0;
+        }
+
+        s->buffer[s->len++] = c;
+
+        return 1;
+}
+EXPORT_SYMBOL_GPL(trace_seq_putc);
+
+/**
+ * trace_seq_putmem - write raw data into the trace_seq buffer
+ * @s: trace sequence descriptor
+ * @mem: The raw memory to copy into the buffer
+ * @len: The length of the raw memory to copy (in bytes)
+ *
+ * There may be cases where raw memory needs to be written into the
+ * buffer and a strcpy() would not work. Using this function allows
+ * for such cases.
+ *
+ * Returns how much it wrote to the buffer.
+ */
+int trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len)
+{
+        if (s->full)
+                return 0;
+
+        if (len > TRACE_SEQ_BUF_LEFT(s)) {
+                s->full = 1;
+                return 0;
+        }
+
+        memcpy(s->buffer + s->len, mem, len);
+        s->len += len;
+
+        return len;
+}
+EXPORT_SYMBOL_GPL(trace_seq_putmem);
+
+#define MAX_MEMHEX_BYTES        8U
+#define HEX_CHARS               (MAX_MEMHEX_BYTES*2 + 1)
+
+/**
+ * trace_seq_putmem_hex - write raw memory into the buffer in ASCII hex
+ * @s: trace sequence descriptor
+ * @mem: The raw memory to write its hex ASCII representation of
+ * @len: The length of the raw memory to copy (in bytes)
+ *
+ * This is similar to trace_seq_putmem() except instead of just copying the
+ * raw memory into the buffer it writes its ASCII representation of it
+ * in hex characters.
+ *
+ * Returns how much it wrote to the buffer.
+ */
+int trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
+                         unsigned int len)
+{
+        unsigned char hex[HEX_CHARS];
+        const unsigned char *data = mem;
+        unsigned int start_len;
+        int i, j;
+        int cnt = 0;
+
+        if (s->full)
+                return 0;
+
+        while (len) {
+                start_len = min(len, HEX_CHARS - 1);
+#ifdef __BIG_ENDIAN
+                for (i = 0, j = 0; i < start_len; i++) {
+#else
+                for (i = start_len-1, j = 0; i >= 0; i--) {
+#endif
+                        hex[j++] = hex_asc_hi(data[i]);
+                        hex[j++] = hex_asc_lo(data[i]);
+                }
+                if (WARN_ON_ONCE(j == 0 || j/2 > len))
+                        break;
+
+                /* j increments twice per loop */
+                len -= j / 2;
+                hex[j++] = ' ';
+
+                cnt += trace_seq_putmem(s, hex, j);
+        }
+        return cnt;
+}
+EXPORT_SYMBOL_GPL(trace_seq_putmem_hex);
+
+/**
+ * trace_seq_path - copy a path into the sequence buffer
+ * @s: trace sequence descriptor
+ * @path: path to write into the sequence buffer.
+ *
+ * Write a path name into the sequence buffer.
+ *
+ * Returns 1 if we successfully written all the contents to
+ *   the buffer.
+ * Returns 0 if we the length to write is bigger than the
+ *   reserved buffer space. In this case, nothing gets written.
+ */
+int trace_seq_path(struct trace_seq *s, const struct path *path)
+{
+        unsigned char *p;
+
+        if (s->full)
+                return 0;
+
+        if (TRACE_SEQ_BUF_LEFT(s) < 1) {
+                s->full = 1;
+                return 0;
+        }
+
+        p = d_path(path, s->buffer + s->len, PAGE_SIZE - s->len);
+        if (!IS_ERR(p)) {
+                p = mangle_path(s->buffer + s->len, p, "\n");
+                if (p) {
+                        s->len = p - s->buffer;
+                        return 1;
+                }
+        } else {
+                s->buffer[s->len++] = '?';
+                return 1;
+        }
+
+        s->full = 1;
+        return 0;
+}
+EXPORT_SYMBOL_GPL(trace_seq_path);
+
+/**
+ * trace_seq_to_user - copy the squence buffer to user space
+ * @s: trace sequence descriptor
+ * @ubuf: The userspace memory location to copy to
+ * @cnt: The amount to copy
+ *
+ * Copies the sequence buffer into the userspace memory pointed to
+ * by @ubuf. It starts from the last read position (@s->readpos)
+ * and writes up to @cnt characters or till it reaches the end of
+ * the content in the buffer (@s->len), which ever comes first.
+ *
+ * On success, it returns a positive number of the number of bytes
+ * it copied.
+ *
+ * On failure it returns -EBUSY if all of the content in the
+ * sequence has been already read, which includes nothing in the
+ * sequenc (@s->len == @s->readpos).
+ *
+ * Returns -EFAULT if the copy to userspace fails.
+ */
+int trace_seq_to_user(struct trace_seq *s, char __user *ubuf, int cnt)
+{
+        int len;
+        int ret;
+
+        if (!cnt)
+                return 0;
+
+        if (s->len <= s->readpos)
+                return -EBUSY;
+
+        len = s->len - s->readpos;
+        if (cnt > len)
+                cnt = len;
+        ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);
+        if (ret == cnt)
+                return -EFAULT;
+
+        cnt -= ret;
+
+        s->readpos += cnt;
+        return cnt;
+}
+EXPORT_SYMBOL_GPL(trace_seq_to_user);