Merge ../linux-2.6

18 files changed, 530 insertions, 195 deletions

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 882c51048993..e1d4764435ed 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -505,6 +505,18 @@ config DEBUG_WRITECOUNT
 
           If unsure, say N.
 
+config DEBUG_MEMORY_INIT
+        bool "Debug memory initialisation" if EMBEDDED
+        default !EMBEDDED
+        help
+          Enable this for additional checks during memory initialisation.
+          The sanity checks verify aspects of the VM such as the memory model
+          and other information provided by the architecture. Verbose
+          information will be printed at KERN_DEBUG loglevel depending
+          on the mminit_loglevel= command-line option.
+
+          If unsure, say Y
+
 config DEBUG_LIST
         bool "Debug linked list manipulation"
         depends on DEBUG_KERNEL
diff --git a/lib/Makefile b/lib/Makefile
index 818c4d455518..3b1f94bbe9de 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -11,14 +11,14 @@ lib-y := ctype.o string.o vsprintf.o cmdline.o \
          rbtree.o radix-tree.o dump_stack.o \
          idr.o int_sqrt.o extable.o prio_tree.o \
          sha1.o irq_regs.o reciprocal_div.o argv_split.o \
-         proportions.o prio_heap.o ratelimit.o
+         proportions.o prio_heap.o ratelimit.o show_mem.o
 
 lib-$(CONFIG_MMU) += ioremap.o
 lib-$(CONFIG_SMP) += cpumask.o
 
 lib-y   += kobject.o kref.o klist.o
 
-obj-y += div64.o sort.o parser.o halfmd4.o debug_locks.o random32.o \
+obj-y += bcd.o div64.o sort.o parser.o halfmd4.o debug_locks.o random32.o \
          bust_spinlocks.o hexdump.o kasprintf.o bitmap.o scatterlist.o
 
 ifeq ($(CONFIG_DEBUG_KOBJECT),y)
@@ -78,6 +78,8 @@ lib-$(CONFIG_GENERIC_BUG) += bug.o
 
 obj-$(CONFIG_HAVE_LMB) += lmb.o
 
+obj-$(CONFIG_HAVE_ARCH_TRACEHOOK) += syscall.o
+
 hostprogs-y     := gen_crc32table
 clean-files     := crc32table.h
 
diff --git a/lib/bcd.c b/lib/bcd.c
new file mode 100644
index 000000000000..d74257fd0fe7
--- /dev/null
+++ b/lib/bcd.c
@@ -0,0 +1,14 @@
+#include <linux/bcd.h>
+#include <linux/module.h>
+
+unsigned bcd2bin(unsigned char val)
+{
+        return (val & 0x0f) + (val >> 4) * 10;
+}
+EXPORT_SYMBOL(bcd2bin);
+
+unsigned char bin2bcd(unsigned val)
+{
+        return ((val / 10) << 4) + val % 10;
+}
+EXPORT_SYMBOL(bin2bcd);
diff --git a/lib/cmdline.c b/lib/cmdline.c
index f596c08d213a..5ba8a942a478 100644
--- a/lib/cmdline.c
+++ b/lib/cmdline.c
@@ -116,7 +116,7 @@ char *get_options(const char *str, int nints, int *ints)
 /**
  *      memparse - parse a string with mem suffixes into a number
  *      @ptr: Where parse begins
- *      @retptr: (output) Pointer to next char after parse completes
+ *      @retptr: (output) Optional pointer to next char after parse completes
  *
  *      Parses a string into a number.  The number stored at @ptr is
  *      potentially suffixed with %K (for kilobytes, or 1024 bytes),
@@ -126,11 +126,13 @@ char *get_options(const char *str, int nints, int *ints)
  *      megabyte, or one gigabyte, respectively.
  */
 
-unsigned long long memparse (char *ptr, char **retptr)
+unsigned long long memparse(char *ptr, char **retptr)
 {
-        unsigned long long ret = simple_strtoull (ptr, retptr, 0);
+        char *endptr;   /* local pointer to end of parsed string */
 
-        switch (**retptr) {
+        unsigned long long ret = simple_strtoull(ptr, &endptr, 0);
+
+        switch (*endptr) {
         case 'G':
         case 'g':
                 ret <<= 10;
@@ -140,10 +142,14 @@ unsigned long long memparse (char *ptr, char **retptr)
         case 'K':
         case 'k':
                 ret <<= 10;
-                (*retptr)++;
+                endptr++;
         default:
                 break;
         }
+
+        if (retptr)
+                *retptr = endptr;
+
         return ret;
 }
 
diff --git a/lib/debugobjects.c b/lib/debugobjects.c
index 85b18d79be89..45a6bde762d1 100644
--- a/lib/debugobjects.c
+++ b/lib/debugobjects.c
@@ -205,9 +205,8 @@ static void debug_print_object(struct debug_obj *obj, char *msg)
 
         if (limit < 5 && obj->descr != descr_test) {
                 limit++;
-                printk(KERN_ERR "ODEBUG: %s %s object type: %s\n", msg,
+                WARN(1, KERN_ERR "ODEBUG: %s %s object type: %s\n", msg,
                        obj_states[obj->state], obj->descr->name);
-                WARN_ON(1);
         }
         debug_objects_warnings++;
 }
@@ -226,15 +225,13 @@ debug_object_fixup(int (*fixup)(void *addr, enum debug_obj_state state),
 
 static void debug_object_is_on_stack(void *addr, int onstack)
 {
-        void *stack = current->stack;
         int is_on_stack;
         static int limit;
 
         if (limit > 4)
                 return;
 
-        is_on_stack = (addr >= stack && addr < (stack + THREAD_SIZE));
-
+        is_on_stack = object_is_on_stack(addr);
         if (is_on_stack == onstack)
                 return;
 
@@ -735,26 +732,22 @@ check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
 
         obj = lookup_object(addr, db);
         if (!obj && state != ODEBUG_STATE_NONE) {
-                printk(KERN_ERR "ODEBUG: selftest object not found\n");
-                WARN_ON(1);
+                WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
                 goto out;
         }
         if (obj && obj->state != state) {
-                printk(KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
+                WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
                        obj->state, state);
-                WARN_ON(1);
                 goto out;
         }
         if (fixups != debug_objects_fixups) {
-                printk(KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
+                WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
                        fixups, debug_objects_fixups);
-                WARN_ON(1);
                 goto out;
         }
         if (warnings != debug_objects_warnings) {
-                printk(KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
+                WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
                        warnings, debug_objects_warnings);
-                WARN_ON(1);
                 goto out;
         }
         res = 0;
diff --git a/lib/idr.c b/lib/idr.c
index 7a02e173f027..e728c7fccc4d 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -6,6 +6,8 @@
  * Modified by George Anzinger to reuse immediately and to use
  * find bit instructions.  Also removed _irq on spinlocks.
  *
+ * Modified by Nadia Derbey to make it RCU safe.
+ *
  * Small id to pointer translation service.
  *
  * It uses a radix tree like structure as a sparse array indexed
@@ -35,7 +37,7 @@
 
 static struct kmem_cache *idr_layer_cache;
 
-static struct idr_layer *alloc_layer(struct idr *idp)
+static struct idr_layer *get_from_free_list(struct idr *idp)
 {
         struct idr_layer *p;
         unsigned long flags;
@@ -50,15 +52,28 @@ static struct idr_layer *alloc_layer(struct idr *idp)
         return(p);
 }
 
+static void idr_layer_rcu_free(struct rcu_head *head)
+{
+        struct idr_layer *layer;
+
+        layer = container_of(head, struct idr_layer, rcu_head);
+        kmem_cache_free(idr_layer_cache, layer);
+}
+
+static inline void free_layer(struct idr_layer *p)
+{
+        call_rcu(&p->rcu_head, idr_layer_rcu_free);
+}
+
 /* only called when idp->lock is held */
-static void __free_layer(struct idr *idp, struct idr_layer *p)
+static void __move_to_free_list(struct idr *idp, struct idr_layer *p)
 {
         p->ary[0] = idp->id_free;
         idp->id_free = p;
         idp->id_free_cnt++;
 }
 
-static void free_layer(struct idr *idp, struct idr_layer *p)
+static void move_to_free_list(struct idr *idp, struct idr_layer *p)
 {
         unsigned long flags;
 
@@ -66,7 +81,7 @@ static void free_layer(struct idr *idp, struct idr_layer *p)
          * Depends on the return element being zeroed.
          */
         spin_lock_irqsave(&idp->lock, flags);
-        __free_layer(idp, p);
+        __move_to_free_list(idp, p);
         spin_unlock_irqrestore(&idp->lock, flags);
 }
 
@@ -96,7 +111,7 @@ static void idr_mark_full(struct idr_layer **pa, int id)
  * @gfp_mask:   memory allocation flags
  *
  * This function should be called prior to locking and calling the
- * following function.  It preallocates enough memory to satisfy
+ * idr_get_new* functions. It preallocates enough memory to satisfy
  * the worst possible allocation.
  *
  * If the system is REALLY out of memory this function returns 0,
@@ -109,7 +124,7 @@ int idr_pre_get(struct idr *idp, gfp_t gfp_mask)
                 new = kmem_cache_alloc(idr_layer_cache, gfp_mask);
                 if (new == NULL)
                         return (0);
-                free_layer(idp, new);
+                move_to_free_list(idp, new);
         }
         return 1;
 }
@@ -143,7 +158,7 @@ static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa)
                         /* if already at the top layer, we need to grow */
                         if (!(p = pa[l])) {
                                 *starting_id = id;
-                                return -2;
+                                return IDR_NEED_TO_GROW;
                         }
 
                         /* If we need to go up one layer, continue the
@@ -160,16 +175,17 @@ static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa)
                         id = ((id >> sh) ^ n ^ m) << sh;
                 }
                 if ((id >= MAX_ID_BIT) || (id < 0))
-                        return -3;
+                        return IDR_NOMORE_SPACE;
                 if (l == 0)
                         break;
                 /*
                  * Create the layer below if it is missing.
                  */
                 if (!p->ary[m]) {
-                        if (!(new = alloc_layer(idp)))
+                        new = get_from_free_list(idp);
+                        if (!new)
                                 return -1;
-                        p->ary[m] = new;
+                        rcu_assign_pointer(p->ary[m], new);
                         p->count++;
                 }
                 pa[l--] = p;
@@ -192,7 +208,7 @@ build_up:
         p = idp->top;
         layers = idp->layers;
         if (unlikely(!p)) {
-                if (!(p = alloc_layer(idp)))
+                if (!(p = get_from_free_list(idp)))
                         return -1;
                 layers = 1;
         }
@@ -204,7 +220,7 @@ build_up:
                 layers++;
                 if (!p->count)
                         continue;
-                if (!(new = alloc_layer(idp))) {
+                if (!(new = get_from_free_list(idp))) {
                         /*
                          * The allocation failed.  If we built part of
                          * the structure tear it down.
@@ -214,7 +230,7 @@ build_up:
                                 p = p->ary[0];
                                 new->ary[0] = NULL;
                                 new->bitmap = new->count = 0;
-                                __free_layer(idp, new);
+                                __move_to_free_list(idp, new);
                         }
                         spin_unlock_irqrestore(&idp->lock, flags);
                         return -1;
@@ -225,10 +241,10 @@ build_up:
                         __set_bit(0, &new->bitmap);
                 p = new;
         }
-        idp->top = p;
+        rcu_assign_pointer(idp->top, p);
         idp->layers = layers;
         v = sub_alloc(idp, &id, pa);
-        if (v == -2)
+        if (v == IDR_NEED_TO_GROW)
                 goto build_up;
         return(v);
 }
@@ -244,7 +260,8 @@ static int idr_get_new_above_int(struct idr *idp, void *ptr, int starting_id)
                  * Successfully found an empty slot.  Install the user
                  * pointer and mark the slot full.
                  */
-                pa[0]->ary[id & IDR_MASK] = (struct idr_layer *)ptr;
+                rcu_assign_pointer(pa[0]->ary[id & IDR_MASK],
+                                (struct idr_layer *)ptr);
                 pa[0]->count++;
                 idr_mark_full(pa, id);
         }
@@ -277,12 +294,8 @@ int idr_get_new_above(struct idr *idp, void *ptr, int starting_id, int *id)
          * This is a cheap hack until the IDR code can be fixed to
          * return proper error values.
          */
-        if (rv < 0) {
-                if (rv == -1)
-                        return -EAGAIN;
-                else /* Will be -3 */
-                        return -ENOSPC;
-        }
+        if (rv < 0)
+                return _idr_rc_to_errno(rv);
         *id = rv;
         return 0;
 }
@@ -312,12 +325,8 @@ int idr_get_new(struct idr *idp, void *ptr, int *id)
          * This is a cheap hack until the IDR code can be fixed to
          * return proper error values.
          */
-        if (rv < 0) {
-                if (rv == -1)
-                        return -EAGAIN;
-                else /* Will be -3 */
-                        return -ENOSPC;
-        }
+        if (rv < 0)
+                return _idr_rc_to_errno(rv);
         *id = rv;
         return 0;
 }
@@ -325,7 +334,8 @@ EXPORT_SYMBOL(idr_get_new);
 
 static void idr_remove_warning(int id)
 {
-        printk("idr_remove called for id=%d which is not allocated.\n", id);
+        printk(KERN_WARNING
+                "idr_remove called for id=%d which is not allocated.\n", id);
         dump_stack();
 }
 
@@ -334,6 +344,7 @@ static void sub_remove(struct idr *idp, int shift, int id)
         struct idr_layer *p = idp->top;
         struct idr_layer **pa[MAX_LEVEL];
         struct idr_layer ***paa = &pa[0];
+        struct idr_layer *to_free;
         int n;
 
         *paa = NULL;
@@ -349,13 +360,18 @@ static void sub_remove(struct idr *idp, int shift, int id)
         n = id & IDR_MASK;
         if (likely(p != NULL && test_bit(n, &p->bitmap))){
                 __clear_bit(n, &p->bitmap);
-                p->ary[n] = NULL;
+                rcu_assign_pointer(p->ary[n], NULL);
+                to_free = NULL;
                 while(*paa && ! --((**paa)->count)){
-                        free_layer(idp, **paa);
+                        if (to_free)
+                                free_layer(to_free);
+                        to_free = **paa;
                         **paa-- = NULL;
                 }
                 if (!*paa)
                         idp->layers = 0;
+                if (to_free)
+                        free_layer(to_free);
         } else
                 idr_remove_warning(id);
 }
@@ -368,22 +384,34 @@ static void sub_remove(struct idr *idp, int shift, int id)
 void idr_remove(struct idr *idp, int id)
 {
         struct idr_layer *p;
+        struct idr_layer *to_free;
 
         /* Mask off upper bits we don't use for the search. */
         id &= MAX_ID_MASK;
 
         sub_remove(idp, (idp->layers - 1) * IDR_BITS, id);
         if (idp->top && idp->top->count == 1 && (idp->layers > 1) &&
-            idp->top->ary[0]) {  // We can drop a layer
-
+            idp->top->ary[0]) {
+                /*
+                 * Single child at leftmost slot: we can shrink the tree.
+                 * This level is not needed anymore since when layers are
+                 * inserted, they are inserted at the top of the existing
+                 * tree.
+                 */
+                to_free = idp->top;
                 p = idp->top->ary[0];
-                idp->top->bitmap = idp->top->count = 0;
-                free_layer(idp, idp->top);
-                idp->top = p;
+                rcu_assign_pointer(idp->top, p);
                 --idp->layers;
+                to_free->bitmap = to_free->count = 0;
+                free_layer(to_free);
         }
         while (idp->id_free_cnt >= IDR_FREE_MAX) {
-                p = alloc_layer(idp);
+                p = get_from_free_list(idp);
+                /*
+                 * Note: we don't call the rcu callback here, since the only
+                 * layers that fall into the freelist are those that have been
+                 * preallocated.
+                 */
                 kmem_cache_free(idr_layer_cache, p);
         }
         return;
@@ -424,15 +452,13 @@ void idr_remove_all(struct idr *idp)
 
                 id += 1 << n;
                 while (n < fls(id)) {
-                        if (p) {
-                                memset(p, 0, sizeof *p);
-                                free_layer(idp, p);
-                        }
+                        if (p)
+                                free_layer(p);
                         n += IDR_BITS;
                         p = *--paa;
                 }
         }
-        idp->top = NULL;
+        rcu_assign_pointer(idp->top, NULL);
         idp->layers = 0;
 }
 EXPORT_SYMBOL(idr_remove_all);
@@ -444,7 +470,7 @@ EXPORT_SYMBOL(idr_remove_all);
 void idr_destroy(struct idr *idp)
 {
         while (idp->id_free_cnt) {
-                struct idr_layer *p = alloc_layer(idp);
+                struct idr_layer *p = get_from_free_list(idp);
                 kmem_cache_free(idr_layer_cache, p);
         }
 }
@@ -459,7 +485,8 @@ EXPORT_SYMBOL(idr_destroy);
  * return indicates that @id is not valid or you passed %NULL in
  * idr_get_new().
  *
- * The caller must serialize idr_find() vs idr_get_new() and idr_remove().
+ * This function can be called under rcu_read_lock(), given that the leaf
+ * pointers lifetimes are correctly managed.
  */
 void *idr_find(struct idr *idp, int id)
 {
@@ -467,7 +494,7 @@ void *idr_find(struct idr *idp, int id)
         struct idr_layer *p;
 
         n = idp->layers * IDR_BITS;
-        p = idp->top;
+        p = rcu_dereference(idp->top);
 
         /* Mask off upper bits we don't use for the search. */
         id &= MAX_ID_MASK;
@@ -477,7 +504,7 @@ void *idr_find(struct idr *idp, int id)
 
         while (n > 0 && p) {
                 n -= IDR_BITS;
-                p = p->ary[(id >> n) & IDR_MASK];
+                p = rcu_dereference(p->ary[(id >> n) & IDR_MASK]);
         }
         return((void *)p);
 }
@@ -510,7 +537,7 @@ int idr_for_each(struct idr *idp,
         struct idr_layer **paa = &pa[0];
 
         n = idp->layers * IDR_BITS;
-        p = idp->top;
+        p = rcu_dereference(idp->top);
         max = 1 << n;
 
         id = 0;
@@ -518,7 +545,7 @@ int idr_for_each(struct idr *idp,
                 while (n > 0 && p) {
                         n -= IDR_BITS;
                         *paa++ = p;
-                        p = p->ary[(id >> n) & IDR_MASK];
+                        p = rcu_dereference(p->ary[(id >> n) & IDR_MASK]);
                 }
 
                 if (p) {
@@ -548,7 +575,7 @@ EXPORT_SYMBOL(idr_for_each);
  * A -ENOENT return indicates that @id was not found.
  * A -EINVAL return indicates that @id was not within valid constraints.
  *
- * The caller must serialize vs idr_find(), idr_get_new(), and idr_remove().
+ * The caller must serialize with writers.
  */
 void *idr_replace(struct idr *idp, void *ptr, int id)
 {
@@ -574,13 +601,13 @@ void *idr_replace(struct idr *idp, void *ptr, int id)
                 return ERR_PTR(-ENOENT);
 
         old_p = p->ary[n];
-        p->ary[n] = ptr;
+        rcu_assign_pointer(p->ary[n], ptr);
 
         return old_p;
 }
 EXPORT_SYMBOL(idr_replace);
 
-static void idr_cache_ctor(struct kmem_cache *idr_layer_cache, void *idr_layer)
+static void idr_cache_ctor(void *idr_layer)
 {
         memset(idr_layer, 0, sizeof(struct idr_layer));
 }
@@ -694,12 +721,8 @@ int ida_get_new_above(struct ida *ida, int starting_id, int *p_id)
  restart:
         /* get vacant slot */
         t = idr_get_empty_slot(&ida->idr, idr_id, pa);
-        if (t < 0) {
-                if (t == -1)
-                        return -EAGAIN;
-                else /* will be -3 */
-                        return -ENOSPC;
-        }
+        if (t < 0)
+                return _idr_rc_to_errno(t);
 
         if (t * IDA_BITMAP_BITS >= MAX_ID_BIT)
                 return -ENOSPC;
@@ -720,7 +743,8 @@ int ida_get_new_above(struct ida *ida, int starting_id, int *p_id)
                         return -EAGAIN;
 
                 memset(bitmap, 0, sizeof(struct ida_bitmap));
-                pa[0]->ary[idr_id & IDR_MASK] = (void *)bitmap;
+                rcu_assign_pointer(pa[0]->ary[idr_id & IDR_MASK],
+                                (void *)bitmap);
                 pa[0]->count++;
         }
 
@@ -749,7 +773,7 @@ int ida_get_new_above(struct ida *ida, int starting_id, int *p_id)
          * allocation.
          */
         if (ida->idr.id_free_cnt || ida->free_bitmap) {
-                struct idr_layer *p = alloc_layer(&ida->idr);
+                struct idr_layer *p = get_from_free_list(&ida->idr);
                 if (p)
                         kmem_cache_free(idr_layer_cache, p);
         }
diff --git a/lib/inflate.c b/lib/inflate.c
index 9762294be062..1a8e8a978128 100644
--- a/lib/inflate.c
+++ b/lib/inflate.c
@@ -230,6 +230,45 @@ STATIC const ush mask_bits[] = {
 #define NEEDBITS(n) {while(k<(n)){b|=((ulg)NEXTBYTE())<<k;k+=8;}}
 #define DUMPBITS(n) {b>>=(n);k-=(n);}
 
+#ifndef NO_INFLATE_MALLOC
+/* A trivial malloc implementation, adapted from
+ *  malloc by Hannu Savolainen 1993 and Matthias Urlichs 1994
+ */
+
+static unsigned long malloc_ptr;
+static int malloc_count;
+
+static void *malloc(int size)
+{
+       void *p;
+
+       if (size < 0)
+                error("Malloc error");
+       if (!malloc_ptr)
+                malloc_ptr = free_mem_ptr;
+
+       malloc_ptr = (malloc_ptr + 3) & ~3;     /* Align */
+
+       p = (void *)malloc_ptr;
+       malloc_ptr += size;
+
+       if (free_mem_end_ptr && malloc_ptr >= free_mem_end_ptr)
+                error("Out of memory");
+
+       malloc_count++;
+       return p;
+}
+
+static void free(void *where)
+{
+       malloc_count--;
+       if (!malloc_count)
+                malloc_ptr = free_mem_ptr;
+}
+#else
+#define malloc(a) kmalloc(a, GFP_KERNEL)
+#define free(a) kfree(a)
+#endif
 
 /*
    Huffman code decoding is performed using a multi-level table lookup.
@@ -1045,7 +1084,6 @@ STATIC int INIT inflate(void)
   int e;                /* last block flag */
   int r;                /* result code */
   unsigned h;           /* maximum struct huft's malloc'ed */
-  void *ptr;
 
   /* initialize window, bit buffer */
   wp = 0;
@@ -1057,12 +1095,12 @@ STATIC int INIT inflate(void)
   h = 0;
   do {
     hufts = 0;
-    gzip_mark(&ptr);
-    if ((r = inflate_block(&e)) != 0) {
-      gzip_release(&ptr);           
-      return r;
-    }
-    gzip_release(&ptr);
+#ifdef ARCH_HAS_DECOMP_WDOG
+    arch_decomp_wdog();
+#endif
+    r = inflate_block(&e);
+    if (r)
+            return r;
     if (hufts > h)
       h = hufts;
   } while (!e);
diff --git a/lib/iomap.c b/lib/iomap.c
index 37a3ea4cac9f..d32229385151 100644
--- a/lib/iomap.c
+++ b/lib/iomap.c
@@ -40,8 +40,7 @@ static void bad_io_access(unsigned long port, const char *access)
         static int count = 10;
         if (count) {
                 count--;
-                printk(KERN_ERR "Bad IO access at port %#lx (%s)\n", port, access);
-                WARN_ON(1);
+                WARN(1, KERN_ERR "Bad IO access at port %#lx (%s)\n", port, access);
         }
 }
 
diff --git a/lib/kobject.c b/lib/kobject.c
index 744401571ed7..bd732ffebc85 100644
--- a/lib/kobject.c
+++ b/lib/kobject.c
@@ -164,9 +164,8 @@ static int kobject_add_internal(struct kobject *kobj)
                 return -ENOENT;
 
         if (!kobj->name || !kobj->name[0]) {
-                pr_debug("kobject: (%p): attempted to be registered with empty "
+                WARN(1, "kobject: (%p): attempted to be registered with empty "
                          "name!\n", kobj);
-                WARN_ON(1);
                 return -EINVAL;
         }
 
@@ -583,12 +582,10 @@ static void kobject_release(struct kref *kref)
 void kobject_put(struct kobject *kobj)
 {
         if (kobj) {
-                if (!kobj->state_initialized) {
-                        printk(KERN_WARNING "kobject: '%s' (%p): is not "
+                if (!kobj->state_initialized)
+                        WARN(1, KERN_WARNING "kobject: '%s' (%p): is not "
                                "initialized, yet kobject_put() is being "
                                "called.\n", kobject_name(kobj), kobj);
-                        WARN_ON(1);
-                }
                 kref_put(&kobj->kref, kobject_release);
         }
 }
diff --git a/lib/kobject_uevent.c b/lib/kobject_uevent.c
index 9f8d599459d1..3f914725bda8 100644
--- a/lib/kobject_uevent.c
+++ b/lib/kobject_uevent.c
@@ -285,8 +285,7 @@ int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
         int len;
 
         if (env->envp_idx >= ARRAY_SIZE(env->envp)) {
-                printk(KERN_ERR "add_uevent_var: too many keys\n");
-                WARN_ON(1);
+                WARN(1, KERN_ERR "add_uevent_var: too many keys\n");
                 return -ENOMEM;
         }
 
@@ -297,8 +296,7 @@ int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
         va_end(args);
 
         if (len >= (sizeof(env->buf) - env->buflen)) {
-                printk(KERN_ERR "add_uevent_var: buffer size too small\n");
-                WARN_ON(1);
+                WARN(1, KERN_ERR "add_uevent_var: buffer size too small\n");
                 return -ENOMEM;
         }
 
diff --git a/lib/list_debug.c b/lib/list_debug.c
index 4350ba9655bd..1a39f4e3ae1f 100644
--- a/lib/list_debug.c
+++ b/lib/list_debug.c
@@ -20,18 +20,14 @@ void __list_add(struct list_head *new,
                               struct list_head *prev,
                               struct list_head *next)
 {
-        if (unlikely(next->prev != prev)) {
-                printk(KERN_ERR "list_add corruption. next->prev should be "
-                        "prev (%p), but was %p. (next=%p).\n",
-                        prev, next->prev, next);
-                BUG();
-        }
-        if (unlikely(prev->next != next)) {
-                printk(KERN_ERR "list_add corruption. prev->next should be "
-                        "next (%p), but was %p. (prev=%p).\n",
-                        next, prev->next, prev);
-                BUG();
-        }
+        WARN(next->prev != prev,
+                "list_add corruption. next->prev should be "
+                "prev (%p), but was %p. (next=%p).\n",
+                prev, next->prev, next);
+        WARN(prev->next != next,
+                "list_add corruption. prev->next should be "
+                "next (%p), but was %p. (prev=%p).\n",
+                next, prev->next, prev);
         next->prev = new;
         new->next = next;
         new->prev = prev;
@@ -40,20 +36,6 @@ void __list_add(struct list_head *new,
 EXPORT_SYMBOL(__list_add);
 
 /**
- * list_add - add a new entry
- * @new: new entry to be added
- * @head: list head to add it after
- *
- * Insert a new entry after the specified head.
- * This is good for implementing stacks.
- */
-void list_add(struct list_head *new, struct list_head *head)
-{
-        __list_add(new, head, head->next);
-}
-EXPORT_SYMBOL(list_add);
-
-/**
  * list_del - deletes entry from list.
  * @entry: the element to delete from the list.
  * Note: list_empty on entry does not return true after this, the entry is
@@ -61,16 +43,12 @@ EXPORT_SYMBOL(list_add);
  */
 void list_del(struct list_head *entry)
 {
-        if (unlikely(entry->prev->next != entry)) {
-                printk(KERN_ERR "list_del corruption. prev->next should be %p, "
-                                "but was %p\n", entry, entry->prev->next);
-                BUG();
-        }
-        if (unlikely(entry->next->prev != entry)) {
-                printk(KERN_ERR "list_del corruption. next->prev should be %p, "
-                                "but was %p\n", entry, entry->next->prev);
-                BUG();
-        }
+        WARN(entry->prev->next != entry,
+                "list_del corruption. prev->next should be %p, "
+                "but was %p\n", entry, entry->prev->next);
+        WARN(entry->next->prev != entry,
+                "list_del corruption. next->prev should be %p, "
+                "but was %p\n", entry, entry->next->prev);
         __list_del(entry->prev, entry->next);
         entry->next = LIST_POISON1;
         entry->prev = LIST_POISON2;
diff --git a/lib/lzo/lzo1x_decompress.c b/lib/lzo/lzo1x_decompress.c
index 77f0f9b775a9..5dc6b29c1575 100644
--- a/lib/lzo/lzo1x_decompress.c
+++ b/lib/lzo/lzo1x_decompress.c
@@ -138,8 +138,7 @@ match:
                                         t += 31 + *ip++;
                                 }
                                 m_pos = op - 1;
-                                m_pos -= le16_to_cpu(get_unaligned(
-                                        (const unsigned short *)ip)) >> 2;
+                                m_pos -= get_unaligned_le16(ip) >> 2;
                                 ip += 2;
                         } else if (t >= 16) {
                                 m_pos = op;
@@ -157,8 +156,7 @@ match:
                                         }
                                         t += 7 + *ip++;
                                 }
-                                m_pos -= le16_to_cpu(get_unaligned(
-                                        (const unsigned short *)ip)) >> 2;
+                                m_pos -= get_unaligned_le16(ip) >> 2;
                                 ip += 2;
                                 if (m_pos == op)
                                         goto eof_found;
diff --git a/lib/plist.c b/lib/plist.c
index 3074a02272f3..d6c64a824e1d 100644
--- a/lib/plist.c
+++ b/lib/plist.c
@@ -31,12 +31,13 @@
 static void plist_check_prev_next(struct list_head *t, struct list_head *p,
                                   struct list_head *n)
 {
-        if (n->prev != p || p->next != n) {
-                printk("top: %p, n: %p, p: %p\n", t, t->next, t->prev);
-                printk("prev: %p, n: %p, p: %p\n", p, p->next, p->prev);
-                printk("next: %p, n: %p, p: %p\n", n, n->next, n->prev);
-                WARN_ON(1);
-        }
+        WARN(n->prev != p || p->next != n,
+                        "top: %p, n: %p, p: %p\n"
+                        "prev: %p, n: %p, p: %p\n"
+                        "next: %p, n: %p, p: %p\n",
+                         t, t->next, t->prev,
+                        p, p->next, p->prev,
+                        n, n->next, n->prev);
 }
 
 static void plist_check_list(struct list_head *top)
diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index 56ec21a7f73d..be86b32bc874 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -359,18 +359,17 @@ EXPORT_SYMBOL(radix_tree_insert);
  *      Returns:  the slot corresponding to the position @index in the
  *      radix tree @root. This is useful for update-if-exists operations.
  *
- *      This function cannot be called under rcu_read_lock, it must be
- *      excluded from writers, as must the returned slot for subsequent
- *      use by radix_tree_deref_slot() and radix_tree_replace slot.
- *      Caller must hold tree write locked across slot lookup and
- *      replace.
+ *      This function can be called under rcu_read_lock iff the slot is not
+ *      modified by radix_tree_replace_slot, otherwise it must be called
+ *      exclusive from other writers. Any dereference of the slot must be done
+ *      using radix_tree_deref_slot.
  */
 void **radix_tree_lookup_slot(struct radix_tree_root *root, unsigned long index)
 {
         unsigned int height, shift;
         struct radix_tree_node *node, **slot;
 
-        node = root->rnode;
+        node = rcu_dereference(root->rnode);
         if (node == NULL)
                 return NULL;
 
@@ -390,7 +389,7 @@ void **radix_tree_lookup_slot(struct radix_tree_root *root, unsigned long index)
         do {
                 slot = (struct radix_tree_node **)
                         (node->slots + ((index>>shift) & RADIX_TREE_MAP_MASK));
-                node = *slot;
+                node = rcu_dereference(*slot);
                 if (node == NULL)
                         return NULL;
 
@@ -667,7 +666,7 @@ unsigned long radix_tree_next_hole(struct radix_tree_root *root,
 EXPORT_SYMBOL(radix_tree_next_hole);
 
 static unsigned int
-__lookup(struct radix_tree_node *slot, void **results, unsigned long index,
+__lookup(struct radix_tree_node *slot, void ***results, unsigned long index,
         unsigned int max_items, unsigned long *next_index)
 {
         unsigned int nr_found = 0;
@@ -701,11 +700,9 @@ __lookup(struct radix_tree_node *slot, void **results, unsigned long index,
 
         /* Bottom level: grab some items */
         for (i = index & RADIX_TREE_MAP_MASK; i < RADIX_TREE_MAP_SIZE; i++) {
-                struct radix_tree_node *node;
                 index++;
-                node = slot->slots[i];
-                if (node) {
-                        results[nr_found++] = rcu_dereference(node);
+                if (slot->slots[i]) {
+                        results[nr_found++] = &(slot->slots[i]);
                         if (nr_found == max_items)
                                 goto out;
                 }
@@ -759,13 +756,22 @@ radix_tree_gang_lookup(struct radix_tree_root *root, void **results,
 
         ret = 0;
         while (ret < max_items) {
-                unsigned int nr_found;
+                unsigned int nr_found, slots_found, i;
                 unsigned long next_index;       /* Index of next search */
 
                 if (cur_index > max_index)
                         break;
-                nr_found = __lookup(node, results + ret, cur_index,
+                slots_found = __lookup(node, (void ***)results + ret, cur_index,
                                         max_items - ret, &next_index);
+                nr_found = 0;
+                for (i = 0; i < slots_found; i++) {
+                        struct radix_tree_node *slot;
+                        slot = *(((void ***)results)[ret + i]);
+                        if (!slot)
+                                continue;
+                        results[ret + nr_found] = rcu_dereference(slot);
+                        nr_found++;
+                }
                 ret += nr_found;
                 if (next_index == 0)
                         break;
@@ -776,12 +782,71 @@ radix_tree_gang_lookup(struct radix_tree_root *root, void **results,
 }
 EXPORT_SYMBOL(radix_tree_gang_lookup);
 
+/**
+ *      radix_tree_gang_lookup_slot - perform multiple slot lookup on radix tree
+ *      @root:          radix tree root
+ *      @results:       where the results of the lookup are placed
+ *      @first_index:   start the lookup from this key
+ *      @max_items:     place up to this many items at *results
+ *
+ *      Performs an index-ascending scan of the tree for present items.  Places
+ *      their slots at *@results and returns the number of items which were
+ *      placed at *@results.
+ *
+ *      The implementation is naive.
+ *
+ *      Like radix_tree_gang_lookup as far as RCU and locking goes. Slots must
+ *      be dereferenced with radix_tree_deref_slot, and if using only RCU
+ *      protection, radix_tree_deref_slot may fail requiring a retry.
+ */
+unsigned int
+radix_tree_gang_lookup_slot(struct radix_tree_root *root, void ***results,
+                        unsigned long first_index, unsigned int max_items)
+{
+        unsigned long max_index;
+        struct radix_tree_node *node;
+        unsigned long cur_index = first_index;
+        unsigned int ret;
+
+        node = rcu_dereference(root->rnode);
+        if (!node)
+                return 0;
+
+        if (!radix_tree_is_indirect_ptr(node)) {
+                if (first_index > 0)
+                        return 0;
+                results[0] = (void **)&root->rnode;
+                return 1;
+        }
+        node = radix_tree_indirect_to_ptr(node);
+
+        max_index = radix_tree_maxindex(node->height);
+
+        ret = 0;
+        while (ret < max_items) {
+                unsigned int slots_found;
+                unsigned long next_index;       /* Index of next search */
+
+                if (cur_index > max_index)
+                        break;
+                slots_found = __lookup(node, results + ret, cur_index,
+                                        max_items - ret, &next_index);
+                ret += slots_found;
+                if (next_index == 0)
+                        break;
+                cur_index = next_index;
+        }
+
+        return ret;
+}
+EXPORT_SYMBOL(radix_tree_gang_lookup_slot);
+
 /*
  * FIXME: the two tag_get()s here should use find_next_bit() instead of
  * open-coding the search.
  */
 static unsigned int
-__lookup_tag(struct radix_tree_node *slot, void **results, unsigned long index,
+__lookup_tag(struct radix_tree_node *slot, void ***results, unsigned long index,
         unsigned int max_items, unsigned long *next_index, unsigned int tag)
 {
         unsigned int nr_found = 0;
@@ -811,11 +876,9 @@ __lookup_tag(struct radix_tree_node *slot, void **results, unsigned long index,
                         unsigned long j = index & RADIX_TREE_MAP_MASK;
 
                         for ( ; j < RADIX_TREE_MAP_SIZE; j++) {
-                                struct radix_tree_node *node;
                                 index++;
                                 if (!tag_get(slot, tag, j))
                                         continue;
-                                node = slot->slots[j];
                                 /*
                                  * Even though the tag was found set, we need to
                                  * recheck that we have a non-NULL node, because
@@ -826,9 +889,8 @@ __lookup_tag(struct radix_tree_node *slot, void **results, unsigned long index,
                                  * lookup ->slots[x] without a lock (ie. can't
                                  * rely on its value remaining the same).
                                  */
-                                if (node) {
-                                        node = rcu_dereference(node);
-                                        results[nr_found++] = node;
+                                if (slot->slots[j]) {
+                                        results[nr_found++] = &(slot->slots[j]);
                                         if (nr_found == max_items)
                                                 goto out;
                                 }
@@ -887,13 +949,22 @@ radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results,
 
         ret = 0;
         while (ret < max_items) {
-                unsigned int nr_found;
+                unsigned int nr_found, slots_found, i;
                 unsigned long next_index;       /* Index of next search */
 
                 if (cur_index > max_index)
                         break;
-                nr_found = __lookup_tag(node, results + ret, cur_index,
-                                        max_items - ret, &next_index, tag);
+                slots_found = __lookup_tag(node, (void ***)results + ret,
+                                cur_index, max_items - ret, &next_index, tag);
+                nr_found = 0;
+                for (i = 0; i < slots_found; i++) {
+                        struct radix_tree_node *slot;
+                        slot = *(((void ***)results)[ret + i]);
+                        if (!slot)
+                                continue;
+                        results[ret + nr_found] = rcu_dereference(slot);
+                        nr_found++;
+                }
                 ret += nr_found;
                 if (next_index == 0)
                         break;
@@ -905,6 +976,67 @@ radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results,
 EXPORT_SYMBOL(radix_tree_gang_lookup_tag);
 
 /**
+ *      radix_tree_gang_lookup_tag_slot - perform multiple slot lookup on a
+ *                                        radix tree based on a tag
+ *      @root:          radix tree root
+ *      @results:       where the results of the lookup are placed
+ *      @first_index:   start the lookup from this key
+ *      @max_items:     place up to this many items at *results
+ *      @tag:           the tag index (< RADIX_TREE_MAX_TAGS)
+ *
+ *      Performs an index-ascending scan of the tree for present items which
+ *      have the tag indexed by @tag set.  Places the slots at *@results and
+ *      returns the number of slots which were placed at *@results.
+ */
+unsigned int
+radix_tree_gang_lookup_tag_slot(struct radix_tree_root *root, void ***results,
+                unsigned long first_index, unsigned int max_items,
+                unsigned int tag)
+{
+        struct radix_tree_node *node;
+        unsigned long max_index;
+        unsigned long cur_index = first_index;
+        unsigned int ret;
+
+        /* check the root's tag bit */
+        if (!root_tag_get(root, tag))
+                return 0;
+
+        node = rcu_dereference(root->rnode);
+        if (!node)
+                return 0;
+
+        if (!radix_tree_is_indirect_ptr(node)) {
+                if (first_index > 0)
+                        return 0;
+                results[0] = (void **)&root->rnode;
+                return 1;
+        }
+        node = radix_tree_indirect_to_ptr(node);
+
+        max_index = radix_tree_maxindex(node->height);
+
+        ret = 0;
+        while (ret < max_items) {
+                unsigned int slots_found;
+                unsigned long next_index;       /* Index of next search */
+
+                if (cur_index > max_index)
+                        break;
+                slots_found = __lookup_tag(node, results + ret,
+                                cur_index, max_items - ret, &next_index, tag);
+                ret += slots_found;
+                if (next_index == 0)
+                        break;
+                cur_index = next_index;
+        }
+
+        return ret;
+}
+EXPORT_SYMBOL(radix_tree_gang_lookup_tag_slot);
+
+
+/**
  *      radix_tree_shrink    -    shrink height of a radix tree to minimal
  *      @root           radix tree root
  */
@@ -1051,7 +1183,7 @@ int radix_tree_tagged(struct radix_tree_root *root, unsigned int tag)
 EXPORT_SYMBOL(radix_tree_tagged);
 
 static void
-radix_tree_node_ctor(struct kmem_cache *cachep, void *node)
+radix_tree_node_ctor(void *node)
 {
         memset(node, 0, sizeof(struct radix_tree_node));
 }
diff --git a/lib/ratelimit.c b/lib/ratelimit.c
index 485e3040dcd4..35136671b215 100644
--- a/lib/ratelimit.c
+++ b/lib/ratelimit.c
@@ -3,6 +3,9 @@
  *
  * Isolated from kernel/printk.c by Dave Young <hidave.darkstar@gmail.com>
  *
+ * 2008-05-01 rewrite the function and use a ratelimit_state data struct as
+ * parameter. Now every user can use their own standalone ratelimit_state.
+ *
  * This file is released under the GPLv2.
  *
  */
@@ -11,41 +14,43 @@
 #include <linux/jiffies.h>
 #include <linux/module.h>
 
+static DEFINE_SPINLOCK(ratelimit_lock);
+static unsigned long flags;
+
 /*
  * __ratelimit - rate limiting
- * @ratelimit_jiffies: minimum time in jiffies between two callbacks
- * @ratelimit_burst: number of callbacks we do before ratelimiting
+ * @rs: ratelimit_state data
  *
- * This enforces a rate limit: not more than @ratelimit_burst callbacks
- * in every ratelimit_jiffies
+ * This enforces a rate limit: not more than @rs->ratelimit_burst callbacks
+ * in every @rs->ratelimit_jiffies
  */
-int __ratelimit(int ratelimit_jiffies, int ratelimit_burst)
+int __ratelimit(struct ratelimit_state *rs)
 {
-        static DEFINE_SPINLOCK(ratelimit_lock);
-        static unsigned toks = 10 * 5 * HZ;
-        static unsigned long last_msg;
-        static int missed;
-        unsigned long flags;
-        unsigned long now = jiffies;
+        if (!rs->interval)
+                return 1;
 
         spin_lock_irqsave(&ratelimit_lock, flags);
-        toks += now - last_msg;
-        last_msg = now;
-        if (toks > (ratelimit_burst * ratelimit_jiffies))
-                toks = ratelimit_burst * ratelimit_jiffies;
-        if (toks >= ratelimit_jiffies) {
-                int lost = missed;
+        if (!rs->begin)
+                rs->begin = jiffies;
 
-                missed = 0;
-                toks -= ratelimit_jiffies;
-                spin_unlock_irqrestore(&ratelimit_lock, flags);
-                if (lost)
-                        printk(KERN_WARNING "%s: %d messages suppressed\n",
-                                __func__, lost);
-                return 1;
+        if (time_is_before_jiffies(rs->begin + rs->interval)) {
+                if (rs->missed)
+                        printk(KERN_WARNING "%s: %d callbacks suppressed\n",
+                                __func__, rs->missed);
+                rs->begin = 0;
+                rs->printed = 0;
+                rs->missed = 0;
         }
-        missed++;
+        if (rs->burst && rs->burst > rs->printed)
+                goto print;
+
+        rs->missed++;
         spin_unlock_irqrestore(&ratelimit_lock, flags);
         return 0;
+
+print:
+        rs->printed++;
+        spin_unlock_irqrestore(&ratelimit_lock, flags);
+        return 1;
 }
 EXPORT_SYMBOL(__ratelimit);
diff --git a/lib/show_mem.c b/lib/show_mem.c
new file mode 100644
index 000000000000..238e72a18ce1
--- /dev/null
+++ b/lib/show_mem.c
@@ -0,0 +1,63 @@
+/*
+ * Generic show_mem() implementation
+ *
+ * Copyright (C) 2008 Johannes Weiner <hannes@saeurebad.de>
+ * All code subject to the GPL version 2.
+ */
+
+#include <linux/mm.h>
+#include <linux/nmi.h>
+#include <linux/quicklist.h>
+
+void show_mem(void)
+{
+        pg_data_t *pgdat;
+        unsigned long total = 0, reserved = 0, shared = 0,
+                nonshared = 0, highmem = 0;
+
+        printk(KERN_INFO "Mem-Info:\n");
+        show_free_areas();
+
+        for_each_online_pgdat(pgdat) {
+                unsigned long i, flags;
+
+                pgdat_resize_lock(pgdat, &flags);
+                for (i = 0; i < pgdat->node_spanned_pages; i++) {
+                        struct page *page;
+                        unsigned long pfn = pgdat->node_start_pfn + i;
+
+                        if (unlikely(!(i % MAX_ORDER_NR_PAGES)))
+                                touch_nmi_watchdog();
+
+                        if (!pfn_valid(pfn))
+                                continue;
+
+                        page = pfn_to_page(pfn);
+
+                        if (PageHighMem(page))
+                                highmem++;
+
+                        if (PageReserved(page))
+                                reserved++;
+                        else if (page_count(page) == 1)
+                                nonshared++;
+                        else if (page_count(page) > 1)
+                                shared += page_count(page) - 1;
+
+                        total++;
+                }
+                pgdat_resize_unlock(pgdat, &flags);
+        }
+
+        printk(KERN_INFO "%lu pages RAM\n", total);
+#ifdef CONFIG_HIGHMEM
+        printk(KERN_INFO "%lu pages HighMem\n", highmem);
+#endif
+        printk(KERN_INFO "%lu pages reserved\n", reserved);
+        printk(KERN_INFO "%lu pages shared\n", shared);
+        printk(KERN_INFO "%lu pages non-shared\n", nonshared);
+#ifdef CONFIG_QUICKLIST
+        printk(KERN_INFO "%lu pages in pagetable cache\n",
+                quicklist_total_size());
+#endif
+}
diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index d568894df8cc..977edbdbc1de 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -492,7 +492,7 @@ swiotlb_alloc_coherent(struct device *hwdev, size_t size,
                  */
                 dma_addr_t handle;
                 handle = swiotlb_map_single(NULL, NULL, size, DMA_FROM_DEVICE);
-                if (swiotlb_dma_mapping_error(handle))
+                if (swiotlb_dma_mapping_error(hwdev, handle))
                         return NULL;
 
                 ret = bus_to_virt(handle);
@@ -824,7 +824,7 @@ swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg,
 }
 
 int
-swiotlb_dma_mapping_error(dma_addr_t dma_addr)
+swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t dma_addr)
 {
         return (dma_addr == virt_to_bus(io_tlb_overflow_buffer));
 }
diff --git a/lib/syscall.c b/lib/syscall.c
new file mode 100644
index 000000000000..a4f7067f72fa
--- /dev/null
+++ b/lib/syscall.c
@@ -0,0 +1,75 @@
+#include <linux/ptrace.h>
+#include <linux/sched.h>
+#include <linux/module.h>
+#include <asm/syscall.h>
+
+static int collect_syscall(struct task_struct *target, long *callno,
+                           unsigned long args[6], unsigned int maxargs,
+                           unsigned long *sp, unsigned long *pc)
+{
+        struct pt_regs *regs = task_pt_regs(target);
+        if (unlikely(!regs))
+                return -EAGAIN;
+
+        *sp = user_stack_pointer(regs);
+        *pc = instruction_pointer(regs);
+
+        *callno = syscall_get_nr(target, regs);
+        if (*callno != -1L && maxargs > 0)
+                syscall_get_arguments(target, regs, 0, maxargs, args);
+
+        return 0;
+}
+
+/**
+ * task_current_syscall - Discover what a blocked task is doing.
+ * @target:             thread to examine
+ * @callno:             filled with system call number or -1
+ * @args:               filled with @maxargs system call arguments
+ * @maxargs:            number of elements in @args to fill
+ * @sp:                 filled with user stack pointer
+ * @pc:                 filled with user PC
+ *
+ * If @target is blocked in a system call, returns zero with *@callno
+ * set to the the call's number and @args filled in with its arguments.
+ * Registers not used for system call arguments may not be available and
+ * it is not kosher to use &struct user_regset calls while the system
+ * call is still in progress.  Note we may get this result if @target
+ * has finished its system call but not yet returned to user mode, such
+ * as when it's stopped for signal handling or syscall exit tracing.
+ *
+ * If @target is blocked in the kernel during a fault or exception,
+ * returns zero with *@callno set to -1 and does not fill in @args.
+ * If so, it's now safe to examine @target using &struct user_regset
+ * get() calls as long as we're sure @target won't return to user mode.
+ *
+ * Returns -%EAGAIN if @target does not remain blocked.
+ *
+ * Returns -%EINVAL if @maxargs is too large (maximum is six).
+ */
+int task_current_syscall(struct task_struct *target, long *callno,
+                         unsigned long args[6], unsigned int maxargs,
+                         unsigned long *sp, unsigned long *pc)
+{
+        long state;
+        unsigned long ncsw;
+
+        if (unlikely(maxargs > 6))
+                return -EINVAL;
+
+        if (target == current)
+                return collect_syscall(target, callno, args, maxargs, sp, pc);
+
+        state = target->state;
+        if (unlikely(!state))
+                return -EAGAIN;
+
+        ncsw = wait_task_inactive(target, state);
+        if (unlikely(!ncsw) ||
+            unlikely(collect_syscall(target, callno, args, maxargs, sp, pc)) ||
+            unlikely(wait_task_inactive(target, state) != ncsw))
+                return -EAGAIN;
+
+        return 0;
+}
+EXPORT_SYMBOL_GPL(task_current_syscall);