3 files changed, 6 insertions, 81 deletions

diff --git a/block/blktrace.c b/block/blktrace.c
index 498a0a54a6aa..9b4da4ae3c7d 100644
--- a/block/blktrace.c
+++ b/block/blktrace.c
@@ -25,7 +25,6 @@
 #include <linux/time.h>
 #include <asm/uaccess.h>
 
-static DEFINE_PER_CPU(unsigned long long, blk_trace_cpu_offset) = { 0, };
 static unsigned int blktrace_seq __read_mostly = 1;
 
 /*
@@ -41,7 +40,7 @@ static void trace_note(struct blk_trace *bt, pid_t pid, int action,
                 const int cpu = smp_processor_id();
 
                 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
-                t->time = cpu_clock(cpu) - per_cpu(blk_trace_cpu_offset, cpu);
+                t->time = ktime_to_ns(ktime_get());
                 t->device = bt->dev;
                 t->action = action;
                 t->pid = pid;
@@ -159,7 +158,7 @@ void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
 
                 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
                 t->sequence = ++(*sequence);
-                t->time = cpu_clock(cpu) - per_cpu(blk_trace_cpu_offset, cpu);
+                t->time = ktime_to_ns(ktime_get());
                 t->sector = sector;
                 t->bytes = bytes;
                 t->action = what;
@@ -179,7 +178,7 @@ void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
 EXPORT_SYMBOL_GPL(__blk_add_trace);
 
 static struct dentry *blk_tree_root;
-static struct mutex blk_tree_mutex;
+static DEFINE_MUTEX(blk_tree_mutex);
 static unsigned int root_users;
 
 static inline void blk_remove_root(void)
@@ -505,77 +504,3 @@ void blk_trace_shutdown(struct request_queue *q)
                 blk_trace_remove(q);
         }
 }
-
-/*
- * Average offset over two calls to cpu_clock() with a gettimeofday()
- * in the middle
- */
-static void blk_check_time(unsigned long long *t, int this_cpu)
-{
-        unsigned long long a, b;
-        struct timeval tv;
-
-        a = cpu_clock(this_cpu);
-        do_gettimeofday(&tv);
-        b = cpu_clock(this_cpu);
-
-        *t = tv.tv_sec * 1000000000 + tv.tv_usec * 1000;
-        *t -= (a + b) / 2;
-}
-
-/*
- * calibrate our inter-CPU timings
- */
-static void blk_trace_check_cpu_time(void *data)
-{
-        unsigned long long *t;
-        int this_cpu = get_cpu();
-
-        t = &per_cpu(blk_trace_cpu_offset, this_cpu);
-
-        /*
-         * Just call it twice, hopefully the second call will be cache hot
-         * and a little more precise
-         */
-        blk_check_time(t, this_cpu);
-        blk_check_time(t, this_cpu);
-
-        put_cpu();
-}
-
-static void blk_trace_set_ht_offsets(void)
-{
-#if defined(CONFIG_SCHED_SMT)
-        int cpu, i;
-
-        /*
-         * now make sure HT siblings have the same time offset
-         */
-        preempt_disable();
-        for_each_online_cpu(cpu) {
-                unsigned long long *cpu_off, *sibling_off;
-
-                for_each_cpu_mask(i, per_cpu(cpu_sibling_map, cpu)) {
-                        if (i == cpu)
-                                continue;
-
-                        cpu_off = &per_cpu(blk_trace_cpu_offset, cpu);
-                        sibling_off = &per_cpu(blk_trace_cpu_offset, i);
-                        *sibling_off = *cpu_off;
-                }
-        }
-        preempt_enable();
-#endif
-}
-
-static __init int blk_trace_init(void)
-{
-        mutex_init(&blk_tree_mutex);
-        on_each_cpu(blk_trace_check_cpu_time, NULL, 1, 1);
-        blk_trace_set_ht_offsets();
-
-        return 0;
-}
-
-module_init(blk_trace_init);
-
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 56e23042728a..b8af22e610df 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -610,7 +610,7 @@ static int loop_thread(void *data)
 static int loop_switch(struct loop_device *lo, struct file *file)
 {
         struct switch_request w;
-        struct bio *bio = bio_alloc(GFP_KERNEL, 1);
+        struct bio *bio = bio_alloc(GFP_KERNEL, 0);
         if (!bio)
                 return -ENOMEM;
         init_completion(&w.wait);
diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index 416e000dfe81..e3ff21dbac53 100644
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -191,8 +191,8 @@ static inline void sg_chain(struct scatterlist *prv, unsigned int prv_nents,
         /*
          * offset and length are unused for chain entry.  Clear them.
          */
-        prv->offset = 0;
-        prv->length = 0;
+        prv[prv_nents - 1].offset = 0;
+        prv[prv_nents - 1].length = 0;
 
         /*
          * Set lowest bit to indicate a link pointer, and make sure to clear