2.6.24

 block

diff --git a/block/blktrace.c b/block/blktrace.c
index 20fa034..9b4da4a 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)
@@ -202,6 +201,7 @@ static void blk_remove_tree(struct dentry *dir)
 static struct dentry *blk_create_tree(const char *blk_name)
 {
    struct dentry *dir = NULL;
+   int created = 0;
 
    mutex_lock(&blk_tree_mutex);
 
@@ -209,13 +209,17 @@ static struct dentry *blk_create_tree(const char *blk_name)
       blk_tree_root = debugfs_create_dir("block", NULL);
       if (!blk_tree_root)
          goto err;
+      created = 1;
    }
 
    dir = debugfs_create_dir(blk_name, blk_tree_root);
    if (dir)
       root_users++;
-   else
-      blk_remove_root();
+   else {
+      /* Delete root only if we created it */
+      if (created)
+         blk_remove_root();
+   }
 
 err:
    mutex_unlock(&blk_tree_mutex);
@@ -312,33 +316,26 @@ static struct rchan_callbacks blk_relay_callbacks = {
 /*
  * Setup everything required to start tracing
  */
-static int blk_trace_setup(struct request_queue *q, struct block_device *bdev,
-            char __user *arg)
+int do_blk_trace_setup(struct request_queue *q, struct block_device *bdev,
+         struct blk_user_trace_setup *buts)
 {
-   struct blk_user_trace_setup buts;
    struct blk_trace *old_bt, *bt = NULL;
    struct dentry *dir = NULL;
    char b[BDEVNAME_SIZE];
    int ret, i;
 
-   if (copy_from_user(&buts, arg, sizeof(buts)))
-      return -EFAULT;
-
-   if (!buts.buf_size || !buts.buf_nr)
+   if (!buts->buf_size || !buts->buf_nr)
       return -EINVAL;
 
-   strcpy(buts.name, bdevname(bdev, b));
+   strcpy(buts->name, bdevname(bdev, b));
 
    /*
     * some device names have larger paths - convert the slashes
     * to underscores for this to work as expected
     */
-   for (i = 0; i < strlen(buts.name); i++)
-      if (buts.name[i] == '/')
-         buts.name[i] = '_';
-
-   if (copy_to_user(arg, &buts, sizeof(buts)))
-      return -EFAULT;
+   for (i = 0; i < strlen(buts->name); i++)
+      if (buts->name[i] == '/')
+         buts->name[i] = '_';
 
    ret = -ENOMEM;
    bt = kzalloc(sizeof(*bt), GFP_KERNEL);
@@ -350,7 +347,7 @@ static int blk_trace_setup(struct request_queue *q, struct block_device *bdev,
       goto err;
 
    ret = -ENOENT;
-   dir = blk_create_tree(buts.name);
+   dir = blk_create_tree(buts->name);
    if (!dir)
       goto err;
 
@@ -363,20 +360,21 @@ static int blk_trace_setup(struct request_queue *q, struct block_device *bdev,
    if (!bt->dropped_file)
       goto err;
 
-   bt->rchan = relay_open("trace", dir, buts.buf_size, buts.buf_nr, &blk_relay_callbacks, bt);
+   bt->rchan = relay_open("trace", dir, buts->buf_size,
+            buts->buf_nr, &blk_relay_callbacks, bt);
    if (!bt->rchan)
       goto err;
 
-   bt->act_mask = buts.act_mask;
+   bt->act_mask = buts->act_mask;
    if (!bt->act_mask)
       bt->act_mask = (u16) -1;
 
-   bt->start_lba = buts.start_lba;
-   bt->end_lba = buts.end_lba;
+   bt->start_lba = buts->start_lba;
+   bt->end_lba = buts->end_lba;
    if (!bt->end_lba)
       bt->end_lba = -1ULL;
 
-   bt->pid = buts.pid;
+   bt->pid = buts->pid;
    bt->trace_state = Blktrace_setup;
 
    ret = -EBUSY;
@@ -401,6 +399,26 @@ err:
    return ret;
 }
 
+static int blk_trace_setup(struct request_queue *q, struct block_device *bdev,
+            char __user *arg)
+{
+   struct blk_user_trace_setup buts;
+   int ret;
+
+   ret = copy_from_user(&buts, arg, sizeof(buts));
+   if (ret)
+      return -EFAULT;
+
+   ret = do_blk_trace_setup(q, bdev, &buts);
+   if (ret)
+      return ret;
+
+   if (copy_to_user(arg, &buts, sizeof(buts)))
+      return -EFAULT;
+
+   return 0;
+}
+
 static int blk_trace_startstop(struct request_queue *q, int start)
 {
    struct blk_trace *bt;
@@ -486,77 +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, 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);
-