[PATCH] mutex subsystem, semaphore to completion: drivers/block/loop.c

convert the block loop device from semaphores to completions.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index bed9ad7..8647290 100644 (file)
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -527,12 +527,12 @@ static int loop_make_request(request_queue_t *q, struct bio *old_bio)
        lo->lo_pending++;
        loop_add_bio(lo, old_bio);
        spin_unlock_irq(&lo->lo_lock);
-       up(&lo->lo_bh_mutex);
+       complete(&lo->lo_bh_done);
        return 0;
 
 out:
        if (lo->lo_pending == 0)
-               up(&lo->lo_bh_mutex);
+               complete(&lo->lo_bh_done);
        spin_unlock_irq(&lo->lo_lock);
        bio_io_error(old_bio, old_bio->bi_size);
        return 0;
@@ -593,23 +593,20 @@ static int loop_thread(void *data)
        lo->lo_pending = 1;
 
        /*
-        * up sem, we are running
+        * complete it, we are running
         */
-       up(&lo->lo_sem);
+       complete(&lo->lo_done);
 
        for (;;) {
                int pending;
 
-               /*
-                * interruptible just to not contribute to load avg
-                */
-               if (down_interruptible(&lo->lo_bh_mutex))
+               if (wait_for_completion_interruptible(&lo->lo_bh_done))
                        continue;
 
                spin_lock_irq(&lo->lo_lock);
 
                /*
-                * could be upped because of tear-down, not pending work
+                * could be completed because of tear-down, not pending work
                 */
                if (unlikely(!lo->lo_pending)) {
                        spin_unlock_irq(&lo->lo_lock);
@@ -632,7 +629,7 @@ static int loop_thread(void *data)
                        break;
        }
 
-       up(&lo->lo_sem);
+       complete(&lo->lo_done);
        return 0;
 }
 
@@ -843,7 +840,7 @@ static int loop_set_fd(struct loop_device *lo, struct file *lo_file,
        set_blocksize(bdev, lo_blocksize);
 
        kernel_thread(loop_thread, lo, CLONE_KERNEL);
-       down(&lo->lo_sem);
+       wait_for_completion(&lo->lo_done);
        return 0;
 
  out_putf:
@@ -909,10 +906,10 @@ static int loop_clr_fd(struct loop_device *lo, struct block_device *bdev)
        lo->lo_state = Lo_rundown;
        lo->lo_pending--;
        if (!lo->lo_pending)
-               up(&lo->lo_bh_mutex);
+               complete(&lo->lo_bh_done);
        spin_unlock_irq(&lo->lo_lock);
 
-       down(&lo->lo_sem);
+       wait_for_completion(&lo->lo_done);
 
        lo->lo_backing_file = NULL;
 
@@ -1289,8 +1286,8 @@ static int __init loop_init(void)
                if (!lo->lo_queue)
                        goto out_mem4;
                init_MUTEX(&lo->lo_ctl_mutex);
-               init_MUTEX_LOCKED(&lo->lo_sem);
-               init_MUTEX_LOCKED(&lo->lo_bh_mutex);
+               init_completion(&lo->lo_done);
+               init_completion(&lo->lo_bh_done);
                lo->lo_number = i;
                spin_lock_init(&lo->lo_lock);
                disk->major = LOOP_MAJOR;

diff --git a/include/linux/loop.h b/include/linux/loop.h
index 40f63c9..f965067 100644 (file)
--- a/include/linux/loop.h
+++ b/include/linux/loop.h
@@ -58,9 +58,9 @@ struct loop_device {
        struct bio              *lo_bio;
        struct bio              *lo_biotail;
        int                     lo_state;
-       struct semaphore        lo_sem;
+       struct completion       lo_done;
+       struct completion       lo_bh_done;
        struct semaphore        lo_ctl_mutex;
-       struct semaphore        lo_bh_mutex;
        int                     lo_pending;
 
        request_queue_t         *lo_queue;