From: Ingo Molnar Convert the block loop device from semaphores to completions. Signed-off-by: Ingo Molnar Signed-off-by: Andrew Morton --- drivers/block/loop.c | 27 ++++++++++++--------------- include/linux/loop.h | 4 ++-- 2 files changed, 14 insertions(+), 17 deletions(-) diff -puN drivers/block/loop.c~mutex-subsystem-semaphore-to-completion-drivers-block-loopc drivers/block/loop.c --- 25/drivers/block/loop.c~mutex-subsystem-semaphore-to-completion-drivers-block-loopc Fri Jan 6 17:05:19 2006 +++ 25-akpm/drivers/block/loop.c Fri Jan 6 17:05:19 2006 @@ -527,12 +527,12 @@ static int loop_make_request(request_que 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_devic 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_devic 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 -puN include/linux/loop.h~mutex-subsystem-semaphore-to-completion-drivers-block-loopc include/linux/loop.h --- 25/include/linux/loop.h~mutex-subsystem-semaphore-to-completion-drivers-block-loopc Fri Jan 6 17:05:19 2006 +++ 25-akpm/include/linux/loop.h Fri Jan 6 17:05:19 2006 @@ -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; _