loop: use BIO list management functions

Now that the bio list management stuff is generic, convert loop to use
bio lists instead of its own private bio list implementation.

Cc:  Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index ddae80825899ae0459bff4a8109d8fc3468868c3..9ca4bb01465714cb2bdb8bd8ef5ea4c59268893e 100644 (file)
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -511,11 +511,7 @@ out:
  */
 static void loop_add_bio(struct loop_device *lo, struct bio *bio)
 {
-       if (lo->lo_biotail) {
-               lo->lo_biotail->bi_next = bio;
-               lo->lo_biotail = bio;
-       } else
-               lo->lo_bio = lo->lo_biotail = bio;
+       bio_list_add(&lo->lo_bio_list, bio);
 }
 
 /*
@@ -523,16 +519,7 @@ static void loop_add_bio(struct loop_device *lo, struct bio *bio)
  */
 static struct bio *loop_get_bio(struct loop_device *lo)
 {
-       struct bio *bio;
-
-       if ((bio = lo->lo_bio)) {
-               if (bio == lo->lo_biotail)
-                       lo->lo_biotail = NULL;
-               lo->lo_bio = bio->bi_next;
-               bio->bi_next = NULL;
-       }
-
-       return bio;
+       return bio_list_pop(&lo->lo_bio_list);
 }
 
 static int loop_make_request(struct request_queue *q, struct bio *old_bio)
@@ -609,12 +596,13 @@ static int loop_thread(void *data)
 
        set_user_nice(current, -20);
 
-       while (!kthread_should_stop() || lo->lo_bio) {
+       while (!kthread_should_stop() || !bio_list_empty(&lo->lo_bio_list)) {
 
                wait_event_interruptible(lo->lo_event,
-                               lo->lo_bio || kthread_should_stop());
+                               !bio_list_empty(&lo->lo_bio_list) ||
+                               kthread_should_stop());
 
-               if (!lo->lo_bio)
+               if (bio_list_empty(&lo->lo_bio_list))
                        continue;
                spin_lock_irq(&lo->lo_lock);
                bio = loop_get_bio(lo);
@@ -841,7 +829,7 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode,
        lo->old_gfp_mask = mapping_gfp_mask(mapping);
        mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS));
 
-       lo->lo_bio = lo->lo_biotail = NULL;
+       bio_list_init(&lo->lo_bio_list);
 
        /*
         * set queue make_request_fn, and add limits based on lower level

diff --git a/include/linux/bio.h b/include/linux/bio.h
index 7b214fd672a2d923e56d8263d8c183d7dcf98b0e..f37ca8c726ba04b44674c7b88382c26fefa82325 100644 (file)
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -506,7 +506,7 @@ static inline int bio_has_data(struct bio *bio)
 }
 
 /*
- * BIO list managment for use by remapping drivers (e.g. DM or MD).
+ * BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
  *
  * A bio_list anchors a singly-linked list of bios chained through the bi_next
  * member of the bio.  The bio_list also caches the last list member to allow

diff --git a/include/linux/loop.h b/include/linux/loop.h
index 40725447f5e0e958ef58097636603f00ca3d04e0..66c194e2d9b9c072fc201b864506ae12c010112d 100644 (file)
--- a/include/linux/loop.h
+++ b/include/linux/loop.h
@@ -56,8 +56,7 @@ struct loop_device {
        gfp_t           old_gfp_mask;
 
        spinlock_t              lo_lock;
-       struct bio              *lo_bio;
-       struct bio              *lo_biotail;
+       struct bio_list         lo_bio_list;
        int                     lo_state;
        struct mutex            lo_ctl_mutex;
        struct task_struct      *lo_thread;