Thread (29 messages) 29 messages, 4 authors, 2012-08-29
STALE5045d
Revisions (7)
  1. v3 [diff vs current]
  2. v4 current
  3. v5 [diff vs current]
  4. v6 [diff vs current]
  5. v8 [diff vs current]
  6. v9 [diff vs current]
  7. v10 [diff vs current]

[PATCH v4 05/12] block: Kill bi_destructor

From: Kent Overstreet <hidden>
Date: 2012-07-24 20:12:02
Also in: dm-devel, lkml
Subsystem: block layer, documentation, drbd driver, filesystems (vfs and infrastructure), scsi target subsystem, the rest · Maintainers: Jens Axboe, Jonathan Corbet, Philipp Reisner, Lars Ellenberg, Christoph Böhmwalder, Alexander Viro, Christian Brauner, "Martin K. Petersen", Linus Torvalds

Now that we've got generic code for freeing bios allocated from bio
pools, this isn't needed anymore.

This also changes the semantics of bio_free() a bit - it now also frees
bios allocated by bio_kmalloc(). It's also no longer exported, as
without bi_destructor there should be no need for it to be called
anywhere else.

Signed-off-by: Kent Overstreet <redacted>
---
 Documentation/block/biodoc.txt      |    5 -----
 block/blk-core.c                    |    2 +-
 drivers/block/drbd/drbd_main.c      |   13 +------------
 drivers/target/target_core_iblock.c |    8 --------
 fs/bio.c                            |   32 +++++++++++++++++---------------
 include/linux/bio.h                 |    2 +-
 include/linux/blk_types.h           |    3 ---
 7 files changed, 20 insertions(+), 45 deletions(-)
diff --git a/Documentation/block/biodoc.txt b/Documentation/block/biodoc.txt
index e418dc0..8df5e8e 100644
--- a/Documentation/block/biodoc.txt
+++ b/Documentation/block/biodoc.txt
@@ -465,7 +465,6 @@ struct bio {
        bio_end_io_t	*bi_end_io;  /* bi_end_io (bio) */
        atomic_t		bi_cnt;	     /* pin count: free when it hits zero */
        void             *bi_private;
-       bio_destructor_t *bi_destructor; /* bi_destructor (bio) */
 };
 
 With this multipage bio design:
@@ -647,10 +646,6 @@ for a non-clone bio. There are the 6 pools setup for different size biovecs,
 so bio_alloc(gfp_mask, nr_iovecs) will allocate a vec_list of the
 given size from these slabs.
 
-The bi_destructor() routine takes into account the possibility of the bio
-having originated from a different source (see later discussions on
-n/w to block transfers and kvec_cb)
-
 The bio_get() routine may be used to hold an extra reference on a bio prior
 to i/o submission, if the bio fields are likely to be accessed after the
 i/o is issued (since the bio may otherwise get freed in case i/o completion
diff --git a/block/blk-core.c b/block/blk-core.c
index 93eb3e4..e9058c2 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -2794,7 +2794,7 @@ int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
 
 free_and_out:
 	if (bio)
-		bio_free(bio, bs);
+		bio_free(bio);
 	blk_rq_unprep_clone(rq);
 
 	return -ENOMEM;
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 920ede2..19bf632 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -161,23 +161,12 @@ static const struct block_device_operations drbd_ops = {
 	.release = drbd_release,
 };
 
-static void bio_destructor_drbd(struct bio *bio)
-{
-	bio_free(bio, drbd_md_io_bio_set);
-}
-
 struct bio *bio_alloc_drbd(gfp_t gfp_mask)
 {
-	struct bio *bio;
-
 	if (!drbd_md_io_bio_set)
 		return bio_alloc(gfp_mask, 1);
 
-	bio = bio_alloc_bioset(gfp_mask, 1, drbd_md_io_bio_set);
-	if (!bio)
-		return NULL;
-	bio->bi_destructor = bio_destructor_drbd;
-	return bio;
+	return bio_alloc_bioset(gfp_mask, 1, drbd_md_io_bio_set);
 }
 
 #ifdef __CHECKER__
diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c
index be65582..9338d0602 100644
--- a/drivers/target/target_core_iblock.c
+++ b/drivers/target/target_core_iblock.c
@@ -467,15 +467,7 @@ iblock_get_bio(struct se_cmd *cmd, sector_t lba, u32 sg_num)
 	}
 
 	bio->bi_bdev = ib_dev->ibd_bd;
-<<<<<<< HEAD
 	bio->bi_private = cmd;
-	bio->bi_destructor = iblock_bio_destructor;
-||||||| merged common ancestors
-	bio->bi_private = task;
-	bio->bi_destructor = iblock_bio_destructor;
-=======
-	bio->bi_private = task;
->>>>>>> block: Generalized bio pool freeing
 	bio->bi_end_io = &iblock_bio_done;
 	bio->bi_sector = lba;
 	return bio;
diff --git a/fs/bio.c b/fs/bio.c
index 252e253..a301071 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -56,6 +56,9 @@ static struct biovec_slab bvec_slabs[BIOVEC_NR_POOLS] __read_mostly = {
  */
 struct bio_set *fs_bio_set;
 
+/* Only used as a sentinal value */
+static struct bio_set bio_kmalloc_pool;
+
 /*
  * Our slab pool management
  */
@@ -232,10 +235,21 @@ fallback:
 	return bvl;
 }
 
-void bio_free(struct bio *bio, struct bio_set *bs)
+void bio_free(struct bio *bio)
 {
+	struct bio_set *bs = bio->bi_pool;
 	void *p;
 
+	BUG_ON(!bs);
+
+	if (bs == &bio_kmalloc_pool) {
+		/* Bio was allocated by bio_kmalloc() */
+		if (bio_integrity(bio))
+			bio_integrity_free(bio, fs_bio_set);
+		kfree(bio);
+		return;
+	}
+
 	if (bio_has_allocated_vec(bio))
 		bvec_free_bs(bs, bio->bi_io_vec, BIO_POOL_IDX(bio));
 
@@ -347,13 +361,6 @@ struct bio *bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
 }
 EXPORT_SYMBOL(bio_alloc);
 
-static void bio_kmalloc_destructor(struct bio *bio)
-{
-	if (bio_integrity(bio))
-		bio_integrity_free(bio, fs_bio_set);
-	kfree(bio);
-}
-
 /**
  * bio_kmalloc - allocate a bio for I/O using kmalloc()
  * @gfp_mask:   the GFP_ mask given to the slab allocator
@@ -380,7 +387,7 @@ struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned int nr_iovecs)
 	bio->bi_flags |= BIO_POOL_NONE << BIO_POOL_OFFSET;
 	bio->bi_max_vecs = nr_iovecs;
 	bio->bi_io_vec = bio->bi_inline_vecs;
-	bio->bi_destructor = bio_kmalloc_destructor;
+	bio->bi_pool = &bio_kmalloc_pool;
 
 	return bio;
 }
@@ -418,12 +425,7 @@ void bio_put(struct bio *bio)
 	 */
 	if (atomic_dec_and_test(&bio->bi_cnt)) {
 		bio_disassociate_task(bio);
-		bio->bi_next = NULL;
-
-		if (bio->bi_pool)
-			bio_free(bio, bio->bi_pool);
-		else
-			bio->bi_destructor(bio);
+		bio_free(bio);
 	}
 }
 EXPORT_SYMBOL(bio_put);
diff --git a/include/linux/bio.h b/include/linux/bio.h
index ba60319..393c87e 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -216,7 +216,7 @@ extern struct bio *bio_alloc(gfp_t, unsigned int);
 extern struct bio *bio_kmalloc(gfp_t, unsigned int);
 extern struct bio *bio_alloc_bioset(gfp_t, int, struct bio_set *);
 extern void bio_put(struct bio *);
-extern void bio_free(struct bio *, struct bio_set *);
+extern void bio_free(struct bio *);
 
 extern void bio_endio(struct bio *, int);
 struct request_queue;
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 40411e2..fa45a12 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -84,11 +84,8 @@ struct bio {
 	struct bio_integrity_payload *bi_integrity;  /* data integrity */
 #endif
 
-	/* If bi_pool is non NULL, bi_destructor is not called */
 	struct bio_set		*bi_pool;
 
-	bio_destructor_t	*bi_destructor;	/* destructor */
-
 	/*
 	 * We can inline a number of vecs at the end of the bio, to avoid
 	 * double allocations for a small number of bio_vecs. This member
-- 
1.7.7.3
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