From 4254bba17d92d53822a56ebc2a0c1eb7e2a71155 Mon Sep 17 00:00:00 2001 From: Kent Overstreet Date: Thu, 6 Sep 2012 15:35:00 -0700 Subject: [PATCH 6/8] block: Kill bi_destructor Now that we've got generic code for freeing bios allocated from bio pools, this isn't needed anymore. This patch also makes bio_free() static, since without bi_destructor there should be no need for it to be called anywhere else. bio_free() is now only called from bio_put, so we can refactor those a bit - move some code from bio_put() to bio_free() and kill the redundant bio->bi_next = NULL. v5: Switch to BIO_KMALLOC_POOL ((void *)~0), per Boaz v6: BIO_KMALLOC_POOL now NULL, drop bio_free's EXPORT_SYMBOL v7: No #define BIO_KMALLOC_POOL anymore Signed-off-by: Kent Overstreet CC: Jens Axboe Signed-off-by: Jens Axboe --- Documentation/block/biodoc.txt | 5 --- block/blk-core.c | 2 - fs/bio.c | 64 ++++++++++++++++------------------------- include/linux/bio.h | 1 include/linux/blk_types.h | 3 - 5 files changed, 27 insertions(+), 48 deletions(-) Index: linux/Documentation/block/biodoc.txt =================================================================== --- linux.orig/Documentation/block/biodoc.txt +++ linux/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 poo 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 Index: linux/block/blk-core.c =================================================================== --- linux.orig/block/blk-core.c +++ linux/block/blk-core.c @@ -2809,7 +2809,7 @@ int blk_rq_prep_clone(struct request *rq free_and_out: if (bio) - bio_free(bio, bs); + bio_put(bio); blk_rq_unprep_clone(rq); return -ENOMEM; Index: linux/fs/bio.c =================================================================== --- linux.orig/fs/bio.c +++ linux/fs/bio.c @@ -233,26 +233,37 @@ fallback: return bvl; } -void bio_free(struct bio *bio, struct bio_set *bs) +static void __bio_free(struct bio *bio) { - void *p; - - if (bio_has_allocated_vec(bio)) - bvec_free_bs(bs, bio->bi_io_vec, BIO_POOL_IDX(bio)); + bio_disassociate_task(bio); if (bio_integrity(bio)) bio_integrity_free(bio); +} - /* - * If we have front padding, adjust the bio pointer before freeing - */ - p = bio; - if (bs->front_pad) +static void bio_free(struct bio *bio) +{ + struct bio_set *bs = bio->bi_pool; + void *p; + + __bio_free(bio); + + if (bs) { + if (bio_has_allocated_vec(bio)) + bvec_free_bs(bs, bio->bi_io_vec, BIO_POOL_IDX(bio)); + + /* + * If we have front padding, adjust the bio pointer before freeing + */ + p = bio; p -= bs->front_pad; - mempool_free(p, bs->bio_pool); + mempool_free(p, bs->bio_pool); + } else { + /* Bio was allocated by bio_kmalloc() */ + kfree(bio); + } } -EXPORT_SYMBOL(bio_free); void bio_init(struct bio *bio) { @@ -276,10 +287,7 @@ void bio_reset(struct bio *bio) { unsigned long flags = bio->bi_flags & (~0UL << BIO_RESET_BITS); - if (bio_integrity(bio)) - bio_integrity_free(bio); - - bio_disassociate_task(bio); + __bio_free(bio); memset(bio, 0, BIO_RESET_BYTES); bio->bi_flags = flags|(1 << BIO_UPTODATE); @@ -362,13 +370,6 @@ struct bio *bio_alloc(gfp_t gfp_mask, un } EXPORT_SYMBOL(bio_alloc); -static void bio_kmalloc_destructor(struct bio *bio) -{ - if (bio_integrity(bio)) - bio_integrity_free(bio); - kfree(bio); -} - /** * bio_kmalloc - allocate a bio for I/O using kmalloc() * @gfp_mask: the GFP_ mask given to the slab allocator @@ -395,7 +396,6 @@ struct bio *bio_kmalloc(gfp_t gfp_mask, 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; return bio; } @@ -431,20 +431,8 @@ void bio_put(struct bio *bio) /* * last put frees it */ - if (atomic_dec_and_test(&bio->bi_cnt)) { - bio_disassociate_task(bio); - bio->bi_next = NULL; - - /* - * This if statement is temporary - bi_pool is replacing - * bi_destructor, but bi_destructor will be taken out in another - * patch. - */ - if (bio->bi_pool) - bio_free(bio, bio->bi_pool); - else - bio->bi_destructor(bio); - } + if (atomic_dec_and_test(&bio->bi_cnt)) + bio_free(bio); } EXPORT_SYMBOL(bio_put); Index: linux/include/linux/bio.h =================================================================== --- linux.orig/include/linux/bio.h +++ linux/include/linux/bio.h @@ -216,7 +216,6 @@ extern struct bio *bio_alloc(gfp_t, unsi 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_endio(struct bio *, int); struct request_queue; Index: linux/include/linux/blk_types.h =================================================================== --- linux.orig/include/linux/blk_types.h +++ linux/include/linux/blk_types.h @@ -84,11 +84,8 @@ struct bio { struct bio_vec *bi_io_vec; /* the actual vec list */ - /* 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. 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