Commit 4254bba1 authored by Kent Overstreet's avatar Kent Overstreet Committed by Jens Axboe
Browse files

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: default avatarKent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent ccc5c9ca

Documentation/block/biodoc.txt

+0 −5
Original line number Diff line number Diff line
@@ -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

block/blk-core.c

+1 −1
Original line number Diff line number Diff line
@@ -2807,7 +2807,7 @@ int blk_rq_prep_clone(struct request *rq, struct request *rq_src, 


free_and_out:

	if (bio)

		bio_free(bio, bs);

		bio_put(bio);

	blk_rq_unprep_clone(rq);



	return -ENOMEM;

fs/bio.c

+26 −38
Original line number Diff line number Diff line
@@ -233,26 +233,37 @@ fallback: 
	return bvl;

}



void bio_free(struct bio *bio, struct bio_set *bs)

static void __bio_free(struct bio *bio)

{

	bio_disassociate_task(bio);



	if (bio_integrity(bio))

		bio_integrity_free(bio);

}



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 (bio_integrity(bio))

		bio_integrity_free(bio);



		/*

		 * If we have front padding, adjust the bio pointer before freeing

		 */

		p = bio;

	if (bs->front_pad)

		p -= bs->front_pad;



		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, unsigned int nr_iovecs) 
}

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, 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;



	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);

include/linux/bio.h

+0 −1
Original line number Diff line number Diff line
@@ -216,7 +216,6 @@ 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_endio(struct bio *, int);

struct request_queue;

include/linux/blk_types.h

+0 −3
Original line number Diff line number Diff line
@@ -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. This member

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