lkml.org 
[lkml]   [2012]   [Sep]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH v10 6/8] block: Kill bi_destructor
    Date
    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 <koverstreet@google.com>
    CC: Jens Axboe <axboe@kernel.dk>
    ---
    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(-)

    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 95c4935..b776cc9 100644
    --- a/block/blk-core.c
    +++ b/block/blk-core.c
    @@ -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;
    diff --git a/fs/bio.c b/fs/bio.c
    index 919ee9a..736ef12 100644
    --- a/fs/bio.c
    +++ b/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, 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);

    diff --git a/include/linux/bio.h b/include/linux/bio.h
    index 76f6c25..04944c9 100644
    --- a/include/linux/bio.h
    +++ b/include/linux/bio.h
    @@ -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;
    diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
    index 1b607c2..3eefbb2 100644
    --- a/include/linux/blk_types.h
    +++ b/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. This member
    --
    1.7.12


    \
     
     \ /
      Last update: 2012-09-07 01:21    [W:4.388 / U:0.184 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site