diff options
| author |   NeilBrown <neilb@suse.com> | 2017-06-18 14:38:58 +1000 |
|---|---|---|
| committer |   Jens Axboe <axboe@kernel.dk> | 2017-06-18 12:40:59 -0600 |
| commit | f856dc36b6db4cbe757f95787136087fb37af2af (patch) | |
| tree | 8aa36bbe56deb1622e4042803fa12d4babd5a632 /drivers/block | |
| parent | block: Improvements to bounce-buffer handling (diff) | |
| download | linux-dev-f856dc36b6db4cbe757f95787136087fb37af2af.tar.xz linux-dev-f856dc36b6db4cbe757f95787136087fb37af2af.zip | |
rbd: use bio_clone_fast() instead of bio_clone()
bio_clone() makes a copy of the bi_io_vec, but rbd never changes that,
so there is no need for a copy.
bio_clone_fast() can be used instead, which avoids making the copy.
This requires that we provide a bio_set. bio_clone() uses fs_bio_set,
but it isn't, in general, safe to use the same bio_set at different
levels of the stack, as that can lead to deadlocks. As filesystems
use fs_bio_set, block devices shouldn't.
As rbd never stacks, it is safe to have a single global bio_set for
all rbd devices to use. So allocate that when the module is
initialised, and use it with bio_clone_fast().
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/block')
| -rw-r--r-- | drivers/block/rbd.c | 16 |
1 files changed, 15 insertions, 1 deletions
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c index 5420bc40c544..b008b6a98098 100644 --- a/drivers/block/rbd.c +++ b/drivers/block/rbd.c @@ -442,6 +442,8 @@ static DEFINE_SPINLOCK(rbd_client_list_lock); static struct kmem_cache *rbd_img_request_cache; static struct kmem_cache *rbd_obj_request_cache; +static struct bio_set *rbd_bio_clone; + static int rbd_major; static DEFINE_IDA(rbd_dev_id_ida); @@ -1363,7 +1365,7 @@ static struct bio *bio_clone_range(struct bio *bio_src, { struct bio *bio; - bio = bio_clone(bio_src, gfpmask); + bio = bio_clone_fast(bio_src, gfpmask, rbd_bio_clone); if (!bio) return NULL; /* ENOMEM */ @@ -6416,8 +6418,16 @@ static int rbd_slab_init(void) if (!rbd_obj_request_cache) goto out_err; + rbd_assert(!rbd_bio_clone); + rbd_bio_clone = bioset_create(BIO_POOL_SIZE, 0, 0); + if (!rbd_bio_clone) + goto out_err_clone; + return 0; +out_err_clone: + kmem_cache_destroy(rbd_obj_request_cache); + rbd_obj_request_cache = NULL; out_err: kmem_cache_destroy(rbd_img_request_cache); rbd_img_request_cache = NULL; @@ -6433,6 +6443,10 @@ static void rbd_slab_exit(void) rbd_assert(rbd_img_request_cache); kmem_cache_destroy(rbd_img_request_cache); rbd_img_request_cache = NULL; + + rbd_assert(rbd_bio_clone); + bioset_free(rbd_bio_clone); + rbd_bio_clone = NULL; } static int __init rbd_init(void) |