diff options
author | Kees Cook <keescook@chromium.org> | 2018-08-06 16:32:16 -0700 |
---|---|---|
committer | Jens Axboe <axboe@kernel.dk> | 2018-09-06 15:12:24 -0600 |
commit | 3d0e63754fa47d65edff172c1156f44b6fca5ca1 (patch) | |
tree | fd3d733cba29c446722002093870c065b7d5961b /drivers/block/drbd/drbd_worker.c | |
parent | ca16eb342ebedbf3bb1d8450048fe428895b0b65 (diff) | |
download | linux-3d0e63754fa47d65edff172c1156f44b6fca5ca1.tar.bz2 |
drbd: Convert from ahash to shash
In preparing to remove all stack VLA usage from the kernel[1], this
removes the discouraged use of AHASH_REQUEST_ON_STACK in favor of
the smaller SHASH_DESC_ON_STACK by converting from ahash-wrapped-shash
to direct shash. By removing a layer of indirection this both improves
performance and reduces stack usage. The stack allocation will be made
a fixed size in a later patch to the crypto subsystem.
The bulk of the lines in this change are simple s/ahash/shash/, but the
main logic differences are in drbd_csum_ee() and drbd_csum_bio(), which
externalizes the page walking with k(un)map_atomic() instead of using
scattergather.
[1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com
Acked-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/block/drbd/drbd_worker.c')
-rw-r--r-- | drivers/block/drbd/drbd_worker.c | 63 |
1 files changed, 32 insertions, 31 deletions
diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c index b8f77e83d456..c7ef48efe871 100644 --- a/drivers/block/drbd/drbd_worker.c +++ b/drivers/block/drbd/drbd_worker.c @@ -295,60 +295,61 @@ void drbd_request_endio(struct bio *bio) complete_master_bio(device, &m); } -void drbd_csum_ee(struct crypto_ahash *tfm, struct drbd_peer_request *peer_req, void *digest) +void drbd_csum_ee(struct crypto_shash *tfm, struct drbd_peer_request *peer_req, void *digest) { - AHASH_REQUEST_ON_STACK(req, tfm); - struct scatterlist sg; + SHASH_DESC_ON_STACK(desc, tfm); struct page *page = peer_req->pages; struct page *tmp; unsigned len; + void *src; - ahash_request_set_tfm(req, tfm); - ahash_request_set_callback(req, 0, NULL, NULL); + desc->tfm = tfm; + desc->flags = 0; - sg_init_table(&sg, 1); - crypto_ahash_init(req); + crypto_shash_init(desc); + src = kmap_atomic(page); while ((tmp = page_chain_next(page))) { /* all but the last page will be fully used */ - sg_set_page(&sg, page, PAGE_SIZE, 0); - ahash_request_set_crypt(req, &sg, NULL, sg.length); - crypto_ahash_update(req); + crypto_shash_update(desc, src, PAGE_SIZE); + kunmap_atomic(src); page = tmp; + src = kmap_atomic(page); } /* and now the last, possibly only partially used page */ len = peer_req->i.size & (PAGE_SIZE - 1); - sg_set_page(&sg, page, len ?: PAGE_SIZE, 0); - ahash_request_set_crypt(req, &sg, digest, sg.length); - crypto_ahash_finup(req); - ahash_request_zero(req); + crypto_shash_update(desc, src, len ?: PAGE_SIZE); + kunmap_atomic(src); + + crypto_shash_final(desc, digest); + shash_desc_zero(desc); } -void drbd_csum_bio(struct crypto_ahash *tfm, struct bio *bio, void *digest) +void drbd_csum_bio(struct crypto_shash *tfm, struct bio *bio, void *digest) { - AHASH_REQUEST_ON_STACK(req, tfm); - struct scatterlist sg; + SHASH_DESC_ON_STACK(desc, tfm); struct bio_vec bvec; struct bvec_iter iter; - ahash_request_set_tfm(req, tfm); - ahash_request_set_callback(req, 0, NULL, NULL); + desc->tfm = tfm; + desc->flags = 0; - sg_init_table(&sg, 1); - crypto_ahash_init(req); + crypto_shash_init(desc); bio_for_each_segment(bvec, bio, iter) { - sg_set_page(&sg, bvec.bv_page, bvec.bv_len, bvec.bv_offset); - ahash_request_set_crypt(req, &sg, NULL, sg.length); - crypto_ahash_update(req); + u8 *src; + + src = kmap_atomic(bvec.bv_page); + crypto_shash_update(desc, src + bvec.bv_offset, bvec.bv_len); + kunmap_atomic(src); + /* REQ_OP_WRITE_SAME has only one segment, * checksum the payload only once. */ if (bio_op(bio) == REQ_OP_WRITE_SAME) break; } - ahash_request_set_crypt(req, NULL, digest, 0); - crypto_ahash_final(req); - ahash_request_zero(req); + crypto_shash_final(desc, digest); + shash_desc_zero(desc); } /* MAYBE merge common code with w_e_end_ov_req */ @@ -367,7 +368,7 @@ static int w_e_send_csum(struct drbd_work *w, int cancel) if (unlikely((peer_req->flags & EE_WAS_ERROR) != 0)) goto out; - digest_size = crypto_ahash_digestsize(peer_device->connection->csums_tfm); + digest_size = crypto_shash_digestsize(peer_device->connection->csums_tfm); digest = kmalloc(digest_size, GFP_NOIO); if (digest) { sector_t sector = peer_req->i.sector; @@ -1205,7 +1206,7 @@ int w_e_end_csum_rs_req(struct drbd_work *w, int cancel) * a real fix would be much more involved, * introducing more locking mechanisms */ if (peer_device->connection->csums_tfm) { - digest_size = crypto_ahash_digestsize(peer_device->connection->csums_tfm); + digest_size = crypto_shash_digestsize(peer_device->connection->csums_tfm); D_ASSERT(device, digest_size == di->digest_size); digest = kmalloc(digest_size, GFP_NOIO); } @@ -1255,7 +1256,7 @@ int w_e_end_ov_req(struct drbd_work *w, int cancel) if (unlikely(cancel)) goto out; - digest_size = crypto_ahash_digestsize(peer_device->connection->verify_tfm); + digest_size = crypto_shash_digestsize(peer_device->connection->verify_tfm); digest = kmalloc(digest_size, GFP_NOIO); if (!digest) { err = 1; /* terminate the connection in case the allocation failed */ @@ -1327,7 +1328,7 @@ int w_e_end_ov_reply(struct drbd_work *w, int cancel) di = peer_req->digest; if (likely((peer_req->flags & EE_WAS_ERROR) == 0)) { - digest_size = crypto_ahash_digestsize(peer_device->connection->verify_tfm); + digest_size = crypto_shash_digestsize(peer_device->connection->verify_tfm); digest = kmalloc(digest_size, GFP_NOIO); if (digest) { drbd_csum_ee(peer_device->connection->verify_tfm, peer_req, digest); |