From b5e8ad92c3ac0b073bbf08ffd1a6a31d3449caae Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Tue, 15 Aug 2017 17:11:59 +0200 Subject: [PATCH] dm integrity: use init_completion instead of COMPLETION_INITIALIZER_ONSTACK The new lockdep support for completions causeed the stack usage in dm-integrity to explode, in case of write_journal from 504 bytes to 1120 (using arm gcc-7.1.1): drivers/md/dm-integrity.c: In function 'write_journal': drivers/md/dm-integrity.c:827:1: error: the frame size of 1120 bytes is larger than 1024 bytes [-Werror=frame-larger-than=] The problem is that not only the size of 'struct completion' grows significantly, but we end up having multiple copies of it on the stack when we assign it from a local variable after the initial declaration. COMPLETION_INITIALIZER_ONSTACK() is the right thing to use when we want to declare and initialize a completion on the stack. However, this driver doesn't do that and instead initializes the completion just before it is used. In this case, init_completion() does the same thing more efficiently, and drops the stack usage for the function above down to 496 bytes. While the other functions in this file are not bad enough to cause a warning, they benefit equally from the change, so I do the change across the entire file. In the one place where we reuse a completion, I picked the cheaper reinit_completion() over init_completion(). Fixes: cd8084f91c02 ("locking/lockdep: Apply crossrelease to completions") Signed-off-by: Arnd Bergmann Acked-by: Mikulas Patocka Acked-by: Mike Snitzer Signed-off-by: Mike Snitzer --- drivers/md/dm-integrity.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c index 2b32342..ac0d775 100644 --- a/drivers/md/dm-integrity.c +++ b/drivers/md/dm-integrity.c @@ -773,13 +773,13 @@ static void write_journal(struct dm_integrity_c *ic, unsigned commit_start, unsi unsigned i; io_comp.ic = ic; - io_comp.comp = COMPLETION_INITIALIZER_ONSTACK(io_comp.comp); + init_completion(&io_comp.comp); if (commit_start + commit_sections <= ic->journal_sections) { io_comp.in_flight = (atomic_t)ATOMIC_INIT(1); if (ic->journal_io) { crypt_comp_1.ic = ic; - crypt_comp_1.comp = COMPLETION_INITIALIZER_ONSTACK(crypt_comp_1.comp); + init_completion(&crypt_comp_1.comp); crypt_comp_1.in_flight = (atomic_t)ATOMIC_INIT(0); encrypt_journal(ic, true, commit_start, commit_sections, &crypt_comp_1); wait_for_completion_io(&crypt_comp_1.comp); @@ -795,18 +795,18 @@ static void write_journal(struct dm_integrity_c *ic, unsigned commit_start, unsi to_end = ic->journal_sections - commit_start; if (ic->journal_io) { crypt_comp_1.ic = ic; - crypt_comp_1.comp = COMPLETION_INITIALIZER_ONSTACK(crypt_comp_1.comp); + init_completion(&crypt_comp_1.comp); crypt_comp_1.in_flight = (atomic_t)ATOMIC_INIT(0); encrypt_journal(ic, true, commit_start, to_end, &crypt_comp_1); if (try_wait_for_completion(&crypt_comp_1.comp)) { rw_journal(ic, REQ_OP_WRITE, REQ_FUA, commit_start, to_end, &io_comp); - crypt_comp_1.comp = COMPLETION_INITIALIZER_ONSTACK(crypt_comp_1.comp); + reinit_completion(&crypt_comp_1.comp); crypt_comp_1.in_flight = (atomic_t)ATOMIC_INIT(0); encrypt_journal(ic, true, 0, commit_sections - to_end, &crypt_comp_1); wait_for_completion_io(&crypt_comp_1.comp); } else { crypt_comp_2.ic = ic; - crypt_comp_2.comp = COMPLETION_INITIALIZER_ONSTACK(crypt_comp_2.comp); + init_completion(&crypt_comp_2.comp); crypt_comp_2.in_flight = (atomic_t)ATOMIC_INIT(0); encrypt_journal(ic, true, 0, commit_sections - to_end, &crypt_comp_2); wait_for_completion_io(&crypt_comp_1.comp); @@ -1679,7 +1679,7 @@ sleep: dio->in_flight = (atomic_t)ATOMIC_INIT(2); if (need_sync_io) { - read_comp = COMPLETION_INITIALIZER_ONSTACK(read_comp); + init_completion(&read_comp); dio->completion = &read_comp; } else dio->completion = NULL; @@ -1840,7 +1840,7 @@ static void do_journal_write(struct dm_integrity_c *ic, unsigned write_start, comp.ic = ic; comp.in_flight = (atomic_t)ATOMIC_INIT(1); - comp.comp = COMPLETION_INITIALIZER_ONSTACK(comp.comp); + init_completion(&comp.comp); i = write_start; for (n = 0; n < write_sections; n++, i++, wraparound_section(ic, &i)) { @@ -2067,7 +2067,7 @@ static void replay_journal(struct dm_integrity_c *ic) if (ic->journal_io) { struct journal_completion crypt_comp; crypt_comp.ic = ic; - crypt_comp.comp = COMPLETION_INITIALIZER_ONSTACK(crypt_comp.comp); + init_completion(&crypt_comp.comp); crypt_comp.in_flight = (atomic_t)ATOMIC_INIT(0); encrypt_journal(ic, false, 0, ic->journal_sections, &crypt_comp); wait_for_completion(&crypt_comp.comp); @@ -2640,7 +2640,7 @@ static int create_journal(struct dm_integrity_c *ic, char **error) memset(iv, 0x00, ivsize); skcipher_request_set_crypt(req, sg, sg, PAGE_SIZE * ic->journal_pages + sizeof ic->commit_ids, iv); - comp.comp = COMPLETION_INITIALIZER_ONSTACK(comp.comp); + init_completion(&comp.comp); comp.in_flight = (atomic_t)ATOMIC_INIT(1); if (do_crypt(true, req, &comp)) wait_for_completion(&comp.comp); @@ -2697,7 +2697,7 @@ static int create_journal(struct dm_integrity_c *ic, char **error) sg_init_one(&sg, crypt_data, crypt_len); skcipher_request_set_crypt(req, &sg, &sg, crypt_len, iv); - comp.comp = COMPLETION_INITIALIZER_ONSTACK(comp.comp); + init_completion(&comp.comp); comp.in_flight = (atomic_t)ATOMIC_INIT(1); if (do_crypt(true, req, &comp)) wait_for_completion(&comp.comp); -- 2.7.4