From: Mike Snitzer <snitzer@kernel.org>
To: hch@lst.de
Cc: axboe@kernel.dk, dm-devel@lists.linux.dev,
linux-block@vger.kernel.org, mpatocka@redhat.com,
Abelardo Ricart III <aricart@memnix.com>,
Brandon Smith <freedom@reardencode.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Ming Lei <ming.lei@redhat.com>, Mike Snitzer <snitzer@kernel.org>
Subject: [PATCH for-6.10 1/2] dm-crypt: stop constraining max_segment_size to PAGE_SIZE
Date: Thu, 11 Apr 2024 16:15:28 -0400 [thread overview]
Message-ID: <20240411201529.44846-2-snitzer@kernel.org> (raw)
In-Reply-To: <ZfDeMn6V8WzRUws3@infradead.org>
This change effectively reverts commit 586b286b110e ("dm crypt:
constrain crypt device's max_segment_size to PAGE_SIZE") and relies on
block core's late bio-splitting to ensure that dm-crypt's encryption
bios are split accordingly if they exceed the underlying device's
limits (e.g. max_segment_size).
Commit 586b286b110e was applied as a 4.3 fix for the benefit of
stable@ kernels 4.0+ just after block core's late bio-splitting was
introduced in 4.3 with commit 54efd50bfd873 ("block: make
generic_make_request handle arbitrarily sized bios"). Given block
core's late bio-splitting it is past time that dm-crypt make use of
it.
Also, given the recent need to revert meaningful progress that was
attempted during the 6.9 merge window (see commit bff4b74625fe Revert
"dm: use queue_limits_set") this change allows DM core to safely make
use of queue_limits_set() without risk of breaking dm-crypt on NVMe.
Though it should be noted this commit isn't a prereq for reinstating
DM core's use of queue_limits_set() because blk_validate_limits() was
made less strict with commit b561ea56a264 ("block: allow device to
have both virt_boundary_mask and max segment size").
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
---
drivers/md/dm-crypt.c | 12 ++----------
1 file changed, 2 insertions(+), 10 deletions(-)
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 5bfa35760167..f43a2c0b3d77 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -1656,8 +1656,8 @@ static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone);
/*
* Generate a new unfragmented bio with the given size
- * This should never violate the device limitations (but only because
- * max_segment_size is being constrained to PAGE_SIZE).
+ * This should never violate the device limitations (but if it did then block
+ * core should split the bio as needed).
*
* This function may be called concurrently. If we allocate from the mempool
* concurrently, there is a possibility of deadlock. For example, if we have
@@ -3717,14 +3717,6 @@ static void crypt_io_hints(struct dm_target *ti, struct queue_limits *limits)
{
struct crypt_config *cc = ti->private;
- /*
- * Unfortunate constraint that is required to avoid the potential
- * for exceeding underlying device's max_segments limits -- due to
- * crypt_alloc_buffer() possibly allocating pages for the encryption
- * bio that are not as physically contiguous as the original bio.
- */
- limits->max_segment_size = PAGE_SIZE;
-
limits->logical_block_size =
max_t(unsigned int, limits->logical_block_size, cc->sector_size);
limits->physical_block_size =
--
2.40.0
next prev parent reply other threads:[~2024-04-11 20:15 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <eaeec3b6-75c2-4b65-8c50-2d37450ccdd9@kernel.dk>
[not found] ` <20240311235023.GA1205@cmpxchg.org>
[not found] ` <CAHk-=wgOfw8NBQ2Qyh8QUjhp5z4v--PuciLE7drn5LJkTtgPVw@mail.gmail.com>
[not found] ` <e3fea6c3-7704-46cd-b078-0c6e8d966474@kernel.dk>
[not found] ` <CAHk-=wgXZ6dE1yHK_jQmnSjbEbndyzZHC5dJNsmQYTD2K-m61w@mail.gmail.com>
[not found] ` <Ze-hwnd3ocfJc9xU@redhat.com>
[not found] ` <Ze-rRvKpux44ueao@infradead.org>
2024-03-12 15:22 ` [GIT PULL] Block updates for 6.9-rc1 Mike Snitzer
2024-03-12 16:28 ` Keith Busch
2024-03-12 21:10 ` Christoph Hellwig
2024-03-12 22:22 ` Mike Snitzer
2024-03-12 22:30 ` Christoph Hellwig
2024-03-12 22:50 ` Mike Snitzer
2024-03-12 22:58 ` Christoph Hellwig
2024-04-11 20:15 ` [PATCH for-6.10 0/2] dm: use late bio-splitting and queue_limits_set Mike Snitzer
2024-04-11 20:15 ` Mike Snitzer [this message]
2024-04-12 6:11 ` [PATCH for-6.10 1/2] dm-crypt: stop constraining max_segment_size to PAGE_SIZE Christoph Hellwig
2024-04-15 14:08 ` Mikulas Patocka
2024-04-23 7:32 ` Ming Lei
2024-04-11 20:15 ` [PATCH for-6.10 2/2] dm: use queue_limits_set Mike Snitzer
2024-04-23 7:33 ` Ming Lei
2024-03-13 13:11 ` [GIT PULL] Block updates for 6.9-rc1 Ming Lei
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