From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Snitzer Subject: [PATCH 2/3] block: use lcm_not_zero() when stacking chunk_sectors Date: Fri, 11 Sep 2020 17:53:37 -0400 Message-ID: <20200911215338.44805-3-snitzer@redhat.com> References: <20200911215338.44805-1-snitzer@redhat.com> Return-path: In-Reply-To: <20200911215338.44805-1-snitzer@redhat.com> Sender: linux-block-owner@vger.kernel.org To: Ming Lei Cc: Vijayendra Suman , dm-devel@redhat.com, linux-block@vger.kernel.org List-Id: dm-devel.ids Like 'io_opt', blk_stack_limits() should stack 'chunk_sectors' using lcm_not_zero() rather than min_not_zero() -- otherwise the final 'chunk_sectors' could result in sub-optimal alignment of IO to component devices in the IO stack. Also, if 'chunk_sectors' isn't a multiple of 'physical_block_size' then it is a bug in the driver and the device should be flagged as 'misaligned'. Signed-off-by: Mike Snitzer --- block/blk-settings.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/block/blk-settings.c b/block/blk-settings.c index 76a7e03bcd6c..b09642d5f15e 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -534,6 +534,7 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, t->io_min = max(t->io_min, b->io_min); t->io_opt = lcm_not_zero(t->io_opt, b->io_opt); + t->chunk_sectors = lcm_not_zero(t->chunk_sectors, b->chunk_sectors); /* Physical block size a multiple of the logical block size? */ if (t->physical_block_size & (t->logical_block_size - 1)) { @@ -556,6 +557,13 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, ret = -1; } + /* chunk_sectors a multiple of the physical block size? */ + if (t->chunk_sectors & (t->physical_block_size - 1)) { + t->chunk_sectors = 0; + t->misaligned = 1; + ret = -1; + } + t->raid_partial_stripes_expensive = max(t->raid_partial_stripes_expensive, b->raid_partial_stripes_expensive); @@ -594,10 +602,6 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, t->discard_granularity; } - if (b->chunk_sectors) - t->chunk_sectors = min_not_zero(t->chunk_sectors, - b->chunk_sectors); - t->zoned = max(t->zoned, b->zoned); return ret; } -- 2.15.0