| Message ID | 20200911215338.44805-3-snitzer@redhat.com (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Delegated to: | Mike Snitzer |
| Headers | show |
| Series | [1/3] block: fix blk_rq_get_max_sectors() to flow more carefully | expand |
On Fri, Sep 11, 2020 at 05:53:37PM -0400, Mike Snitzer wrote: > 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 <snitzer@redhat.com> > --- > 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; > } Looks fine: Reviewed-by: Ming Lei <ming.lei@redhat.com> Thanks, Ming -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel
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; }
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 <snitzer@redhat.com> --- block/blk-settings.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-)