blk_set_stacking_limits() is intended to allow stacking drivers to build
up the limits of the stacked device based on the underlying devices'
limits. But in the case of 'max_sectors' the default of
BLK_DEF_MAX_SECTORS (1024) doesn't allow the stacking driver to inherit
a max_sectors larger than 1024.
It is now clear that this artificial limit is getting in the way so
change blk_set_stacking_limits's max_sectors to UINT_MAX (which allows
stacking drivers like dm-multipath to inherit 'max_sectors' from the
underlying paths).
blk_limits_max_hw_sectors() must allow stacking drivers to not have
max_sectors set to BLK_DEF_MAX_SECTORS as a side-effect. Move that
historic constraint to blk_queue_max_hw_sectors().
Reported-by: Vijay Chauhan <vijay.chauhan@xxxxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Cc: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
---
block/blk-settings.c | 8 ++++----
1 files changed, 4 insertions(+), 4 deletions(-)
v2: tweak blk_limits_max_hw_sectors and blk_queue_max_hw_sectors
diff --git a/block/blk-settings.c b/block/blk-settings.c
index d3234fc..b808dfd 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -143,8 +143,7 @@ void blk_set_stacking_limits(struct queue_limits *lim)
lim->discard_zeroes_data = 1;
lim->max_segments = USHRT_MAX;
lim->max_hw_sectors = UINT_MAX;
-
- lim->max_sectors = BLK_DEF_MAX_SECTORS;
+ lim->max_sectors = UINT_MAX;
}
EXPORT_SYMBOL(blk_set_stacking_limits);
@@ -255,8 +254,7 @@ void blk_limits_max_hw_sectors(struct queue_limits *limits, unsigned int max_hw_
}
limits->max_hw_sectors = max_hw_sectors;
- limits->max_sectors = min_t(unsigned int, max_hw_sectors,
- BLK_DEF_MAX_SECTORS);
+ limits->max_sectors = min_not_zero(limits->max_sectors, max_hw_sectors);
}
EXPORT_SYMBOL(blk_limits_max_hw_sectors);
@@ -271,6 +269,8 @@ EXPORT_SYMBOL(blk_limits_max_hw_sectors);
void blk_queue_max_hw_sectors(struct request_queue *q, unsigned int max_hw_sectors)
{
blk_limits_max_hw_sectors(&q->limits, max_hw_sectors);
+ q->limits.max_sectors = min_t(unsigned int, max_hw_sectors,
+ BLK_DEF_MAX_SECTORS);
}
EXPORT_SYMBOL(blk_queue_max_hw_sectors);
--
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