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s390/dasd: enforce dma_alignment to ensure proper buffer validation 

The block layer validates buffer alignment using the device's
dma_alignment value. If dma_alignment is smaller than
logical_block_size(bp_block) -1, misaligned buffer incorrectly pass
validation and propagate to the lower-level driver.

This patch adjusts dma_alignment to be at least logical_block_size -1,
ensuring that misalignment buffers are properly rejected at the block
layer and do not reach the DASD driver unnecessarily.

Fixes: 2a07bb64d8 ("s390/dasd: Remove DMA alignment")
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Cc: stable@vger.kernel.org #6.11+
Signed-off-by: Jaehoon Kim <jhkim@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
pull/1354/merge
Jaehoon Kim 2025-09-25 17:47:08 +02:00 committed by Jens Axboe
parent 8f4ed0ce48
commit 130e6de621
1 changed files with 5 additions and 0 deletions
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5
drivers/s390/block/dasd.c
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@ -334,6 +334,11 @@ static int dasd_state_basic_to_ready(struct dasd_device *device)
lim.max_dev_sectors = device->discipline->max_sectors(block);
lim.max_hw_sectors = lim.max_dev_sectors;
lim.logical_block_size = block->bp_block;
/*
* Adjust dma_alignment to match block_size - 1
* to ensure proper buffer alignment checks in the block layer.
*/
lim.dma_alignment = lim.logical_block_size - 1;
if (device->discipline->has_discard) {
unsigned int max_bytes;