From: Jaehoon Kim Date: Thu, 25 Sep 2025 15:47:08 +0000 (+0200) Subject: s390/dasd: enforce dma_alignment to ensure proper buffer validation X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=130e6de62107116eba124647116276266be0f84c;p=thirdparty%2Fkernel%2Fstable.git 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: 2a07bb64d801 ("s390/dasd: Remove DMA alignment") Reviewed-by: Stefan Haberland Cc: stable@vger.kernel.org #6.11+ Signed-off-by: Jaehoon Kim Signed-off-by: Stefan Haberland Signed-off-by: Jens Axboe --- diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c index 1d624388075ff..7765e40f7ceac 100644 --- a/drivers/s390/block/dasd.c +++ b/drivers/s390/block/dasd.c @@ -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;