scsi: qla2xxx: Use coherent DMA buffer for D_Port diagnostics

qla26xx_dport_diagnostics() streaming-maps the caller's result buffer with
dma_map_single(). The bsg path passes &dd->buf from the __packed struct
qla_dport_diag, where buf lands at a 2-byte offset and shares cachelines
with the surrounding options/unused fields. Mapping such a misaligned
sub-buffer violates the DMA API requirement that streaming buffers be
cacheline aligned and not share a cacheline with other data, and can
corrupt data on non-DMA-coherent architectures.

Allocate a dedicated DMA-coherent buffer inside qla26xx_dport_diagnostics()
for the mailbox command and copy the result back into the caller's buffer.
This removes the streaming map of the misaligned sub-buffer entirely; the
caller's buffer is now only a plain CPU buffer, so its packing no longer
matters.

Fixes: ec89146215d1 ("qla2xxx: Add bsg interface to support D_Port Diagnostics.")
Cc: stable@vger.kernel.org
Reported-by: Sashiko <sashiko-dev@google.com>
Signed-off-by: Nilesh Javali <njavali@marvell.com>
Link: https://patch.msgid.link/20260730155838.2119230-29-njavali@marvell.com
Signed-off-by: Martin K. Petersen (Oracle) <mkp@kernel.org>

0 files changed, 0 insertions, 0 deletions