On 24/08/2024 4:49 am, Christoph Hellwig wrote:
We'll start throwing warnings soon when dma_set_seg_boundary and
dma_set_max_seg_size are called on devices for buses that don't fully
support the DMA API. Prepare for that by making the calls in the SCSI
midlayer conditional.
Just thinking ahead, might it be worth a logical "are SG segment limits
relevant?" wrapper around the dev->dma_parms reference? Not a big deal
for now if we think this site is the only user, so either way,
Reviewed-by: Robin Murphy <robin.murphy@xxxxxxx>
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
drivers/scsi/scsi_lib.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 3958a6d14bf457..7f0394c4492033 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1988,8 +1988,15 @@ void scsi_init_limits(struct Scsi_Host *shost, struct queue_limits *lim)
if (shost->no_highmem)
lim->features |= BLK_FEAT_BOUNCE_HIGH;
- dma_set_seg_boundary(dev, shost->dma_boundary);
- dma_set_max_seg_size(dev, shost->max_segment_size);
+ /*
+ * Propagate the DMA formation properties to the dma-mapping layer as
+ * a courtesy service to the LLDDs. This needs to check that the buses
+ * actually support the DMA API first, though.
+ */
+ if (dev->dma_parms) {
+ dma_set_seg_boundary(dev, shost->dma_boundary);
+ dma_set_max_seg_size(dev, shost->max_segment_size);
+ }
}
EXPORT_SYMBOL_GPL(scsi_init_limits);
