On Wed, Jun 29, 2022 at 3:16 AM Michael Schmitz <schmitzmic@xxxxxxxxx> wrote:
Use dma_map_single() for a2091 driver (leave bounce buffer
logic unchanged).
Use dma_set_mask_and_coherent() to avoid explicit cache
flushes.
Compile-tested only.
CC: linux-scsi@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/r/6d1d88ee-1cf6-c735-1e6d-bafd2096e322@xxxxxxxxx
Signed-off-by: Michael Schmitz <schmitzmic@xxxxxxxxx>
Reviewed-by: Arnd Bergmann <arnd@xxxxxxxx>
+
+ addr = dma_map_single(hdata->dev, scsi_pointer->ptr,
+ len, DMA_DIR(dir_in));
+ if (dma_mapping_error(hdata->dev, addr)) {
+ dev_warn(hdata->dev, "cannot map SCSI data block %p\n",
+ scsi_pointer->ptr);
+ return 1;
+ }
+ scsi_pointer->dma_handle = addr;
/* don't allow DMA if the physical address is bad */
if (addr & A2091_XFER_MASK) {
+ /* drop useless mapping */
+ dma_unmap_single(hdata->dev, scsi_pointer->dma_handle,
+ scsi_pointer->this_residual,
+ DMA_DIR(dir_in));
I think you could save the extra map/unmap here if you wanted, but that
would risk introducing bugs since it requires a larger rework.
+ scsi_pointer->dma_handle = (dma_addr_t) NULL;
+
wh->dma_bounce_len = (scsi_pointer->this_residual + 511) & ~0x1ff;
wh->dma_bounce_buffer = kmalloc(wh->dma_bounce_len,
GFP_KERNEL);
Not your bug, but if there is memory above the A2091_XFER_MASK limit,
this would need to use GFP_DMA instead of GFP_KERNEL.
Arnd
