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-rw-r--r--drivers/ata/libata-core.c33
1 files changed, 10 insertions, 23 deletions
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 642097a7d60..094b51891db 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -4109,6 +4109,7 @@ static void ata_fill_sg(struct ata_queued_cmd *qc)
if (idx)
ap->prd[idx - 1].flags_len |= cpu_to_le32(ATA_PRD_EOT);
}
+
/**
* ata_check_atapi_dma - Check whether ATAPI DMA can be supported
* @qc: Metadata associated with taskfile to check
@@ -4126,33 +4127,19 @@ static void ata_fill_sg(struct ata_queued_cmd *qc)
int ata_check_atapi_dma(struct ata_queued_cmd *qc)
{
struct ata_port *ap = qc->ap;
- int rc = 0; /* Assume ATAPI DMA is OK by default */
-
- /* some drives can only do ATAPI DMA on read/write */
- if (unlikely(qc->dev->horkage & ATA_HORKAGE_DMA_RW_ONLY)) {
- struct scsi_cmnd *cmd = qc->scsicmd;
- u8 *scsicmd = cmd->cmnd;
-
- switch (scsicmd[0]) {
- case READ_10:
- case WRITE_10:
- case READ_12:
- case WRITE_12:
- case READ_6:
- case WRITE_6:
- /* atapi dma maybe ok */
- break;
- default:
- /* turn off atapi dma */
- return 1;
- }
- }
+
+ /* Don't allow DMA if it isn't multiple of 16 bytes. Quite a
+ * few ATAPI devices choke on such DMA requests.
+ */
+ if (unlikely(qc->nbytes & 15))
+ return 1;
if (ap->ops->check_atapi_dma)
- rc = ap->ops->check_atapi_dma(qc);
+ return ap->ops->check_atapi_dma(qc);
- return rc;
+ return 0;
}
+
/**
* ata_qc_prep - Prepare taskfile for submission
* @qc: Metadata associated with taskfile to be prepared