[libata ahci, qstor] fix miscount of scatter/gather entries
Don't directly reference qc->n_elem, as that might cause an off-by-one
error for misaligned (padded) ATAPI transfers.
diff --git a/drivers/scsi/ahci.c b/drivers/scsi/ahci.c
index 57ef7ae..7b0640b 100644
--- a/drivers/scsi/ahci.c
+++ b/drivers/scsi/ahci.c
@@ -474,11 +474,12 @@
ata_tf_from_fis(d2h_fis, tf);
}
-static void ahci_fill_sg(struct ata_queued_cmd *qc)
+static unsigned int ahci_fill_sg(struct ata_queued_cmd *qc)
{
struct ahci_port_priv *pp = qc->ap->private_data;
struct scatterlist *sg;
struct ahci_sg *ahci_sg;
+ unsigned int n_sg = 0;
VPRINTK("ENTER\n");
@@ -493,8 +494,12 @@
ahci_sg->addr = cpu_to_le32(addr & 0xffffffff);
ahci_sg->addr_hi = cpu_to_le32((addr >> 16) >> 16);
ahci_sg->flags_size = cpu_to_le32(sg_len - 1);
+
ahci_sg++;
+ n_sg++;
}
+
+ return n_sg;
}
static void ahci_qc_prep(struct ata_queued_cmd *qc)
@@ -503,13 +508,14 @@
struct ahci_port_priv *pp = ap->private_data;
u32 opts;
const u32 cmd_fis_len = 5; /* five dwords */
+ unsigned int n_elem;
/*
* Fill in command slot information (currently only one slot,
* slot 0, is currently since we don't do queueing)
*/
- opts = (qc->n_elem << 16) | cmd_fis_len;
+ opts = cmd_fis_len;
if (qc->tf.flags & ATA_TFLAG_WRITE)
opts |= AHCI_CMD_WRITE;
if (is_atapi_taskfile(&qc->tf))
@@ -533,7 +539,9 @@
if (!(qc->flags & ATA_QCFLAG_DMAMAP))
return;
- ahci_fill_sg(qc);
+ n_elem = ahci_fill_sg(qc);
+
+ pp->cmd_slot[0].opts |= cpu_to_le32(n_elem << 16);
}
static void ahci_intr_error(struct ata_port *ap, u32 irq_stat)
diff --git a/drivers/scsi/sata_qstor.c b/drivers/scsi/sata_qstor.c
index b2f6324..4a6d306 100644
--- a/drivers/scsi/sata_qstor.c
+++ b/drivers/scsi/sata_qstor.c
@@ -268,7 +268,7 @@
writel(val, (void __iomem *)(ap->ioaddr.scr_addr + (sc_reg * 8)));
}
-static void qs_fill_sg(struct ata_queued_cmd *qc)
+static unsigned int qs_fill_sg(struct ata_queued_cmd *qc)
{
struct scatterlist *sg;
struct ata_port *ap = qc->ap;
@@ -296,6 +296,8 @@
(unsigned long long)addr, len);
nelem++;
}
+
+ return nelem;
}
static void qs_qc_prep(struct ata_queued_cmd *qc)
@@ -304,6 +306,7 @@
u8 dflags = QS_DF_PORD, *buf = pp->pkt;
u8 hflags = QS_HF_DAT | QS_HF_IEN | QS_HF_VLD;
u64 addr;
+ unsigned int nelem;
VPRINTK("ENTER\n");
@@ -313,7 +316,7 @@
return;
}
- qs_fill_sg(qc);
+ nelem = qs_fill_sg(qc);
if ((qc->tf.flags & ATA_TFLAG_WRITE))
hflags |= QS_HF_DIRO;
@@ -324,7 +327,7 @@
buf[ 0] = QS_HCB_HDR;
buf[ 1] = hflags;
*(__le32 *)(&buf[ 4]) = cpu_to_le32(qc->nsect * ATA_SECT_SIZE);
- *(__le32 *)(&buf[ 8]) = cpu_to_le32(qc->n_elem);
+ *(__le32 *)(&buf[ 8]) = cpu_to_le32(nelem);
addr = ((u64)pp->pkt_dma) + QS_CPB_BYTES;
*(__le64 *)(&buf[16]) = cpu_to_le64(addr);