Interrupts from devices sharing the same IRQ could cause
ata_host_intr to finish commands being processed by atapi_packet_task
if the commands are using ATA_PROT_ATAPI_NODATA or ATA_PROT_ATAPI_DMA
protocol. This is because libata interrupt handler is unaware that
interrupts are not expected during that period. This patch adds
ATA_FLAG_NOINTR flag to tell the interrupt handler that we're not
expecting interrupts.
Note that once proper HSM is implemented for interrupt-driven PIO,
this should be merged into it and this flag will be removed.
Signed-off-by: Tejun Heo <[EMAIL PROTECTED]>
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -3218,11 +3218,13 @@ int ata_qc_issue_prot(struct ata_queued_
break;
case ATA_PROT_ATAPI_NODATA:
+ ap->flags |= ATA_FLAG_NOINTR;
ata_tf_to_host_nolock(ap, &qc->tf);
queue_work(ata_wq, &ap->packet_task);
break;
case ATA_PROT_ATAPI_DMA:
+ ap->flags |= ATA_FLAG_NOINTR;
ap->ops->tf_load(ap, &qc->tf); /* load tf registers */
ap->ops->bmdma_setup(qc); /* set up bmdma */
queue_work(ata_wq, &ap->packet_task);
@@ -3576,7 +3578,8 @@ irqreturn_t ata_interrupt (int irq, void
struct ata_port *ap;
ap = host_set->ports[i];
- if (ap && (!(ap->flags & ATA_FLAG_PORT_DISABLED))) {
+ if (ap &&
+ !(ap->flags & (ATA_FLAG_PORT_DISABLED | ATA_FLAG_NOINTR))) {
struct ata_queued_cmd *qc;
qc = ata_qc_from_tag(ap, ap->active_tag);
@@ -3628,19 +3631,25 @@ static void atapi_packet_task(void *_dat
/* send SCSI cdb */
DPRINTK("send cdb\n");
assert(ap->cdb_len >= 12);
- ata_data_xfer(ap, qc->cdb, ap->cdb_len, 1);
- /* if we are DMA'ing, irq handler takes over from here */
- if (qc->tf.protocol == ATA_PROT_ATAPI_DMA)
- ap->ops->bmdma_start(qc); /* initiate bmdma */
-
- /* non-data commands are also handled via irq */
- else if (qc->tf.protocol == ATA_PROT_ATAPI_NODATA) {
- /* do nothing */
- }
+ if (qc->tf.protocol == ATA_PROT_ATAPI_DMA ||
+ qc->tf.protocol == ATA_PROT_ATAPI_NODATA) {
+ /* Once we're done issuing command and kicking bmdma,
+ * irq handler takes over. To not lose irq, we need
+ * to clear NOINTR flag before sending cdb, but
+ * interrupt handler shouldn't be invoked before we're
+ * finished. Hence, the following locking.
+ */
+ spin_lock_irq(&ap->host_set->lock);
+ ap->flags &= ~ATA_FLAG_NOINTR;
+ ata_data_xfer(ap, qc->cdb, ap->cdb_len, 1);
+ if (qc->tf.protocol == ATA_PROT_ATAPI_DMA)
+ ap->ops->bmdma_start(qc); /* initiate bmdma */
+ spin_unlock_irq(&ap->host_set->lock);
+ } else {
+ ata_data_xfer(ap, qc->cdb, ap->cdb_len, 1);
- /* PIO commands are handled by polling */
- else {
+ /* PIO commands are handled by polling */
ap->pio_task_state = PIO_ST;
queue_work(ata_wq, &ap->pio_task);
}
diff --git a/include/linux/libata.h b/include/linux/libata.h
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -113,6 +113,8 @@ enum {
ATA_FLAG_MMIO = (1 << 6), /* use MMIO, not PIO */
ATA_FLAG_SATA_RESET = (1 << 7), /* use COMRESET */
ATA_FLAG_PIO_DMA = (1 << 8), /* PIO cmds via DMA */
+ ATA_FLAG_NOINTR = (1 << 9), /* FIXME: Remove this once
+ * proper HSM is in place. */
ATA_QCFLAG_ACTIVE = (1 << 1), /* cmd not yet ack'd to scsi lyer */
ATA_QCFLAG_SG = (1 << 3), /* have s/g table? */
-
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