01_libata_add-ata_poll_qc_complete.patch
Previously, libata polling functions turned irq back on and
completed qc commands without holding host lock. This creates
a race condition between the polling task and interrupts from
other ports on the same host set or spurious interrupt from
itself.
This patch implements ata_poll_qc_complete which enables irq
and completes qc atomically and convert all polling functions.
Note: Unlike other functions, atapi_packet_task() didn't use
to turn irq back on on error exits. This patch makes it use
ata_poll_qc_complete, so irq is now turned back on on error
exits.
Note: With this change, ALL invocations of ata_qc_complete()
are now done under host_set lock.
Signed-off-by: Tejun Heo <[EMAIL PROTECTED]>
libata-core.c | 32 ++++++++++++++++++++++----------
1 files changed, 22 insertions(+), 10 deletions(-)
Index: work/drivers/scsi/libata-core.c
===================================================================
--- work.orig/drivers/scsi/libata-core.c 2005-08-20 23:13:40.000000000
+0900
+++ work/drivers/scsi/libata-core.c 2005-08-20 23:13:40.000000000 +0900
@@ -2402,6 +2402,24 @@ static int ata_sg_setup(struct ata_queue
}
/**
+ * ata_poll_qc_complete - turn irq back on and finish qc
+ * @qc: Command to complete
+ * @drv_stat: ATA status register content
+ *
+ * LOCKING:
+ * None. (grabs host lock)
+ */
+void ata_poll_qc_complete(struct ata_queued_cmd *qc, u8 drv_stat)
+{
+ struct ata_port *ap = qc->ap;
+
+ spin_lock_irq(&ap->host_set->lock);
+ ata_irq_on(ap);
+ ata_qc_complete(qc, drv_stat);
+ spin_unlock_irq(&ap->host_set->lock);
+}
+
+/**
* ata_pio_poll -
* @ap:
*
@@ -2492,9 +2510,7 @@ static void ata_pio_complete (struct ata
ap->pio_task_state = PIO_ST_IDLE;
- ata_irq_on(ap);
-
- ata_qc_complete(qc, drv_stat);
+ ata_poll_qc_complete(qc, drv_stat);
}
@@ -2717,9 +2733,7 @@ static void ata_pio_block(struct ata_por
if ((status & ATA_DRQ) == 0) {
ap->pio_task_state = PIO_ST_IDLE;
- ata_irq_on(ap);
-
- ata_qc_complete(qc, status);
+ ata_poll_qc_complete(qc, status);
return;
}
@@ -2749,9 +2763,7 @@ static void ata_pio_error(struct ata_por
ap->pio_task_state = PIO_ST_IDLE;
- ata_irq_on(ap);
-
- ata_qc_complete(qc, drv_stat | ATA_ERR);
+ ata_poll_qc_complete(qc, drv_stat | ATA_ERR);
}
static void ata_pio_task(void *_data)
@@ -3656,7 +3668,7 @@ static void atapi_packet_task(void *_dat
return;
err_out:
- ata_qc_complete(qc, ATA_ERR);
+ ata_poll_qc_complete(qc, ATA_ERR);
}
-
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