From: Li Nan <linan122@xxxxxxxxxx>
If a disk is removed and quickly inserted when an I/O error is processing,
the disk may not be able to be re-added. The function call timeline is as
follows:
interrupt scsi_eh
ahci_error_intr
ata_port_freeze
__ata_port_freeze
=>ahci_freeze (turn IRQ off)
ata_port_abort
ata_do_link_abort
ata_port_schedule_eh
=>ata_std_sched_eh
ata_eh_set_pending
set EH_PENDING
scsi_schedule_eh
shost->host_eh_scheduled++ (=1)
scsi_error_handler
=>ata_scsi_error
ata_scsi_port_error_handler
clear EH_PENDING
=>ahci_error_handler
. sata_pmp_error_handler
. ata_eh_reset
. ata_eh_thaw_port
. . =>ahci_thaw (turn IRQ on)
ahci_error_intr . .
ata_port_freeze . .
__ata_port_freeze . .
=>ahci_freeze (turn IRQ off) . .
... . .
ata_eh_set_pending . .
set EH_PENDING . .
scsi_schedule_eh . .
shost->host_eh_scheduled++ (=2) . .
. clear EH_PENDING
check EH_PENDING
=>ata_std_end_eh
host->host_eh_scheduled = 0;
'host_eh_scheduled' is 0 and scsi eh thread will not be scheduled again.
The ata port remains frozen and will never be enabled.
To fix this issue, decrease 'host_eh_scheduled' instead of setting it to 0
so that EH is scheduled again to re-enable the port. Also move the update
of 'nr_active_links' to 0 when 'host_eh_scheduled' is 0 to
ata_scsi_port_error_handler().
Reported-by: luojian <luojian5@xxxxxxxxxx>
Signed-off-by: Li Nan <linan122@xxxxxxxxxx>
---
Changes in v3:
- change patch title, previously it was: "scsi: ata: Fix a race condition
between scsi error handler and ahci interrupt".
- drop the variable 'host' in ata_std_end_eh().
- improve commit message.
drivers/ata/libata-eh.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index 159ba6ba19eb..2d5ecd68b7e0 100644
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -735,6 +735,12 @@ void ata_scsi_port_error_handler(struct Scsi_Host *host, struct ata_port *ap)
*/
ap->ops->end_eh(ap);
+ if (!ap->scsi_host->host_eh_scheduled) {
+ /* make sure nr_active_links is zero after EH */
+ WARN_ON(ap->nr_active_links);
+ ap->nr_active_links = 0;
+ }
+
spin_unlock_irqrestore(ap->lock, flags);
ata_eh_release(ap);
@@ -946,9 +952,7 @@ EXPORT_SYMBOL_GPL(ata_std_sched_eh);
*/
void ata_std_end_eh(struct ata_port *ap)
{
- struct Scsi_Host *host = ap->scsi_host;
-
- host->host_eh_scheduled = 0;
+ ap->scsi_host->host_eh_scheduled--;
}
EXPORT_SYMBOL(ata_std_end_eh);
@@ -3922,10 +3926,6 @@ void ata_eh_finish(struct ata_port *ap)
}
}
}
-
- /* make sure nr_active_links is zero after EH */
- WARN_ON(ap->nr_active_links);
- ap->nr_active_links = 0;
}
/**
--
2.39.2
