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* [PATCH v4] ata: libata-eh: Honor all EH scheduling requests
@ 2023-09-06  8:42 linan666
  2023-09-07  7:43 ` kernel test robot
  0 siblings, 1 reply; 7+ messages in thread
From: linan666 @ 2023-09-06  8:42 UTC (permalink / raw)
  To: dlemoal, htejun
  Cc: linux-ide, linux-kernel, linan122, yukuai3, yi.zhang, houtao1,
	yangerkun

From: Li Nan <linan122@huawei.com>

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().

Cc: stable@vger.kernel.org
Fixes: ad9e27624479 ("[PATCH] libata-eh-fw: update ata_scsi_error() for new EH")
Reported-by: luojian <luojian5@huawei.com>
Signed-off-by: Li Nan <linan122@huawei.com>
Reviewed-by: Niklas Cassel <niklas.cassel@wdc.com>
---
Changes in v4:
 - add fix tag and Cc stable

 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


^ permalink raw reply related	[flat|nested] 7+ messages in thread
end of thread, other threads:[~2023-09-11 22:11 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2023-09-06  8:42 [PATCH v4] ata: libata-eh: Honor all EH scheduling requests linan666
2023-09-07  7:43 ` kernel test robot
2023-09-07 21:02   ` Niklas Cassel
2023-09-11  7:16     ` Damien Le Moal
2023-09-11 11:32       ` Li Nan
2023-09-11 12:40       ` Niklas Cassel
2023-09-11 11:26     ` Li Nan

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