scsi: libsas: Check link status in ATA prereset()

libata currently attempts to reset even if the SATA disk is unplugged.  To
avoid the meaningless reset of a missing disk, libsas should report offline
status to libata. libata already provides a .prereset callback for this
purpose. This is called by ata_eh_reset() and can be used to influence
whether a reset attempt should be made.

Add sas_ata_preset callback to check status of phy and disk. If the disk is
already offline or phy is disabled, we return -ENOENT to libata to avoid
the reset.

Link: https://lore.kernel.org/r/1595408643-63011-3-git-send-email-luojiaxing@huawei.com
Reviewed-by: John Garry <john.garry@huawei.com>
Reviewed-by: Jason Yan <yanaijie@huawei.com>
Signed-off-by: Luo Jiaxing <luojiaxing@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/libsas/sas_ata.c b/drivers/scsi/libsas/sas_ata.c
index a7d16d2..1b93332 100644 (file)
--- a/drivers/scsi/libsas/sas_ata.c
+++ b/drivers/scsi/libsas/sas_ata.c
@@ -507,8 +507,22 @@ void sas_ata_end_eh(struct ata_port *ap)
        spin_unlock_irqrestore(&ha->lock, flags);
 }
 
+static int sas_ata_prereset(struct ata_link *link, unsigned long deadline)
+{
+       struct ata_port *ap = link->ap;
+       struct domain_device *dev = ap->private_data;
+       struct sas_phy *local_phy = sas_get_local_phy(dev);
+       int res = 0;
+
+       if (!local_phy->enabled || test_bit(SAS_DEV_GONE, &dev->state))
+               res = -ENOENT;
+       sas_put_local_phy(local_phy);
+
+       return res;
+}
+
 static struct ata_port_operations sas_sata_ops = {
-       .prereset               = ata_std_prereset,
+       .prereset               = sas_ata_prereset,
        .hardreset              = sas_ata_hard_reset,
        .error_handler          = ata_std_error_handler,
        .post_internal_cmd      = sas_ata_post_internal,