ahci: pp->active_link is not reliable when FBS is enabled

pp->active_link is not reliable when FBS is enabled.
Both PORT_SCR_ACT and PORT_CMD_ISSUE should be checked
because mixed NCQ and non-NCQ commands may be in flight.

Signed-off-by: Shane Huang <shane.huang@amd.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 17 insertions, 6 deletions

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index e7e2c7a147f1..fdc9bcbe55a2 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -2278,7 +2278,7 @@ static void ahci_port_intr(struct ata_port *ap)
         struct ahci_port_priv *pp = ap->private_data;
         struct ahci_host_priv *hpriv = ap->host->private_data;
         int resetting = !!(ap->pflags & ATA_PFLAG_RESETTING);
-        u32 status, qc_active;
+        u32 status, qc_active = 0;
         int rc;
 
         status = readl(port_mmio + PORT_IRQ_STAT);
@@ -2336,11 +2336,22 @@ static void ahci_port_intr(struct ata_port *ap)
                 }
         }
 
-        /* pp->active_link is valid iff any command is in flight */
-        if (ap->qc_active && pp->active_link->sactive)
-                qc_active = readl(port_mmio + PORT_SCR_ACT);
-        else
-                qc_active = readl(port_mmio + PORT_CMD_ISSUE);
+        /* pp->active_link is not reliable once FBS is enabled, both
+         * PORT_SCR_ACT and PORT_CMD_ISSUE should be checked because
+         * NCQ and non-NCQ commands may be in flight at the same time.
+         */
+        if (pp->fbs_enabled) {
+                if (ap->qc_active) {
+                        qc_active = readl(port_mmio + PORT_SCR_ACT);
+                        qc_active |= readl(port_mmio + PORT_CMD_ISSUE);
+                }
+        } else {
+                /* pp->active_link is valid iff any command is in flight */
+                if (ap->qc_active && pp->active_link->sactive)
+                        qc_active = readl(port_mmio + PORT_SCR_ACT);
+                else
+                        qc_active = readl(port_mmio + PORT_CMD_ISSUE);
+        }
 
         rc = ata_qc_complete_multiple(ap, qc_active);