[SCSI] qla2xxx: Fix for locking issue between driver ISR and mailbox routines

The driver uses ha->mbx_cmd_flags variable to pass information between
its ISR and mailbox routines, however, it does so without the protection of
any locks.  Under certain conditions, this can lead to multiple mailbox
command completions being signaled, which, in turn, leads to a false
mailbox timeout error for the subsequently issued mailbox command.

The issue occurs frequently but intermittenly with the Qlogic 8GFC mezz
card during card initialization, resulting in card initialization failure.

Signed-off-by: Gurinder (Sunny) Shergill <gurinder.shergill@hp.com>
Acked-by: Saurav Kashyap <saurav.kashyap@qlogic.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

5 files changed, 27 insertions, 49 deletions

diff --git a/drivers/scsi/qla2xxx/qla_inline.h b/drivers/scsi/qla2xxx/qla_inline.h
index 98ab921..0a5c895 100644
--- a/drivers/scsi/qla2xxx/qla_inline.h
+++ b/drivers/scsi/qla2xxx/qla_inline.h
@@ -278,3 +278,14 @@ qla2x00_do_host_ramp_up(scsi_qla_host_t *vha)
 
 	set_bit(HOST_RAMP_UP_QUEUE_DEPTH, &vha->dpc_flags);
 }
+
+static inline void
+qla2x00_handle_mbx_completion(struct qla_hw_data *ha, int status)
+{
+	if (test_bit(MBX_INTR_WAIT, &ha->mbx_cmd_flags) &&
+	    (status & MBX_INTERRUPT) && ha->flags.mbox_int) {
+		set_bit(MBX_INTERRUPT, &ha->mbx_cmd_flags);
+		clear_bit(MBX_INTR_WAIT, &ha->mbx_cmd_flags);
+		complete(&ha->mbx_intr_comp);
+	}
+}
diff --git a/drivers/scsi/qla2xxx/qla_isr.c b/drivers/scsi/qla2xxx/qla_isr.c
index 259d920..d2a4c75 100644
--- a/drivers/scsi/qla2xxx/qla_isr.c
+++ b/drivers/scsi/qla2xxx/qla_isr.c
@@ -104,14 +104,9 @@ qla2100_intr_handler(int irq, void *dev_id)
 			RD_REG_WORD(&reg->hccr);
 		}
 	}
+	qla2x00_handle_mbx_completion(ha, status);
 	spin_unlock_irqrestore(&ha->hardware_lock, flags);
 
-	if (test_bit(MBX_INTR_WAIT, &ha->mbx_cmd_flags) &&
-	    (status & MBX_INTERRUPT) && ha->flags.mbox_int) {
-		set_bit(MBX_INTERRUPT, &ha->mbx_cmd_flags);
-		complete(&ha->mbx_intr_comp);
-	}
-
 	return (IRQ_HANDLED);
 }
 
@@ -221,14 +216,9 @@ qla2300_intr_handler(int irq, void *dev_id)
 		WRT_REG_WORD(&reg->hccr, HCCR_CLR_RISC_INT);
 		RD_REG_WORD_RELAXED(&reg->hccr);
 	}
+	qla2x00_handle_mbx_completion(ha, status);
 	spin_unlock_irqrestore(&ha->hardware_lock, flags);
 
-	if (test_bit(MBX_INTR_WAIT, &ha->mbx_cmd_flags) &&
-	    (status & MBX_INTERRUPT) && ha->flags.mbox_int) {
-		set_bit(MBX_INTERRUPT, &ha->mbx_cmd_flags);
-		complete(&ha->mbx_intr_comp);
-	}
-
 	return (IRQ_HANDLED);
 }
 
@@ -2613,14 +2603,9 @@ qla24xx_intr_handler(int irq, void *dev_id)
 		if (unlikely(IS_QLA83XX(ha) && (ha->pdev->revision == 1)))
 			ndelay(3500);
 	}
+	qla2x00_handle_mbx_completion(ha, status);
 	spin_unlock_irqrestore(&ha->hardware_lock, flags);
 
-	if (test_bit(MBX_INTR_WAIT, &ha->mbx_cmd_flags) &&
-	    (status & MBX_INTERRUPT) && ha->flags.mbox_int) {
-		set_bit(MBX_INTERRUPT, &ha->mbx_cmd_flags);
-		complete(&ha->mbx_intr_comp);
-	}
-
 	return IRQ_HANDLED;
 }
 
@@ -2763,13 +2748,9 @@ qla24xx_msix_default(int irq, void *dev_id)
 		}
 		WRT_REG_DWORD(&reg->hccr, HCCRX_CLR_RISC_INT);
 	} while (0);
+	qla2x00_handle_mbx_completion(ha, status);
 	spin_unlock_irqrestore(&ha->hardware_lock, flags);
 
-	if (test_bit(MBX_INTR_WAIT, &ha->mbx_cmd_flags) &&
-	    (status & MBX_INTERRUPT) && ha->flags.mbox_int) {
-		set_bit(MBX_INTERRUPT, &ha->mbx_cmd_flags);
-		complete(&ha->mbx_intr_comp);
-	}
 	return IRQ_HANDLED;
 }
 
diff --git a/drivers/scsi/qla2xxx/qla_mbx.c b/drivers/scsi/qla2xxx/qla_mbx.c
index 9e5d89d..3587ec2 100644
--- a/drivers/scsi/qla2xxx/qla_mbx.c
+++ b/drivers/scsi/qla2xxx/qla_mbx.c
@@ -179,8 +179,6 @@ qla2x00_mailbox_command(scsi_qla_host_t *vha, mbx_cmd_t *mcp)
 
 		wait_for_completion_timeout(&ha->mbx_intr_comp, mcp->tov * HZ);
 
-		clear_bit(MBX_INTR_WAIT, &ha->mbx_cmd_flags);
-
 	} else {
 		ql_dbg(ql_dbg_mbx, vha, 0x1011,
 		    "Cmd=%x Polling Mode.\n", command);
diff --git a/drivers/scsi/qla2xxx/qla_mr.c b/drivers/scsi/qla2xxx/qla_mr.c
index 937fed8..a6df558 100644
--- a/drivers/scsi/qla2xxx/qla_mr.c
+++ b/drivers/scsi/qla2xxx/qla_mr.c
@@ -148,9 +148,6 @@ qlafx00_mailbox_command(scsi_qla_host_t *vha, struct mbx_cmd_32 *mcp)
 		spin_unlock_irqrestore(&ha->hardware_lock, flags);
 
 		wait_for_completion_timeout(&ha->mbx_intr_comp, mcp->tov * HZ);
-
-		clear_bit(MBX_INTR_WAIT, &ha->mbx_cmd_flags);
-
 	} else {
 		ql_dbg(ql_dbg_mbx, vha, 0x112c,
 		    "Cmd=%x Polling Mode.\n", command);
@@ -2934,13 +2931,10 @@ qlafx00_intr_handler(int irq, void *dev_id)
 		QLAFX00_CLR_INTR_REG(ha, clr_intr);
 		QLAFX00_RD_INTR_REG(ha);
 	}
+
+	qla2x00_handle_mbx_completion(ha, status);
 	spin_unlock_irqrestore(&ha->hardware_lock, flags);
 
-	if (test_bit(MBX_INTR_WAIT, &ha->mbx_cmd_flags) &&
-	    (status & MBX_INTERRUPT) && ha->flags.mbox_int) {
-		set_bit(MBX_INTERRUPT, &ha->mbx_cmd_flags);
-		complete(&ha->mbx_intr_comp);
-	}
 	return IRQ_HANDLED;
 }
 
diff --git a/drivers/scsi/qla2xxx/qla_nx.c b/drivers/scsi/qla2xxx/qla_nx.c
index 10754f51..cce0cd0 100644
--- a/drivers/scsi/qla2xxx/qla_nx.c
+++ b/drivers/scsi/qla2xxx/qla_nx.c
@@ -2074,9 +2074,6 @@ qla82xx_intr_handler(int irq, void *dev_id)
 		}
 		WRT_REG_DWORD(&reg->host_int, 0);
 	}
-	spin_unlock_irqrestore(&ha->hardware_lock, flags);
-	if (!ha->flags.msi_enabled)
-		qla82xx_wr_32(ha, ha->nx_legacy_intr.tgt_mask_reg, 0xfbff);
 
 #ifdef QL_DEBUG_LEVEL_17
 	if (!irq && ha->flags.eeh_busy)
@@ -2085,11 +2082,12 @@ qla82xx_intr_handler(int irq, void *dev_id)
 		    status, ha->mbx_cmd_flags, ha->flags.mbox_int, stat);
 #endif
 
-	if (test_bit(MBX_INTR_WAIT, &ha->mbx_cmd_flags) &&
-	    (status & MBX_INTERRUPT) && ha->flags.mbox_int) {
-		set_bit(MBX_INTERRUPT, &ha->mbx_cmd_flags);
-		complete(&ha->mbx_intr_comp);
-	}
+	qla2x00_handle_mbx_completion(ha, status);
+	spin_unlock_irqrestore(&ha->hardware_lock, flags);
+
+	if (!ha->flags.msi_enabled)
+		qla82xx_wr_32(ha, ha->nx_legacy_intr.tgt_mask_reg, 0xfbff);
+
 	return IRQ_HANDLED;
 }
 
@@ -2149,8 +2147,6 @@ qla82xx_msix_default(int irq, void *dev_id)
 		WRT_REG_DWORD(&reg->host_int, 0);
 	} while (0);
 
-	spin_unlock_irqrestore(&ha->hardware_lock, flags);
-
 #ifdef QL_DEBUG_LEVEL_17
 	if (!irq && ha->flags.eeh_busy)
 		ql_log(ql_log_warn, vha, 0x5044,
@@ -2158,11 +2154,9 @@ qla82xx_msix_default(int irq, void *dev_id)
 		    status, ha->mbx_cmd_flags, ha->flags.mbox_int, stat);
 #endif
 
-	if (test_bit(MBX_INTR_WAIT, &ha->mbx_cmd_flags) &&
-		(status & MBX_INTERRUPT) && ha->flags.mbox_int) {
-			set_bit(MBX_INTERRUPT, &ha->mbx_cmd_flags);
-			complete(&ha->mbx_intr_comp);
-	}
+	qla2x00_handle_mbx_completion(ha, status);
+	spin_unlock_irqrestore(&ha->hardware_lock, flags);
+
 	return IRQ_HANDLED;
 }
 
@@ -3345,7 +3339,7 @@ void qla82xx_clear_pending_mbx(scsi_qla_host_t *vha)
 		ha->flags.mbox_busy = 0;
 		ql_log(ql_log_warn, vha, 0x6010,
 		    "Doing premature completion of mbx command.\n");
-		if (test_bit(MBX_INTR_WAIT, &ha->mbx_cmd_flags))
+		if (test_and_clear_bit(MBX_INTR_WAIT, &ha->mbx_cmd_flags))
 			complete(&ha->mbx_intr_comp);
 	}
 }