[SCSI] qla4xxx: bug fixes

The included patch fixes the following issues:

1. qla3xxx/qla4xxx co-existence issue which can result in a lockup
when qla3xxx driver is unloaded, or when ifdown; ifup is performed on
one of the interfaces correponding to qla3xxx. This is because qla4xxx
HBA supports one ethernet and iscsi interfaces per port. Both iscsi
and ethernet interfaces share the same state machine. The problem has
to do with synchronizing access to the state machine in the event of a
reset

2. mutex_lock() is sometimes not followed by mutex_unlock() prior to
invoking a msleep() in qla4xxx_mailbox_command()

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

1 files changed, 21 insertions, 14 deletions

diff --git a/drivers/scsi/qla4xxx/ql4_mbx.c b/drivers/scsi/qla4xxx/ql4_mbx.c
index b721dc5dd711..7f28657eef3f 100644
--- a/drivers/scsi/qla4xxx/ql4_mbx.c
+++ b/drivers/scsi/qla4xxx/ql4_mbx.c
@@ -29,18 +29,30 @@ int qla4xxx_mailbox_command(struct scsi_qla_host *ha, uint8_t inCount,
         u_long wait_count;
         uint32_t intr_status;
         unsigned long flags = 0;
-        DECLARE_WAITQUEUE(wait, current);
-
-        mutex_lock(&ha->mbox_sem);
-
-        /* Mailbox code active */
-        set_bit(AF_MBOX_COMMAND, &ha->flags);
 
         /* Make sure that pointers are valid */
         if (!mbx_cmd || !mbx_sts) {
                 DEBUG2(printk("scsi%ld: %s: Invalid mbx_cmd or mbx_sts "
                               "pointer\n", ha->host_no, __func__));
-                goto mbox_exit;
+                return status;
+        }
+        /* Mailbox code active */
+        wait_count = MBOX_TOV * 100;
+
+        while (wait_count--) {
+                mutex_lock(&ha->mbox_sem);
+                if (!test_bit(AF_MBOX_COMMAND, &ha->flags)) {
+                        set_bit(AF_MBOX_COMMAND, &ha->flags);
+                        mutex_unlock(&ha->mbox_sem);
+                        break;
+                }
+                mutex_unlock(&ha->mbox_sem);
+                if (!wait_count) {
+                        DEBUG2(printk("scsi%ld: %s: mbox_sem failed\n",
+                                ha->host_no, __func__));
+                        return status;
+                }
+                msleep(10);
         }
 
         /* To prevent overwriting mailbox registers for a command that has
@@ -73,8 +85,6 @@ int qla4xxx_mailbox_command(struct scsi_qla_host *ha, uint8_t inCount,
         spin_unlock_irqrestore(&ha->hardware_lock, flags);
 
         /* Wait for completion */
-        set_current_state(TASK_UNINTERRUPTIBLE);
-        add_wait_queue(&ha->mailbox_wait_queue, &wait);
 
         /*
          * If we don't want status, don't wait for the mailbox command to
@@ -83,8 +93,6 @@ int qla4xxx_mailbox_command(struct scsi_qla_host *ha, uint8_t inCount,
          */
         if (outCount == 0) {
                 status = QLA_SUCCESS;
-                set_current_state(TASK_RUNNING);
-                remove_wait_queue(&ha->mailbox_wait_queue, &wait);
                 goto mbox_exit;
         }
         /* Wait for command to complete */
@@ -108,8 +116,6 @@ int qla4xxx_mailbox_command(struct scsi_qla_host *ha, uint8_t inCount,
                 spin_unlock_irqrestore(&ha->hardware_lock, flags);
                 msleep(10);
         }
-        set_current_state(TASK_RUNNING);
-        remove_wait_queue(&ha->mailbox_wait_queue, &wait);
 
         /* Check for mailbox timeout. */
         if (!test_bit(AF_MBOX_COMMAND_DONE, &ha->flags)) {
@@ -155,9 +161,10 @@ int qla4xxx_mailbox_command(struct scsi_qla_host *ha, uint8_t inCount,
         spin_unlock_irqrestore(&ha->hardware_lock, flags);
 
 mbox_exit:
+        mutex_lock(&ha->mbox_sem);
         clear_bit(AF_MBOX_COMMAND, &ha->flags);
-        clear_bit(AF_MBOX_COMMAND_DONE, &ha->flags);
         mutex_unlock(&ha->mbox_sem);
+        clear_bit(AF_MBOX_COMMAND_DONE, &ha->flags);
 
         return status;
 }