[SCSI] aacraid: Re-start helper thread if it dies

Received from Mark Salyzyn

Since the helper thread for the driver can be killed unceremoniously by
an application, we detect the loss of the helper and restart it.

Signed-off-by: Mark Haverkamp <markh@osdl.org>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/drivers/scsi/aacraid/commctrl.c b/drivers/scsi/aacraid/commctrl.c
index 47fefca72695..9f75144e5247 100644
--- a/drivers/scsi/aacraid/commctrl.c
+++ b/drivers/scsi/aacraid/commctrl.c
@@ -38,6 +38,8 @@
 #include <linux/completion.h>
 #include <linux/dma-mapping.h>
 #include <linux/blkdev.h>
+#include <linux/delay.h>
+#include <linux/kthread.h>
 #include <asm/semaphore.h>
 #include <asm/uaccess.h>
 
@@ -293,6 +295,16 @@ return_fib:
                 status = 0;
         } else {
                 spin_unlock_irqrestore(&dev->fib_lock, flags);
+                /* If someone killed the AIF aacraid thread, restart it */
+                status = !dev->aif_thread;
+                if (status && dev->queues && dev->fsa_dev) {
+                        /* Be paranoid, be very paranoid! */
+                        kthread_stop(dev->thread);
+                        ssleep(1);
+                        dev->aif_thread = 0;
+                        dev->thread = kthread_run(aac_command_thread, dev, dev->name);
+                        ssleep(1);
+                }
                 if (f.wait) {
                         if(down_interruptible(&fibctx->wait_sem) < 0) {
                                 status = -EINTR;