essential fix to scsi.c (up to 2.1.100-1)

Dario_Ballabio (Dario_Ballabio@milano.europe.dg.com)
Mon, 4 May 1998 12:37:11 +0200

The enclosed patch to scsi.c, applied on top of 2.1.100-1 changed my
PC (uniprocessor but compiled with SMP=1) with one AHA2940 and one
DPT PM3224W from crashing every few minutes to fully reliable.
Maybe the locking strategy in scsi_bottom_half_handler can be
totally revisited, but the io_rw_lock is definetly required.

-db
%UATTACH
diff -r -u linux-2.1.100-1/drivers/scsi/scsi.c linux/drivers/scsi/scsi.c
--- linux-2.1.100-1/drivers/scsi/scsi.c\011Tue Apr 28 21:58:58 1998
+++ linux/drivers/scsi/scsi.c\011Mon May 4 11:31:36 1998
@@ -1605,6 +1605,7 @@
if( SCpnt == NULL )
return;

+ spin_lock_irqsave(&io_request_lock, flags);
atomic_inc(&recursion_depth);

SCnext = SCpnt->bh_next;
@@ -1696,6 +1697,7 @@
} /* for(; SCpnt...) */

atomic_dec(&recursion_depth);
+ spin_unlock_irqrestore(&io_request_lock, flags);

} /* while(1==1) */

-
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