[PATCH] ide: Fix crash on repeated reset

Michal Miroslaw reported a problem (bugzilla #7023) where a user initiated
reset while the IDE layer was already resetting the channel caused a crash,
and provided a rough fix.

This is a slightly cleaner version of the fix which tracks the reset state
and blocks further reset requests while a reset is in progress.

Note this is not a security issue - random end users can't access the
ioctl in question anyway.

Signed-off-by: Alan Cox <alan@redhat.com>
Cc: Michal Miroslaw <mirq-linux@rere.qmqm.pl>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/ide/ide-iops.c b/drivers/ide/ide-iops.c
index 77703ac..badde63 100644
--- a/drivers/ide/ide-iops.c
+++ b/drivers/ide/ide-iops.c
@@ -998,6 +998,7 @@
 	}
 	/* done polling */
 	hwgroup->polling = 0;
+	hwgroup->resetting = 0;
 	return ide_stopped;
 }
 
@@ -1057,6 +1058,7 @@
 		}
 	}
 	hwgroup->polling = 0;	/* done polling */
+	hwgroup->resetting = 0; /* done reset attempt */
 	return ide_stopped;
 }
 
@@ -1143,6 +1145,7 @@
 
 	/* For an ATAPI device, first try an ATAPI SRST. */
 	if (drive->media != ide_disk && !do_not_try_atapi) {
+		hwgroup->resetting = 1;
 		pre_reset(drive);
 		SELECT_DRIVE(drive);
 		udelay (20);
@@ -1168,6 +1171,7 @@
 		return ide_stopped;
 	}
 
+	hwgroup->resetting = 1;
 	/*
 	 * Note that we also set nIEN while resetting the device,
 	 * to mask unwanted interrupts from the interface during the reset.