[PATCH] USB: storage: Fix messed-up locking

This is patch as550 from Alan Stern.

Apparently someone changed the SCSI core so that it no longer holds the
host lock when doing a device or bus reset.  usb-storage was updated at
the time, but the change was done carelessly.  Some of the code depends
on that lock being held.

This patch reintroduces the host lock where needed and tries to clarify
the comments explaining why the lock is necessary.  It also moves the
code that clears the TIMED_OUT and ABORTING bitflags so that it executes
as soon as the timed-out command has completed (and while the host lock
is held).

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 8 insertions, 3 deletions

diff --git a/drivers/usb/storage/usb.c b/drivers/usb/storage/usb.c
index cb4c770baf32..f9a9bfa1aef5 100644
--- a/drivers/usb/storage/usb.c
+++ b/drivers/usb/storage/usb.c
@@ -392,11 +392,16 @@ SkipForAbort:
                 /* If an abort request was received we need to signal that
                  * the abort has finished.  The proper test for this is
                  * the TIMED_OUT flag, not srb->result == DID_ABORT, because
-                 * a timeout/abort request might be received after all the
-                 * USB processing was complete. */
-                if (test_bit(US_FLIDX_TIMED_OUT, &us->flags))
+                 * the timeout might have occurred after the command had
+                 * already completed with a different result code. */
+                if (test_bit(US_FLIDX_TIMED_OUT, &us->flags)) {
                         complete(&(us->notify));
 
+                        /* Allow USB transfers to resume */
+                        clear_bit(US_FLIDX_ABORTING, &us->flags);
+                        clear_bit(US_FLIDX_TIMED_OUT, &us->flags);
+                }
+
                 /* finished working on this command */
                 us->srb = NULL;
                 scsi_unlock(host);