[SCSI] aic79xx bus reset update

As James B. correctly noted, ahd_reset_channel() in
ahd_linux_bus_reset() should be protected by ahd_lock().  However, the
main reason for not doing so was a deadlock with the interesting
polling mechanism to detect the end a bus reset.

This patch replaces the polling mechanism with a saner signalling via
flags; it also gives us the benefit of detecting any multiple calls to
ahd_reset_channel().

Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/scsi/aic7xxx/aic79xx_osm.c b/drivers/scsi/aic7xxx/aic79xx_osm.c
index bcced0a417e6..66e4a47bb9ee 100644
--- a/drivers/scsi/aic7xxx/aic79xx_osm.c
+++ b/drivers/scsi/aic7xxx/aic79xx_osm.c
@@ -782,6 +782,7 @@ ahd_linux_bus_reset(struct scsi_cmnd *cmd)
 {
         struct ahd_softc *ahd;
         int    found;
+        unsigned long flags;
 
         ahd = *(struct ahd_softc **)cmd->device->host->hostdata;
 #ifdef AHD_DEBUG
@@ -789,8 +790,11 @@ ahd_linux_bus_reset(struct scsi_cmnd *cmd)
                 printf("%s: Bus reset called for cmd %p\n",
                        ahd_name(ahd), cmd);
 #endif
+        ahd_lock(ahd, &flags);
+
         found = ahd_reset_channel(ahd, scmd_channel(cmd) + 'A',
                                   /*initiate reset*/TRUE);
+        ahd_unlock(ahd, &flags);
 
         if (bootverbose)
                 printf("%s: SCSI bus reset delivered. "