ncr5380: Fix autosense bugs

NCR5380_information_transfer() may re-queue a command for autosense,
after calling scsi_eh_prep_cmnd(). This creates several possibilities:

1. Reselection may intervene before the re-queued command gets processed.
   If the reconnected command then undergoes autosense, this causes the
   scsi_eh_save data from the previous command to be overwritten.

2. After NCR5380_information_transfer() calls scsi_eh_prep_cmnd(),
   a new REQUEST SENSE command may arrive. This would be queued ahead
   of any command already undergoing autosense, which means the
   scsi_eh_save data might be restored to the wrong command.

3. After NCR5380_information_transfer() calls scsi_eh_prep_cmnd(),
   eh_abort_handler() may abort the command. But the scsi_eh_save data is
   not discarded, which means the scsi_eh_save data might be incorrectly
   restored to the next REQUEST SENSE command issued.

This patch adds a new autosense list so that commands that are re-queued
because of a CHECK CONDITION result can be kept apart from the REQUEST
SENSE commands that arrive via queuecommand.

This patch also adds a function dedicated to dequeueing and preparing the
next command for processing. By refactoring the main loop in this way,
scsi_eh_save takes place when an autosense command is dequeued rather
than when re-queued.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Tested-by: Ondrej Zary <linux@rainbow-software.org>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/scsi/NCR5380.h b/drivers/scsi/NCR5380.h
index 56252a5516d7..81e077afa8db 100644
--- a/drivers/scsi/NCR5380.h
+++ b/drivers/scsi/NCR5380.h
@@ -256,10 +256,12 @@ struct NCR5380_hostdata {
 	unsigned char last_message;		/* last message OUT */
 	struct scsi_cmnd *connected;		/* currently connected cmnd */
 	struct list_head unissued;		/* waiting to be issued */
+	struct list_head autosense;		/* priority issue queue */
 	struct list_head disconnected;		/* waiting for reconnect */
 	spinlock_t lock;			/* protects this struct */
 	int flags;
 	struct scsi_eh_save ses;
+	struct scsi_cmnd *sensing;
 	char info[256];
 	int read_overruns;                /* number of bytes to cut from a
 	                                   * transfer to handle chip overruns */