3 files changed, 82 insertions, 0 deletions

diff --git a/include/scsi/scsi.h b/include/scsi/scsi.h
index 32742c4563de..2b5b9356c314 100644
--- a/include/scsi/scsi.h
+++ b/include/scsi/scsi.h
@@ -400,6 +400,7 @@ struct scsi_lun {
 #define SOFT_ERROR      0x2005
 #define ADD_TO_MLQUEUE  0x2006
 #define TIMEOUT_ERROR   0x2007
+#define SCSI_RETURN_NOT_HANDLED   0x2008
 
 /*
  * Midlevel queue return values.
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index f6a9fe0ef09c..06b979f105b7 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -161,9 +161,29 @@ struct scsi_device {
 
         struct execute_work     ew; /* used to get process context on put */
 
+        struct scsi_dh_data     *scsi_dh_data;
         enum scsi_device_state sdev_state;
         unsigned long           sdev_data[0];
 } __attribute__((aligned(sizeof(unsigned long))));
+
+struct scsi_device_handler {
+        /* Used by the infrastructure */
+        struct list_head list; /* list of scsi_device_handlers */
+        struct notifier_block nb;
+
+        /* Filled by the hardware handler */
+        struct module *module;
+        const char *name;
+        int (*check_sense)(struct scsi_device *, struct scsi_sense_hdr *);
+        int (*activate)(struct scsi_device *);
+        int (*prep_fn)(struct scsi_device *, struct request *);
+};
+
+struct scsi_dh_data {
+        struct scsi_device_handler *scsi_dh;
+        char buf[0];
+};
+
 #define to_scsi_device(d)       \
         container_of(d, struct scsi_device, sdev_gendev)
 #define class_to_sdev(d)        \
@@ -230,7 +250,9 @@ extern struct scsi_device *__scsi_add_device(struct Scsi_Host *,
                 uint, uint, uint, void *hostdata);
 extern int scsi_add_device(struct Scsi_Host *host, uint channel,
                            uint target, uint lun);
+extern int scsi_register_device_handler(struct scsi_device_handler *scsi_dh);
 extern void scsi_remove_device(struct scsi_device *);
+extern int scsi_unregister_device_handler(struct scsi_device_handler *scsi_dh);
 
 extern int scsi_device_get(struct scsi_device *);
 extern void scsi_device_put(struct scsi_device *);
diff --git a/include/scsi/scsi_dh.h b/include/scsi/scsi_dh.h
new file mode 100644
index 000000000000..04d0d8495c83
--- /dev/null
+++ b/include/scsi/scsi_dh.h
@@ -0,0 +1,59 @@
+/*
+ * Header file for SCSI device handler infrastruture.
+ *
+ * Modified version of patches posted by Mike Christie <michaelc@cs.wisc.edu>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Copyright IBM Corporation, 2007
+ *      Authors:
+ *               Chandra Seetharaman <sekharan@us.ibm.com>
+ *               Mike Anderson <andmike@linux.vnet.ibm.com>
+ */
+
+#include <scsi/scsi_device.h>
+
+enum {
+        SCSI_DH_OK = 0,
+        /*
+         * device errors
+         */
+        SCSI_DH_DEV_FAILED,     /* generic device error */
+        SCSI_DH_DEV_TEMP_BUSY,
+        SCSI_DH_DEVICE_MAX,     /* max device blkerr definition */
+
+        /*
+         * transport errors
+         */
+        SCSI_DH_NOTCONN = SCSI_DH_DEVICE_MAX + 1,
+        SCSI_DH_CONN_FAILURE,
+        SCSI_DH_TRANSPORT_MAX,  /* max transport blkerr definition */
+
+        /*
+         * driver and generic errors
+         */
+        SCSI_DH_IO = SCSI_DH_TRANSPORT_MAX + 1, /* generic error */
+        SCSI_DH_INVALID_IO,
+        SCSI_DH_RETRY,          /* retry the req, but not immediately */
+        SCSI_DH_IMM_RETRY,      /* immediately retry the req */
+        SCSI_DH_TIMED_OUT,
+        SCSI_DH_RES_TEMP_UNAVAIL,
+        SCSI_DH_DEV_OFFLINED,
+        SCSI_DH_NOSYS,
+        SCSI_DH_DRIVER_MAX,
+};
+
+extern int scsi_dh_activate(struct request_queue *);
+extern int scsi_dh_handler_exist(const char *);