scsi: revert "[SCSI] Get rid of scsi_cmnd->done"

This reverts commit 6f5391c283d7fdcf24bf40786ea79061919d1e1d ("[SCSI]
Get rid of scsi_cmnd->done") that was supposed to be a cleanup commit,
but apparently it causes regressions:

  Bug 9370 - v2.6.24-rc2-409-g9418d5d: attempt to access beyond end of device
  http://bugzilla.kernel.org/show_bug.cgi?id=9370

this patch should be reintroduced in a more split-up form to make
testing of it easier.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Matthew Wilcox <matthew@wil.cx>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

9 files changed, 58 insertions, 43 deletions

diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index 0fb1709ce5e..7ceb8209e5d 100644
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -59,7 +59,6 @@
 #include <scsi/scsi_cmnd.h>
 #include <scsi/scsi_dbg.h>
 #include <scsi/scsi_device.h>
-#include <scsi/scsi_driver.h>
 #include <scsi/scsi_eh.h>
 #include <scsi/scsi_host.h>
 #include <scsi/scsi_tcq.h>
@@ -368,8 +367,9 @@ void scsi_log_send(struct scsi_cmnd *cmd)
                         scsi_print_command(cmd);
                         if (level > 3) {
                                 printk(KERN_INFO "buffer = 0x%p, bufflen = %d,"
-                                       " queuecommand 0x%p\n",
+                                       " done = 0x%p, queuecommand 0x%p\n",
                                         scsi_sglist(cmd), scsi_bufflen(cmd),
+                                        cmd->done,
                                         cmd->device->host->hostt->queuecommand);
 
                         }
@@ -654,12 +654,6 @@ void __scsi_done(struct scsi_cmnd *cmd)
         blk_complete_request(rq);
 }
 
-/* Move this to a header if it becomes more generally useful */
-static struct scsi_driver *scsi_cmd_to_driver(struct scsi_cmnd *cmd)
-{
-        return *(struct scsi_driver **)cmd->request->rq_disk->private_data;
-}
-
 /*
  * Function:    scsi_finish_command
  *
@@ -671,8 +665,6 @@ void scsi_finish_command(struct scsi_cmnd *cmd)
 {
         struct scsi_device *sdev = cmd->device;
         struct Scsi_Host *shost = sdev->host;
-        struct scsi_driver *drv;
-        unsigned int good_bytes;
 
         scsi_device_unbusy(sdev);
 
@@ -698,13 +690,7 @@ void scsi_finish_command(struct scsi_cmnd *cmd)
                                 "Notifying upper driver of completion "
                                 "(result %x)\n", cmd->result));
 
-        good_bytes = cmd->request_bufflen;
-        if (cmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {
-                drv = scsi_cmd_to_driver(cmd);
-                if (drv->done)
-                        good_bytes = drv->done(cmd);
-        }
-        scsi_io_completion(cmd, good_bytes);
+        cmd->done(cmd);
 }
 EXPORT_SYMBOL(scsi_finish_command);
 
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index ebaca4ca4a1..70700b97c91 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -1699,6 +1699,7 @@ scsi_reset_provider(struct scsi_device *dev, int flag)
         memset(&scmd->cmnd, '\0', sizeof(scmd->cmnd));
     
         scmd->scsi_done         = scsi_reset_provider_done_command;
+        scmd->done                      = NULL;
         scmd->request_buffer            = NULL;
         scmd->request_bufflen           = 0;
 
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 0e81e4cf887..8df8267ce31 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1092,6 +1092,7 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
         }
         scsi_end_request(cmd, 0, this_count, !result);
 }
+EXPORT_SYMBOL(scsi_io_completion);
 
 /*
  * Function:    scsi_init_io()
@@ -1170,6 +1171,18 @@ static struct scsi_cmnd *scsi_get_cmd_from_req(struct scsi_device *sdev,
         return cmd;
 }
 
+static void scsi_blk_pc_done(struct scsi_cmnd *cmd)
+{
+        BUG_ON(!blk_pc_request(cmd->request));
+        /*
+         * This will complete the whole command with uptodate=1 so
+         * as far as the block layer is concerned the command completed
+         * successfully. Since this is a REQ_BLOCK_PC command the
+         * caller should check the request's errors value
+         */
+        scsi_io_completion(cmd, cmd->request_bufflen);
+}
+
 int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
 {
         struct scsi_cmnd *cmd;
@@ -1219,6 +1232,7 @@ int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
         cmd->transfersize = req->data_len;
         cmd->allowed = req->retries;
         cmd->timeout_per_command = req->timeout;
+        cmd->done = scsi_blk_pc_done;
         return BLKPREP_OK;
 }
 EXPORT_SYMBOL(scsi_setup_blk_pc_cmnd);
diff --git a/drivers/scsi/scsi_priv.h b/drivers/scsi/scsi_priv.h
index eff00595189..ee8efe849bf 100644
--- a/drivers/scsi/scsi_priv.h
+++ b/drivers/scsi/scsi_priv.h
@@ -68,7 +68,6 @@ extern int scsi_maybe_unblock_host(struct scsi_device *sdev);
 extern void scsi_device_unbusy(struct scsi_device *sdev);
 extern int scsi_queue_insert(struct scsi_cmnd *cmd, int reason);
 extern void scsi_next_command(struct scsi_cmnd *cmd);
-extern void scsi_io_completion(struct scsi_cmnd *, unsigned int);
 extern void scsi_run_host_queues(struct Scsi_Host *shost);
 extern struct request_queue *scsi_alloc_queue(struct scsi_device *sdev);
 extern void scsi_free_queue(struct request_queue *q);
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index a69b155f39a..cb85296d538 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -86,19 +86,6 @@ MODULE_ALIAS_SCSI_DEVICE(TYPE_DISK);
 MODULE_ALIAS_SCSI_DEVICE(TYPE_MOD);
 MODULE_ALIAS_SCSI_DEVICE(TYPE_RBC);
 
-static int  sd_revalidate_disk(struct gendisk *);
-static int  sd_probe(struct device *);
-static int  sd_remove(struct device *);
-static void sd_shutdown(struct device *);
-static int sd_suspend(struct device *, pm_message_t state);
-static int sd_resume(struct device *);
-static void sd_rescan(struct device *);
-static int sd_done(struct scsi_cmnd *);
-static void sd_read_capacity(struct scsi_disk *sdkp, unsigned char *buffer);
-static void scsi_disk_release(struct class_device *cdev);
-static void sd_print_sense_hdr(struct scsi_disk *, struct scsi_sense_hdr *);
-static void sd_print_result(struct scsi_disk *, int);
-
 static DEFINE_IDR(sd_index_idr);
 static DEFINE_SPINLOCK(sd_index_lock);
 
@@ -253,7 +240,6 @@ static struct scsi_driver sd_template = {
                 .shutdown       = sd_shutdown,
         },
         .rescan                 = sd_rescan,
-        .done                   = sd_done,
 };
 
 /*
@@ -523,6 +509,12 @@ static int sd_prep_fn(struct request_queue *q, struct request *rq)
         SCpnt->timeout_per_command = timeout;
 
         /*
+         * This is the completion routine we use.  This is matched in terms
+         * of capability to this function.
+         */
+        SCpnt->done = sd_rw_intr;
+
+        /*
          * This indicates that the command is ready from our end to be
          * queued.
          */
@@ -895,13 +887,13 @@ static struct block_device_operations sd_fops = {
 };
 
 /**
- *      sd_done - bottom half handler: called when the lower level
+ *      sd_rw_intr - bottom half handler: called when the lower level
  *      driver has completed (successfully or otherwise) a scsi command.
  *      @SCpnt: mid-level's per command structure.
  *
  *      Note: potentially run from within an ISR. Must not block.
  **/
-static int sd_done(struct scsi_cmnd *SCpnt)
+static void sd_rw_intr(struct scsi_cmnd * SCpnt)
 {
         int result = SCpnt->result;
         unsigned int xfer_size = SCpnt->request_bufflen;
@@ -922,7 +914,7 @@ static int sd_done(struct scsi_cmnd *SCpnt)
         SCSI_LOG_HLCOMPLETE(1, scsi_print_result(SCpnt));
         if (sense_valid) {
                 SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, SCpnt,
-                                                   "sd_done: sb[respc,sk,asc,"
+                                                   "sd_rw_intr: sb[respc,sk,asc,"
                                                    "ascq]=%x,%x,%x,%x\n",
                                                    sshdr.response_code,
                                                    sshdr.sense_key, sshdr.asc,
@@ -994,7 +986,7 @@ static int sd_done(struct scsi_cmnd *SCpnt)
                 break;
         }
  out:
-        return good_bytes;
+        scsi_io_completion(SCpnt, good_bytes);
 }
 
 static int media_not_present(struct scsi_disk *sdkp,
diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c
index c6199903114..a0c4e13d4da 100644
--- a/drivers/scsi/sr.c
+++ b/drivers/scsi/sr.c
@@ -78,7 +78,6 @@ MODULE_ALIAS_SCSI_DEVICE(TYPE_WORM);
 
 static int sr_probe(struct device *);
 static int sr_remove(struct device *);
-static int sr_done(struct scsi_cmnd *);
 
 static struct scsi_driver sr_template = {
         .owner                  = THIS_MODULE,
@@ -87,7 +86,6 @@ static struct scsi_driver sr_template = {
                 .probe          = sr_probe,
                 .remove         = sr_remove,
         },
-        .done                   = sr_done,
 };
 
 static unsigned long sr_index_bits[SR_DISKS / BITS_PER_LONG];
@@ -210,12 +208,12 @@ static int sr_media_change(struct cdrom_device_info *cdi, int slot)
 }
  
 /*
- * sr_done is the interrupt routine for the device driver.
+ * rw_intr is the interrupt routine for the device driver.
  *
- * It will be notified on the end of a SCSI read / write, and will take one
+ * It will be notified on the end of a SCSI read / write, and will take on
  * of several actions based on success or failure.
  */
-static int sr_done(struct scsi_cmnd *SCpnt)
+static void rw_intr(struct scsi_cmnd * SCpnt)
 {
         int result = SCpnt->result;
         int this_count = SCpnt->request_bufflen;
@@ -288,7 +286,12 @@ static int sr_done(struct scsi_cmnd *SCpnt)
                 }
         }
 
-        return good_bytes;
+        /*
+         * This calls the generic completion function, now that we know
+         * how many actual sectors finished, and how many sectors we need
+         * to say have failed.
+         */
+        scsi_io_completion(SCpnt, good_bytes);
 }
 
 static int sr_prep_fn(struct request_queue *q, struct request *rq)
@@ -425,6 +428,12 @@ static int sr_prep_fn(struct request_queue *q, struct request *rq)
         SCpnt->timeout_per_command = timeout;
 
         /*
+         * This is the completion routine we use.  This is matched in terms
+         * of capability to this function.
+         */
+        SCpnt->done = rw_intr;
+
+        /*
          * This indicates that the command is ready from our end to be
          * queued.
          */
diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
index 3f47e522a1e..7613c298937 100644
--- a/include/scsi/scsi_cmnd.h
+++ b/include/scsi/scsi_cmnd.h
@@ -34,6 +34,7 @@ struct scsi_cmnd {
         struct list_head list;  /* scsi_cmnd participates in queue lists */
         struct list_head eh_entry; /* entry for the host eh_cmd_q */
         int eh_eflags;          /* Used by error handlr */
+        void (*done) (struct scsi_cmnd *);      /* Mid-level done function */
 
         /*
          * A SCSI Command is assigned a nonzero serial_number before passed
@@ -121,6 +122,7 @@ extern struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *, gfp_t);
 extern void scsi_put_command(struct scsi_cmnd *);
 extern void __scsi_put_command(struct Scsi_Host *, struct scsi_cmnd *,
                                struct device *);
+extern void scsi_io_completion(struct scsi_cmnd *, unsigned int);
 extern void scsi_finish_command(struct scsi_cmnd *cmd);
 extern void scsi_req_abort_cmd(struct scsi_cmnd *cmd);
 
diff --git a/include/scsi/scsi_driver.h b/include/scsi/scsi_driver.h
index 1f5ca7f6211..56a304709fd 100644
--- a/include/scsi/scsi_driver.h
+++ b/include/scsi/scsi_driver.h
@@ -15,7 +15,6 @@ struct scsi_driver {
         struct device_driver    gendrv;
 
         void (*rescan)(struct device *);
-        int (*done)(struct scsi_cmnd *);
 };
 #define to_scsi_driver(drv) \
         container_of((drv), struct scsi_driver, gendrv)
diff --git a/include/scsi/sd.h b/include/scsi/sd.h
index f7513313ef0..aa1e7161301 100644
--- a/include/scsi/sd.h
+++ b/include/scsi/sd.h
@@ -47,6 +47,19 @@ struct scsi_disk {
 };
 #define to_scsi_disk(obj) container_of(obj,struct scsi_disk,cdev)
 
+static int  sd_revalidate_disk(struct gendisk *disk);
+static void sd_rw_intr(struct scsi_cmnd * SCpnt);
+static int  sd_probe(struct device *);
+static int  sd_remove(struct device *);
+static void sd_shutdown(struct device *dev);
+static int sd_suspend(struct device *dev, pm_message_t state);
+static int sd_resume(struct device *dev);
+static void sd_rescan(struct device *);
+static void sd_read_capacity(struct scsi_disk *sdkp, unsigned char *buffer);
+static void scsi_disk_release(struct class_device *cdev);
+static void sd_print_sense_hdr(struct scsi_disk *, struct scsi_sense_hdr *);
+static void sd_print_result(struct scsi_disk *, int);
+
 #define sd_printk(prefix, sdsk, fmt, a...)                              \
         (sdsk)->disk ?                                                  \
         sdev_printk(prefix, (sdsk)->device, "[%s] " fmt,                \