[PATCH] scsi: remove meaningless scsi_cmnd->serial_number_at_timeout field

scsi_cmnd->serial_number_at_timeout doesn't serve any purpose
anymore.  All serial_number == serial_number_at_timeout tests
are always true in abort callbacks.  Kill the field.  Also, as
->pid always equals ->serial_number and ->serial_number
doesn't have any special meaning anymore, update comments
above ->serial_number accordingly.  Once we remove all uses of
this field from all lldd's, this field should go.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

10 files changed, 15 insertions, 62 deletions

diff --git a/drivers/scsi/BusLogic.c b/drivers/scsi/BusLogic.c
index 41b5197ce4e6..15e4b122d56e 100644
--- a/drivers/scsi/BusLogic.c
+++ b/drivers/scsi/BusLogic.c
@@ -2958,13 +2958,6 @@ static int BusLogic_AbortCommand(struct scsi_cmnd *Command)
         struct BusLogic_CCB *CCB;
         BusLogic_IncrementErrorCounter(&HostAdapter->TargetStatistics[TargetID].CommandAbortsRequested);
         /*
-           If this Command has already completed, then no Abort is necessary.
-         */
-        if (Command->serial_number != Command->serial_number_at_timeout) {
-                BusLogic_Warning("Unable to Abort Command to Target %d - " "Already Completed\n", HostAdapter, TargetID);
-                return SUCCESS;
-        }
-        /*
            Attempt to find an Active CCB for this Command.  If no Active CCB for this
            Command is found, then no Abort is necessary.
          */
diff --git a/drivers/scsi/advansys.c b/drivers/scsi/advansys.c
index edeb333d8161..04cb5c405a2d 100644
--- a/drivers/scsi/advansys.c
+++ b/drivers/scsi/advansys.c
@@ -9198,9 +9198,8 @@ asc_prt_scsi_cmnd(struct scsi_cmnd *s)
         s->use_sg, s->sglist_len, s->abort_reason);
 
     printk(
-" serial_number 0x%x, serial_number_at_timeout 0x%x, retries %d, allowed %d\n",
-        (unsigned) s->serial_number, (unsigned) s->serial_number_at_timeout,
-         s->retries, s->allowed);
+" serial_number 0x%x, retries %d, allowed %d\n",
+        (unsigned) s->serial_number, s->retries, s->allowed);
 
     printk(
 " timeout_per_command %d, timeout_total %d, timeout %d\n",
diff --git a/drivers/scsi/ips.c b/drivers/scsi/ips.c
index e46096da8db2..47c263e5cd39 100644
--- a/drivers/scsi/ips.c
+++ b/drivers/scsi/ips.c
@@ -833,13 +833,6 @@ ips_eh_abort(Scsi_Cmnd * SC)
         if (!ha->active)
                 return (FAILED);
 
-        if (SC->serial_number != SC->serial_number_at_timeout) {
-                /* HMM, looks like a bogus command */
-                DEBUG(1, "Abort called with bogus scsi command");
-
-                return (FAILED);
-        }
-
         /* See if the command is on the copp queue */
         item = ha->copp_waitlist.head;
         while ((item) && (item->scsi_cmd != SC))
diff --git a/drivers/scsi/ncr53c8xx.c b/drivers/scsi/ncr53c8xx.c
index 7ae13236788e..2a0e42ec27d3 100644
--- a/drivers/scsi/ncr53c8xx.c
+++ b/drivers/scsi/ncr53c8xx.c
@@ -7486,24 +7486,14 @@ static int ncr53c8xx_abort(struct scsi_cmnd *cmd)
         struct scsi_cmnd *done_list;
 
 #if defined SCSI_RESET_SYNCHRONOUS && defined SCSI_RESET_ASYNCHRONOUS
-        printk("ncr53c8xx_abort: pid=%lu serial_number=%ld serial_number_at_timeout=%ld\n",
-                cmd->pid, cmd->serial_number, cmd->serial_number_at_timeout);
+        printk("ncr53c8xx_abort: pid=%lu serial_number=%ld\n",
+                cmd->pid, cmd->serial_number);
 #else
         printk("ncr53c8xx_abort: command pid %lu\n", cmd->pid);
 #endif
 
         NCR_LOCK_NCB(np, flags);
 
-#if defined SCSI_RESET_SYNCHRONOUS && defined SCSI_RESET_ASYNCHRONOUS
-        /*
-         * We have to just ignore abort requests in some situations.
-         */
-        if (cmd->serial_number != cmd->serial_number_at_timeout) {
-                sts = SCSI_ABORT_NOT_RUNNING;
-                goto out;
-        }
-#endif
-
         sts = ncr_abort_command(np, cmd);
 out:
         done_list     = np->done_list;
diff --git a/drivers/scsi/qla2xxx/qla_dbg.c b/drivers/scsi/qla2xxx/qla_dbg.c
index dcc33daa5913..0e8ebbc56e81 100644
--- a/drivers/scsi/qla2xxx/qla_dbg.c
+++ b/drivers/scsi/qla2xxx/qla_dbg.c
@@ -1050,10 +1050,8 @@ qla2x00_print_scsi_cmd(struct scsi_cmnd * cmd)
         for (i = 0; i < cmd->cmd_len; i++) {
                 printk("0x%02x ", cmd->cmnd[i]);
         }
-        printk("\n  seg_cnt=%d, allowed=%d, retries=%d, "
-            "serial_number_at_timeout=0x%lx\n",
-            cmd->use_sg, cmd->allowed, cmd->retries,
-            cmd->serial_number_at_timeout);
+        printk("\n  seg_cnt=%d, allowed=%d, retries=%d\n",
+            cmd->use_sg, cmd->allowed, cmd->retries);
         printk("  request buffer=0x%p, request buffer len=0x%x\n",
             cmd->request_buffer, cmd->request_bufflen);
         printk("  tag=%d, transfersize=0x%x\n",
diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index 95de4d0f4fd1..05d2bd075fd4 100644
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -686,7 +686,6 @@ void scsi_init_cmd_from_req(struct scsi_cmnd *cmd, struct scsi_request *sreq)
         cmd->request = sreq->sr_request;
         memcpy(cmd->data_cmnd, sreq->sr_cmnd, sizeof(cmd->data_cmnd));
         cmd->serial_number = 0;
-        cmd->serial_number_at_timeout = 0;
         cmd->bufflen = sreq->sr_bufflen;
         cmd->buffer = sreq->sr_buffer;
         cmd->retries = 0;
@@ -765,7 +764,6 @@ void __scsi_done(struct scsi_cmnd *cmd)
          * Set the serial numbers back to zero
          */
         cmd->serial_number = 0;
-        cmd->serial_number_at_timeout = 0;
         cmd->state = SCSI_STATE_BHQUEUE;
         cmd->owner = SCSI_OWNER_BH_HANDLER;
 
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index 173abb88e3e8..13bac93fc397 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -79,11 +79,6 @@ int scsi_eh_scmd_add(struct scsi_cmnd *scmd, int eh_flag)
          */
         scmd->owner = SCSI_OWNER_ERROR_HANDLER;
         scmd->state = SCSI_STATE_FAILED;
-        /*
-         * Set the serial_number_at_timeout to the current
-         * serial_number
-         */
-        scmd->serial_number_at_timeout = scmd->serial_number;
         list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q);
         set_bit(SHOST_RECOVERY, &shost->shost_state);
         shost->host_failed++;
@@ -1061,7 +1056,6 @@ static int scsi_try_bus_reset(struct scsi_cmnd *scmd)
         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Bus RST\n",
                                           __FUNCTION__));
         scmd->owner = SCSI_OWNER_LOWLEVEL;
-        scmd->serial_number_at_timeout = scmd->serial_number;
 
         if (!scmd->device->host->hostt->eh_bus_reset_handler)
                 return FAILED;
@@ -1093,7 +1087,6 @@ static int scsi_try_host_reset(struct scsi_cmnd *scmd)
         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Host RST\n",
                                           __FUNCTION__));
         scmd->owner = SCSI_OWNER_LOWLEVEL;
-        scmd->serial_number_at_timeout = scmd->serial_number;
 
         if (!scmd->device->host->hostt->eh_host_reset_handler)
                 return FAILED;
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 19dd911d9f7a..619d3fb7a2f0 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -298,7 +298,6 @@ static int scsi_init_cmd_errh(struct scsi_cmnd *cmd)
 {
         cmd->owner = SCSI_OWNER_MIDLEVEL;
         cmd->serial_number = 0;
-        cmd->serial_number_at_timeout = 0;
         cmd->abort_reason = 0;
 
         memset(cmd->sense_buffer, 0, sizeof cmd->sense_buffer);
diff --git a/drivers/scsi/sym53c8xx_2/sym_glue.c b/drivers/scsi/sym53c8xx_2/sym_glue.c
index a1dff6d437bc..5ff83d214f12 100644
--- a/drivers/scsi/sym53c8xx_2/sym_glue.c
+++ b/drivers/scsi/sym53c8xx_2/sym_glue.c
@@ -799,12 +799,6 @@ static int sym_eh_handler(int op, char *opname, struct scsi_cmnd *cmd)
 
         dev_warn(&cmd->device->sdev_gendev, "%s operation started.\n", opname);
 
-#if 0
-        /* This one should be the result of some race, thus to ignore */
-        if (cmd->serial_number != cmd->serial_number_at_timeout)
-                goto prepare;
-#endif
-
         /* This one is queued in some place -> to wait for completion */
         FOR_EACH_QUEUED_ELEMENT(&np->busy_ccbq, qp) {
                 struct sym_ccb *cp = sym_que_entry(qp, struct sym_ccb, link_ccbq);
diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
index ae45d6f8f98c..07f5c699eaa7 100644
--- a/include/scsi/scsi_cmnd.h
+++ b/include/scsi/scsi_cmnd.h
@@ -43,21 +43,17 @@ struct scsi_cmnd {
         void (*done) (struct scsi_cmnd *);      /* Mid-level done function */
 
         /*
-         * A SCSI Command is assigned a nonzero serial_number when internal_cmnd
-         * passes it to the driver's queue command function.  The serial_number
-         * is cleared when scsi_done is entered indicating that the command has
-         * been completed.  If a timeout occurs, the serial number at the moment
-         * of timeout is copied into serial_number_at_timeout.  By subsequently
-         * comparing the serial_number and serial_number_at_timeout fields
-         * during abort or reset processing, we can detect whether the command
-         * has already completed.  This also detects cases where the command has
-         * completed and the SCSI Command structure has already being reused
-         * for another command, so that we can avoid incorrectly aborting or
-         * resetting the new command.
-         * The serial number is only unique per host.
+         * A SCSI Command is assigned a nonzero serial_number before passed
+         * to the driver's queue command function.  The serial_number is
+         * cleared when scsi_done is entered indicating that the command
+         * has been completed.  It currently doesn't have much use other
+         * than printk's.  Some lldd's use this number for other purposes.
+         * It's almost certain that such usages are either incorrect or
+         * meaningless.  Please kill all usages other than printk's.  Also,
+         * as this number is always identical to ->pid, please convert
+         * printk's to use ->pid, so that we can kill this field.
          */
         unsigned long serial_number;
-        unsigned long serial_number_at_timeout;
 
         int retries;
         int allowed;