From: James Bottomley <James.Bottomley@HansenPartnership.com>
Date: Fri, 12 Sep 2008 21:46:51 +0000 (-0500)
Subject: [SCSI] scsi_error: fix target reset handling
X-Git-Tag: v2.6.28-rc1~263^2~12
X-Git-Url: http://www.pilppa.org/gitweb/gitweb.cgi?a=commitdiff_plain;h=c82dc88ddaf17112841dd3a6b08352968555ee08;p=linux-2.6-omap-h63xx.git

[SCSI] scsi_error: fix target reset handling

There's a target reset bug.

This loop:

	for (id = 0; id <= shost->max_id; id++) {

Never terminates if shost->max_id is set to ~0, like aic94xx does.

It's also pretty inefficient since you mostly have compact target
numbers, but the max_id can be very high.  The best way would be to
sort the recovery list by target id and skip them if they're equal,
but even a worst case O(N^2) traversal is probably OK here, so fix it
by finding the next highest target number (assuming n+1) and
terminating when there isn't one.

Cc: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
---

diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index ad019ece213..94ed262bdf0 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -1065,10 +1065,10 @@ static int scsi_eh_target_reset(struct Scsi_Host *shost,
 				struct list_head *done_q)
 {
 	struct scsi_cmnd *scmd, *tgtr_scmd, *next;
-	unsigned int id;
+	unsigned int id = 0;
 	int rtn;
 
-	for (id = 0; id <= shost->max_id; id++) {
+	do {
 		tgtr_scmd = NULL;
 		list_for_each_entry(scmd, work_q, eh_entry) {
 			if (id == scmd_id(scmd)) {
@@ -1076,8 +1076,18 @@ static int scsi_eh_target_reset(struct Scsi_Host *shost,
 				break;
 			}
 		}
+		if (!tgtr_scmd) {
+			/* not one exactly equal; find the next highest */
+			list_for_each_entry(scmd, work_q, eh_entry) {
+				if (scmd_id(scmd) > id &&
+				    (!tgtr_scmd ||
+				     scmd_id(tgtr_scmd) > scmd_id(scmd)))
+						tgtr_scmd = scmd;
+			}
+		}
 		if (!tgtr_scmd)
-			continue;
+			/* no more commands, that's it */
+			break;
 
 		SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending target reset "
 						  "to target %d\n",
@@ -1096,7 +1106,8 @@ static int scsi_eh_target_reset(struct Scsi_Host *shost,
 							  " failed target: "
 							  "%d\n",
 							  current->comm, id));
-	}
+		id++;
+	} while(id != 0);
 
 	return list_empty(work_q);
 }