From: Jens Axboe <jens.axboe@oracle.com>
Date: Mon, 27 Oct 2008 18:20:59 +0000 (+0100)
Subject: scsi: make sure that scsi_init_shared_tag_map() doesn't overwrite existing map
X-Git-Tag: v3.12-rc1~17477^2~1
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=3070f69b66b7ab2f02d8a2500edae07039c38508;p=kernel%2Fkernel-generic.git

scsi: make sure that scsi_init_shared_tag_map() doesn't overwrite existing map

Right now callers have to check whether scsi_host->bqt is already
set up, it's much cleaner to just have scsi_init_shared_tag_map()
does this check on its own.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
---

diff --git a/include/scsi/scsi_tcq.h b/include/scsi/scsi_tcq.h
index cf4c219..1723138 100644
--- a/include/scsi/scsi_tcq.h
+++ b/include/scsi/scsi_tcq.h
@@ -140,8 +140,18 @@ static inline struct scsi_cmnd *scsi_find_tag(struct scsi_device *sdev, int tag)
  */
 static inline int scsi_init_shared_tag_map(struct Scsi_Host *shost, int depth)
 {
-	shost->bqt = blk_init_tags(depth);
-	return shost->bqt ? 0 : -ENOMEM;
+	/*
+	 * If the shared tag map isn't already initialized, do it now.
+	 * This saves callers from having to check ->bqt when setting up
+	 * devices on the shared host (for libata)
+	 */
+	if (!shost->bqt) {
+		shost->bqt = blk_init_tags(depth);
+		if (!shost->bqt)
+			return -ENOMEM;
+	}
+
+	return 0;
 }
 
 /**