From: Mike Anderson <andmike@us.ibm.com>
Date: Thu, 16 Jun 2005 18:14:33 +0000 (-0700)
Subject: [SCSI] host state model update: mediate host add/remove race
X-Git-Tag: v2.6.14-rc1~522^2~12^2~55
X-Git-Url: http://www.pilppa.org/gitweb/gitweb.cgi?a=commitdiff_plain;h=82f29467a025f6a2192d281e97fca0be46e905cc;p=linux-2.6-omap-h63xx.git

[SCSI] host state model update: mediate host add/remove race

Add support to not allow additions to a host when it is being removed.

Signed-off-by: Mike Anderson <andmike@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
---

diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
index 67c4c0c3aa5..8640ad1c17e 100644
--- a/drivers/scsi/hosts.c
+++ b/drivers/scsi/hosts.c
@@ -133,7 +133,9 @@ EXPORT_SYMBOL(scsi_host_set_state);
  **/
 void scsi_remove_host(struct Scsi_Host *shost)
 {
+	down(&shost->scan_mutex);
 	scsi_host_set_state(shost, SHOST_CANCEL);
+	up(&shost->scan_mutex);
 	scsi_forget_host(shost);
 	scsi_proc_host_rm(shost);
 
diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index 2d3c4ac475f..076cbe3b5a0 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -1251,9 +1251,12 @@ struct scsi_device *__scsi_add_device(struct Scsi_Host *shost, uint channel,
 
 	get_device(&starget->dev);
 	down(&shost->scan_mutex);
-	res = scsi_probe_and_add_lun(starget, lun, NULL, &sdev, 1, hostdata);
-	if (res != SCSI_SCAN_LUN_PRESENT)
-		sdev = ERR_PTR(-ENODEV);
+	if (scsi_host_scan_allowed(shost)) {
+		res = scsi_probe_and_add_lun(starget, lun, NULL, &sdev, 1,
+					     hostdata);
+		if (res != SCSI_SCAN_LUN_PRESENT)
+			sdev = ERR_PTR(-ENODEV);
+	}
 	up(&shost->scan_mutex);
 	scsi_target_reap(starget);
 	put_device(&starget->dev);
@@ -1403,11 +1406,15 @@ int scsi_scan_host_selected(struct Scsi_Host *shost, unsigned int channel,
 		return -EINVAL;
 
 	down(&shost->scan_mutex);
-	if (channel == SCAN_WILD_CARD) 
-		for (channel = 0; channel <= shost->max_channel; channel++)
+	if (scsi_host_scan_allowed(shost)) {
+		if (channel == SCAN_WILD_CARD)
+			for (channel = 0; channel <= shost->max_channel;
+			     channel++)
+				scsi_scan_channel(shost, channel, id, lun,
+						  rescan);
+		else
 			scsi_scan_channel(shost, channel, id, lun, rescan);
-	else
-		scsi_scan_channel(shost, channel, id, lun, rescan);
+	}
 	up(&shost->scan_mutex);
 
 	return 0;
diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index 0b1e275b269..1ea5b51d174 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -650,6 +650,15 @@ static inline struct device *scsi_get_device(struct Scsi_Host *shost)
         return shost->shost_gendev.parent;
 }
 
+/**
+ * scsi_host_scan_allowed - Is scanning of this host allowed
+ * @shost:	Pointer to Scsi_Host.
+ **/
+static inline int scsi_host_scan_allowed(struct Scsi_Host *shost)
+{
+	return shost->shost_state == SHOST_RUNNING;
+}
+
 extern void scsi_unblock_requests(struct Scsi_Host *);
 extern void scsi_block_requests(struct Scsi_Host *);