[SCSI] scsi_host_lookup: error returns and NULL pointers

This patch cleans up the behavior of scsi_host_lookup().

The original implementation attempted to use the dual role of
either returning a pointer value, or a negative error code.
User's needed to use IS_ERR() to check the result. Additionally,
the IS_ERR() macro never checks for when a NULL pointer was
returned, so a NULL pointer actually passes with a success case.
Note: scsi_host_get(), used by scsi_host_lookup(), can return
a NULL pointer.

Talk about a mudhole for the unitiated to step into....

This patch converts scsi_host_lookup() to return either NULL
or a valid pointer. The consumers were updated for the change.

Signed-off-by: James Smart <james.smart@emulex.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

1 files changed, 4 insertions, 4 deletions

diff --git a/drivers/scsi/scsi_proc.c b/drivers/scsi/scsi_proc.c
index c6a904a45bf9..82f7b2dd08a2 100644
--- a/drivers/scsi/scsi_proc.c
+++ b/drivers/scsi/scsi_proc.c
@@ -259,8 +259,8 @@ static int scsi_add_single_device(uint host, uint channel, uint id, uint lun)
 	int error = -ENXIO;
 
 	shost = scsi_host_lookup(host);
-	if (IS_ERR(shost))
-		return PTR_ERR(shost);
+	if (!shost)
+		return error;
 
 	if (shost->transportt->user_scan)
 		error = shost->transportt->user_scan(shost, channel, id, lun);
@@ -287,8 +287,8 @@ static int scsi_remove_single_device(uint host, uint channel, uint id, uint lun)
 	int error = -ENXIO;
 
 	shost = scsi_host_lookup(host);
-	if (IS_ERR(shost))
-		return PTR_ERR(shost);
+	if (!shost)
+		return error;
 	sdev = scsi_device_lookup(shost, channel, id, lun);
 	if (sdev) {
 		scsi_remove_device(sdev);