[SCSI] scsi_dh: Implement match callback function
Some device handler types are not tied to the vendor/model
but rather to a specific capability. Eg ALUA is supported
if the 'TPGS' setting in the standard inquiry is set.
This patch implements a 'match' callback for device handler
which supersedes the original vendor/model lookup and
implements the callback for the ALUA handler.
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
diff --git a/drivers/scsi/device_handler/scsi_dh.c b/drivers/scsi/device_handler/scsi_dh.c
index fccd0f6..3ac71cf 100644
--- a/drivers/scsi/device_handler/scsi_dh.c
+++ b/drivers/scsi/device_handler/scsi_dh.c
@@ -60,6 +60,46 @@
}
/*
+ * device_handler_match_function - Match a device handler to a device
+ * @sdev - SCSI device to be tested
+ *
+ * Tests @sdev against the match function of all registered device_handler.
+ * Returns the found device handler or NULL if not found.
+ */
+static struct scsi_device_handler *
+device_handler_match_function(struct scsi_device *sdev)
+{
+ struct scsi_device_handler *tmp_dh, *found_dh = NULL;
+
+ spin_lock(&list_lock);
+ list_for_each_entry(tmp_dh, &scsi_dh_list, list) {
+ if (tmp_dh->match && tmp_dh->match(sdev)) {
+ found_dh = tmp_dh;
+ break;
+ }
+ }
+ spin_unlock(&list_lock);
+ return found_dh;
+}
+
+/*
+ * device_handler_match_devlist - Match a device handler to a device
+ * @sdev - SCSI device to be tested
+ *
+ * Tests @sdev against all device_handler registered in the devlist.
+ * Returns the found device handler or NULL if not found.
+ */
+static struct scsi_device_handler *
+device_handler_match_devlist(struct scsi_device *sdev)
+{
+ int idx;
+
+ idx = scsi_get_device_flags_keyed(sdev, sdev->vendor, sdev->model,
+ SCSI_DEVINFO_DH);
+ return get_device_handler_by_idx(idx);
+}
+
+/*
* device_handler_match - Attach a device handler to a device
* @scsi_dh - The device handler to match against or NULL
* @sdev - SCSI device to be tested against @scsi_dh
@@ -72,12 +112,11 @@
device_handler_match(struct scsi_device_handler *scsi_dh,
struct scsi_device *sdev)
{
- struct scsi_device_handler *found_dh = NULL;
- int idx;
+ struct scsi_device_handler *found_dh;
- idx = scsi_get_device_flags_keyed(sdev, sdev->vendor, sdev->model,
- SCSI_DEVINFO_DH);
- found_dh = get_device_handler_by_idx(idx);
+ found_dh = device_handler_match_function(sdev);
+ if (!found_dh)
+ found_dh = device_handler_match_devlist(sdev);
if (scsi_dh && found_dh != scsi_dh)
found_dh = NULL;
@@ -327,7 +366,7 @@
list_add(&scsi_dh->list, &scsi_dh_list);
spin_unlock(&list_lock);
- for (i = 0; scsi_dh->devlist[i].vendor; i++) {
+ for (i = 0; scsi_dh->devlist && scsi_dh->devlist[i].vendor; i++) {
scsi_dev_info_list_add_keyed(0,
scsi_dh->devlist[i].vendor,
scsi_dh->devlist[i].model,
@@ -360,7 +399,7 @@
bus_for_each_dev(&scsi_bus_type, NULL, scsi_dh,
scsi_dh_notifier_remove);
- for (i = 0; scsi_dh->devlist[i].vendor; i++) {
+ for (i = 0; scsi_dh->devlist && scsi_dh->devlist[i].vendor; i++) {
scsi_dev_info_list_del_keyed(scsi_dh->devlist[i].vendor,
scsi_dh->devlist[i].model,
SCSI_DEVINFO_DH);