[PATCH] scsi: make "access_state" sysfs attribute always visible

[mwilck@suse.com]

From: Martin Wilck <mwilck@suse.com>

If a SCSI device handler module is loaded after some SCSI devices
have already been probed (e.g. via request_module() by dm-multipath),
the "access_state" and "preferred_path" sysfs attributes remain invisible for
these devices, although the handler is attached and live. The reason is
that the visibility is only checked when the sysfs attribute group is
first created. This results in an inconsistent user experience depending
on the load order of SCSI low-level drivers vs. device handler modules.

This patch changes user space API: attempting to read the "access_state"
or "preferred_path" attributes will now result in -EINVAL rather than
-ENODEV for devices that have no device handler, and tests for the existence
of these attributes will have a different result.

Signed-off-by: Martin Wilck <mwilck@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/scsi_sysfs.c | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index f1e0c131b77c..226a50944c00 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -1228,14 +1228,6 @@ static umode_t scsi_sdev_attr_is_visible(struct kobject *kobj,
 	    !sdev->host->hostt->change_queue_depth)
 		return 0;
 
-#ifdef CONFIG_SCSI_DH
-	if (attr == &dev_attr_access_state.attr &&
-	    !sdev->handler)
-		return 0;
-	if (attr == &dev_attr_preferred_path.attr &&
-	    !sdev->handler)
-		return 0;
-#endif
 	return attr->mode;
 }
 
-- 
2.34.1