[PATCH UPDATED 5/8] scsi: fix TUR error handling in sr_media_change()

From: Tejun Heo
Date: Thu Dec 09 2010 - 05:19:23 EST


sr_test_unit_ready() returns 0 iff TUR succeeded - IOW, when media is
present and the device is actually ready, so the return value wouldn't
be zero when TUR ends with sense data. sr_media_change() incorrectly
tests (retval || (scsi_sense_valid(sshdr)...)) when it tries to test
whether TUR failed without sense data or with sense data indicating
media-not-present.

Fix the test using scsi_status_is_good() and update comments.

- Fixed a comment typo spotted by Eike.

Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Cc: Rolf Eike Beer <eike-kernel@xxxxxxxxx>
---
Typo fixed. git tree updated accordingly. Thanks.

drivers/scsi/sr.c | 18 +++++++++++-------
1 file changed, 11 insertions(+), 7 deletions(-)

Index: work/drivers/scsi/sr.c
===================================================================
--- work.orig/drivers/scsi/sr.c
+++ work/drivers/scsi/sr.c
@@ -214,13 +214,17 @@ static int sr_media_change(struct cdrom_

sshdr = kzalloc(sizeof(*sshdr), GFP_KERNEL);
retval = sr_test_unit_ready(cd->device, sshdr);
- if (retval || (scsi_sense_valid(sshdr) &&
- /* 0x3a is medium not present */
- sshdr->asc == 0x3a)) {
- /* Media not present or unable to test, unit probably not
- * ready. This usually means there is no disc in the drive.
- * Mark as changed, and we will figure it out later once
- * the drive is available again.
+ /*
+ * Media is considered to be present if TUR succeeds or fails with
+ * sense data indicating something other than media-not-present
+ * (ASC 0x3a).
+ */
+ if (!scsi_status_is_good(retval) &&
+ (!scsi_sense_valid(sshdr) || sshdr->asc == 0x3a)) {
+ /*
+ * Probably no media in the device. Mark as changed, and
+ * we will figure it out later once the drive is available
+ * again.
*/
cd->device->changed = 1;
/* This will force a flush, if called from check_disk_change */
--
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