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authorKay Sievers <kay.sievers@vrfy.org>2011-06-30 17:03:48 +0400
committerJames Bottomley <JBottomley@Parallels.com>2011-07-22 01:15:58 +0400
commit79b9677d885d1a792bc103f2febb06f91f92de43 (patch)
tree5971cd5ec435ca750b8ba77929df53e1fd78dbad /drivers/scsi/sr.h
parent57a6fa9acd6b4a479a6ede4d6d2258f04afd3a6f (diff)
downloadlinux-79b9677d885d1a792bc103f2febb06f91f92de43.tar.xz
[SCSI] sr: check_events() ignore GET_EVENT when TUR says otherwise
Some broken devices indicates that media has changed on every GET_EVENT_STATUS_NOTIFICATION. This translates into MEDIA_CHANGE uevent on every open() which lets udev run into a loop. Verify GET_EVENT result against TUR and if it generates spurious events for several times in a row, ignore the GET_EVENT events, and trust only the TUR status. This is the log of a USB stick with a (broken) fake CDROM drive: scsi 5:0:0:0: Direct-Access SanDisk U3 Cruzer Micro 8.02 PQ: 0 ANSI: 0 CCS sd 5:0:0:0: Attached scsi generic sg3 type 0 scsi 5:0:0:1: CD-ROM SanDisk U3 Cruzer Micro 8.02 PQ: 0 ANSI: 0 sd 5:0:0:0: [sdb] Attached SCSI removable disk sr2: scsi3-mmc drive: 48x/48x tray sr 5:0:0:1: Attached scsi CD-ROM sr2 sr 5:0:0:1: Attached scsi generic sg4 type 5 sr2: GET_EVENT and TUR disagree continuously, suppress GET_EVENT events sd 5:0:0:0: [sdb] 31777279 512-byte logical blocks: (16.2 GB/15.1 GiB) sd 5:0:0:0: [sdb] No Caching mode page present sd 5:0:0:0: [sdb] Assuming drive cache: write through sd 5:0:0:0: [sdb] No Caching mode page present sd 5:0:0:0: [sdb] Assuming drive cache: write through sdb: sdb1 -tj: Updated to consider only spurious GET_EVENT events among different types of disagreement and allow using TUR for kernel event polling after GET_EVENT is ignored. Reported-By: Markus Rathgeb maggu2810@googlemail.com Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: stable@kernel.org # >= v2.6.38, fixes udev busy looping w/ certain devices Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Diffstat (limited to 'drivers/scsi/sr.h')
-rw-r--r--drivers/scsi/sr.h7
1 files changed, 7 insertions, 0 deletions
diff --git a/drivers/scsi/sr.h b/drivers/scsi/sr.h
index e036f1dc83c8..37c8f6b17510 100644
--- a/drivers/scsi/sr.h
+++ b/drivers/scsi/sr.h
@@ -41,6 +41,13 @@ typedef struct scsi_cd {
unsigned readcd_known:1; /* drive supports READ_CD (0xbe) */
unsigned readcd_cdda:1; /* reading audio data using READ_CD */
unsigned media_present:1; /* media is present */
+
+ /* GET_EVENT spurious event handling, blk layer guarantees exclusion */
+ int tur_mismatch; /* nr of get_event TUR mismatches */
+ bool tur_changed:1; /* changed according to TUR */
+ bool get_event_changed:1; /* changed according to GET_EVENT */
+ bool ignore_get_event:1; /* GET_EVENT is unreliable, use TUR */
+
struct cdrom_device_info cdi;
/* We hold gendisk and scsi_device references on probe and use
* the refs on this kref to decide when to release them */