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79b9677d88
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>
78 lines
2.5 KiB
C
78 lines
2.5 KiB
C
/*
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* sr.h by David Giller
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* CD-ROM disk driver header file
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*
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* adapted from:
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* sd.h Copyright (C) 1992 Drew Eckhardt
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* SCSI disk driver header file by
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* Drew Eckhardt
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*
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* <drew@colorado.edu>
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*
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* Modified by Eric Youngdale eric@andante.org to
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* add scatter-gather, multiple outstanding request, and other
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* enhancements.
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*/
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#ifndef _SR_H
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#define _SR_H
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#include <linux/genhd.h>
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#include <linux/kref.h>
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#define MAX_RETRIES 3
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#define SR_TIMEOUT (30 * HZ)
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struct scsi_device;
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/* The CDROM is fairly slow, so we need a little extra time */
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/* In fact, it is very slow if it has to spin up first */
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#define IOCTL_TIMEOUT 30*HZ
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typedef struct scsi_cd {
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struct scsi_driver *driver;
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unsigned capacity; /* size in blocks */
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struct scsi_device *device;
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unsigned int vendor; /* vendor code, see sr_vendor.c */
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unsigned long ms_offset; /* for reading multisession-CD's */
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unsigned use:1; /* is this device still supportable */
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unsigned xa_flag:1; /* CD has XA sectors ? */
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unsigned readcd_known:1; /* drive supports READ_CD (0xbe) */
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unsigned readcd_cdda:1; /* reading audio data using READ_CD */
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unsigned media_present:1; /* media is present */
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/* GET_EVENT spurious event handling, blk layer guarantees exclusion */
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int tur_mismatch; /* nr of get_event TUR mismatches */
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bool tur_changed:1; /* changed according to TUR */
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bool get_event_changed:1; /* changed according to GET_EVENT */
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bool ignore_get_event:1; /* GET_EVENT is unreliable, use TUR */
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struct cdrom_device_info cdi;
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/* We hold gendisk and scsi_device references on probe and use
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* the refs on this kref to decide when to release them */
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struct kref kref;
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struct gendisk *disk;
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} Scsi_CD;
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int sr_do_ioctl(Scsi_CD *, struct packet_command *);
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int sr_lock_door(struct cdrom_device_info *, int);
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int sr_tray_move(struct cdrom_device_info *, int);
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int sr_drive_status(struct cdrom_device_info *, int);
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int sr_disk_status(struct cdrom_device_info *);
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int sr_get_last_session(struct cdrom_device_info *, struct cdrom_multisession *);
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int sr_get_mcn(struct cdrom_device_info *, struct cdrom_mcn *);
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int sr_reset(struct cdrom_device_info *);
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int sr_select_speed(struct cdrom_device_info *cdi, int speed);
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int sr_audio_ioctl(struct cdrom_device_info *, unsigned int, void *);
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int sr_is_xa(Scsi_CD *);
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/* sr_vendor.c */
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void sr_vendor_init(Scsi_CD *);
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int sr_cd_check(struct cdrom_device_info *);
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int sr_set_blocklength(Scsi_CD *, int blocklength);
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#endif
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