alistair23-linux/drivers/scsi/sd.h
Martin K. Petersen 18a4d0a22e [SCSI] Handle disk devices which can not process medium access commands
We have experienced several devices which fail in a fashion we do not
currently handle gracefully in SCSI. After a failure these devices will
respond to the SCSI primary command set (INQUIRY, TEST UNIT READY, etc.)
but any command accessing the storage medium will time out.

The following patch adds an callback that can be used by upper level
drivers to inspect the results of an error handling command. This in
turn has been used to implement additional checking in the SCSI disk
driver.

If a medium access command fails twice but TEST UNIT READY succeeds both
times in the subsequent error handling we will offline the device. The
maximum number of failed commands required to take a device offline can
be tweaked in sysfs.

Also add a new error flag to scsi_debug which allows this scenario to be
easily reproduced.

[jejb: fix up integer parsing to use kstrtouint]
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-02-19 10:14:52 -06:00

178 lines
4.3 KiB
C

#ifndef _SCSI_DISK_H
#define _SCSI_DISK_H
/*
* More than enough for everybody ;) The huge number of majors
* is a leftover from 16bit dev_t days, we don't really need that
* much numberspace.
*/
#define SD_MAJORS 16
/*
* Time out in seconds for disks and Magneto-opticals (which are slower).
*/
#define SD_TIMEOUT (30 * HZ)
#define SD_MOD_TIMEOUT (75 * HZ)
#define SD_FLUSH_TIMEOUT (60 * HZ)
/*
* Number of allowed retries
*/
#define SD_MAX_RETRIES 5
#define SD_PASSTHROUGH_RETRIES 1
#define SD_MAX_MEDIUM_TIMEOUTS 2
/*
* Size of the initial data buffer for mode and read capacity data
*/
#define SD_BUF_SIZE 512
/*
* Number of sectors at the end of the device to avoid multi-sector
* accesses to in the case of last_sector_bug
*/
#define SD_LAST_BUGGY_SECTORS 8
enum {
SD_EXT_CDB_SIZE = 32, /* Extended CDB size */
SD_MEMPOOL_SIZE = 2, /* CDB pool size */
};
enum {
SD_LBP_FULL = 0, /* Full logical block provisioning */
SD_LBP_UNMAP, /* Use UNMAP command */
SD_LBP_WS16, /* Use WRITE SAME(16) with UNMAP bit */
SD_LBP_WS10, /* Use WRITE SAME(10) with UNMAP bit */
SD_LBP_ZERO, /* Use WRITE SAME(10) with zero payload */
SD_LBP_DISABLE, /* Discard disabled due to failed cmd */
};
struct scsi_disk {
struct scsi_driver *driver; /* always &sd_template */
struct scsi_device *device;
struct device dev;
struct gendisk *disk;
atomic_t openers;
sector_t capacity; /* size in 512-byte sectors */
u32 max_ws_blocks;
u32 max_unmap_blocks;
u32 unmap_granularity;
u32 unmap_alignment;
u32 index;
unsigned int physical_block_size;
unsigned int max_medium_access_timeouts;
unsigned int medium_access_timed_out;
u8 media_present;
u8 write_prot;
u8 protection_type;/* Data Integrity Field */
u8 provisioning_mode;
unsigned ATO : 1; /* state of disk ATO bit */
unsigned WCE : 1; /* state of disk WCE bit */
unsigned RCD : 1; /* state of disk RCD bit, unused */
unsigned DPOFUA : 1; /* state of disk DPOFUA bit */
unsigned first_scan : 1;
unsigned lbpme : 1;
unsigned lbprz : 1;
unsigned lbpu : 1;
unsigned lbpws : 1;
unsigned lbpws10 : 1;
unsigned lbpvpd : 1;
};
#define to_scsi_disk(obj) container_of(obj,struct scsi_disk,dev)
static inline struct scsi_disk *scsi_disk(struct gendisk *disk)
{
return container_of(disk->private_data, struct scsi_disk, driver);
}
#define sd_printk(prefix, sdsk, fmt, a...) \
(sdsk)->disk ? \
sdev_printk(prefix, (sdsk)->device, "[%s] " fmt, \
(sdsk)->disk->disk_name, ##a) : \
sdev_printk(prefix, (sdsk)->device, fmt, ##a)
static inline int scsi_medium_access_command(struct scsi_cmnd *scmd)
{
switch (scmd->cmnd[0]) {
case READ_6:
case READ_10:
case READ_12:
case READ_16:
case SYNCHRONIZE_CACHE:
case VERIFY:
case VERIFY_12:
case VERIFY_16:
case WRITE_6:
case WRITE_10:
case WRITE_12:
case WRITE_16:
case WRITE_SAME:
case WRITE_SAME_16:
case UNMAP:
return 1;
case VARIABLE_LENGTH_CMD:
switch (scmd->cmnd[9]) {
case READ_32:
case VERIFY_32:
case WRITE_32:
case WRITE_SAME_32:
return 1;
}
}
return 0;
}
/*
* A DIF-capable target device can be formatted with different
* protection schemes. Currently 0 through 3 are defined:
*
* Type 0 is regular (unprotected) I/O
*
* Type 1 defines the contents of the guard and reference tags
*
* Type 2 defines the contents of the guard and reference tags and
* uses 32-byte commands to seed the latter
*
* Type 3 defines the contents of the guard tag only
*/
enum sd_dif_target_protection_types {
SD_DIF_TYPE0_PROTECTION = 0x0,
SD_DIF_TYPE1_PROTECTION = 0x1,
SD_DIF_TYPE2_PROTECTION = 0x2,
SD_DIF_TYPE3_PROTECTION = 0x3,
};
/*
* Data Integrity Field tuple.
*/
struct sd_dif_tuple {
__be16 guard_tag; /* Checksum */
__be16 app_tag; /* Opaque storage */
__be32 ref_tag; /* Target LBA or indirect LBA */
};
#ifdef CONFIG_BLK_DEV_INTEGRITY
extern void sd_dif_config_host(struct scsi_disk *);
extern int sd_dif_prepare(struct request *rq, sector_t, unsigned int);
extern void sd_dif_complete(struct scsi_cmnd *, unsigned int);
#else /* CONFIG_BLK_DEV_INTEGRITY */
static inline void sd_dif_config_host(struct scsi_disk *disk)
{
}
static inline int sd_dif_prepare(struct request *rq, sector_t s, unsigned int a)
{
return 0;
}
static inline void sd_dif_complete(struct scsi_cmnd *cmd, unsigned int a)
{
}
#endif /* CONFIG_BLK_DEV_INTEGRITY */
#endif /* _SCSI_DISK_H */