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| author | James Bottomley <James.Bottomley@suse.de> | 2010-04-01 10:30:01 -0400 |
|---|---|---|
| committer | James Bottomley <James.Bottomley@suse.de> | 2010-04-11 13:36:26 -0500 |
| commit | 3233ac19811fe17033b537832ca7b59df8bf4aa9 (patch) | |
| tree | 33c316cf6821d8c3a98624266324d318d50c47fb /drivers/scsi/sd.c | |
| parent | 1469585309bb52869cbaa449c6d2cd1ce9869cca (diff) | |
| download | lwn-3233ac19811fe17033b537832ca7b59df8bf4aa9.tar.gz lwn-3233ac19811fe17033b537832ca7b59df8bf4aa9.zip | |
[SCSI] sd: retry read_capacity on UNIT_ATTENTION
Hazard testing uncovered yet another bug in sd. Under heavy reset
activity the retry counter might be exhausted and the command will be
returned with sense UNIT_ATTENTION/0x29/00 (POWER ON, RESET, OR BUS
DEVICE RESET OCCURRED). In those cases we should just increase the
retry counter again, retrying one more to clear up this Unit Attention
state.
[jejb: update to work with RC16 devices and not to loop endlessly]
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Diffstat (limited to 'drivers/scsi/sd.c')
| -rw-r--r-- | drivers/scsi/sd.c | 23 |
1 files changed, 20 insertions, 3 deletions
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index 7955bc226125..015a597a852e 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -1433,6 +1433,8 @@ static void read_capacity_error(struct scsi_disk *sdkp, struct scsi_device *sdp, #error RC16_LEN must not be more than SD_BUF_SIZE #endif +#define READ_CAPACITY_RETRIES_ON_RESET 10 + static int read_capacity_16(struct scsi_disk *sdkp, struct scsi_device *sdp, unsigned char *buffer) { @@ -1440,7 +1442,7 @@ static int read_capacity_16(struct scsi_disk *sdkp, struct scsi_device *sdp, struct scsi_sense_hdr sshdr; int sense_valid = 0; int the_result; - int retries = 3; + int retries = 3, reset_retries = READ_CAPACITY_RETRIES_ON_RESET; unsigned int alignment; unsigned long long lba; unsigned sector_size; @@ -1469,6 +1471,13 @@ static int read_capacity_16(struct scsi_disk *sdkp, struct scsi_device *sdp, * Invalid Field in CDB, just retry * silently with RC10 */ return -EINVAL; + if (sense_valid && + sshdr.sense_key == UNIT_ATTENTION && + sshdr.asc == 0x29 && sshdr.ascq == 0x00) + /* Device reset might occur several times, + * give it one more chance */ + if (--reset_retries > 0) + continue; } retries--; @@ -1527,7 +1536,7 @@ static int read_capacity_10(struct scsi_disk *sdkp, struct scsi_device *sdp, struct scsi_sense_hdr sshdr; int sense_valid = 0; int the_result; - int retries = 3; + int retries = 3, reset_retries = READ_CAPACITY_RETRIES_ON_RESET; sector_t lba; unsigned sector_size; @@ -1543,8 +1552,16 @@ static int read_capacity_10(struct scsi_disk *sdkp, struct scsi_device *sdp, if (media_not_present(sdkp, &sshdr)) return -ENODEV; - if (the_result) + if (the_result) { sense_valid = scsi_sense_valid(&sshdr); + if (sense_valid && + sshdr.sense_key == UNIT_ATTENTION && + sshdr.asc == 0x29 && sshdr.ascq == 0x00) + /* Device reset might occur several times, + * give it one more chance */ + if (--reset_retries > 0) + continue; + } retries--; } while (the_result && retries); |