[SCSI] sd/scsi_lib simplify sd_rw_intr and scsi_io_completion
This patch simplifies "good_bytes" computation in sd_rw_intr().
sd: "good_bytes" computation is always done in terms of the resolution
of the device's medium, since after that it is the number of good bytes
we pass around and other layers/contexts (as opposed ot sd) can translate
that to their own resolution (block layer:512). It also makes
scsi_io_completion() processing more straightforward, eliminating the
3rd argument to the function.
It also fixes a couple of bugs like not checking return value,
using "break" instead of "return;", etc.
I've been running with this patch for some time now on a
test (do-it-all) system.
Signed-off-by: Luben Tuikov <ltuikov@yahoo.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 3541990..f899ff0 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -891,11 +891,10 @@
static void sd_rw_intr(struct scsi_cmnd * SCpnt)
{
int result = SCpnt->result;
- int this_count = SCpnt->request_bufflen;
- int good_bytes = (result == 0 ? this_count : 0);
- sector_t block_sectors = 1;
- u64 first_err_block;
- sector_t error_sector;
+ unsigned int xfer_size = SCpnt->request_bufflen;
+ unsigned int good_bytes = result ? 0 : xfer_size;
+ u64 start_lba = SCpnt->request->sector;
+ u64 bad_lba;
struct scsi_sense_hdr sshdr;
int sense_valid = 0;
int sense_deferred = 0;
@@ -906,7 +905,6 @@
if (sense_valid)
sense_deferred = scsi_sense_is_deferred(&sshdr);
}
-
#ifdef CONFIG_SCSI_LOGGING
SCSI_LOG_HLCOMPLETE(1, printk("sd_rw_intr: %s: res=0x%x\n",
SCpnt->request->rq_disk->disk_name, result));
@@ -916,89 +914,72 @@
sshdr.sense_key, sshdr.asc, sshdr.ascq));
}
#endif
- /*
- Handle MEDIUM ERRORs that indicate partial success. Since this is a
- relatively rare error condition, no care is taken to avoid
- unnecessary additional work such as memcpy's that could be avoided.
- */
- if (driver_byte(result) != 0 &&
- sense_valid && !sense_deferred) {
- switch (sshdr.sense_key) {
- case MEDIUM_ERROR:
- if (!blk_fs_request(SCpnt->request))
- break;
- info_valid = scsi_get_sense_info_fld(
- SCpnt->sense_buffer, SCSI_SENSE_BUFFERSIZE,
- &first_err_block);
- /*
- * May want to warn and skip if following cast results
- * in actual truncation (if sector_t < 64 bits)
- */
- error_sector = (sector_t)first_err_block;
- if (SCpnt->request->bio != NULL)
- block_sectors = bio_sectors(SCpnt->request->bio);
- switch (SCpnt->device->sector_size) {
- case 1024:
- error_sector <<= 1;
- if (block_sectors < 2)
- block_sectors = 2;
- break;
- case 2048:
- error_sector <<= 2;
- if (block_sectors < 4)
- block_sectors = 4;
- break;
- case 4096:
- error_sector <<=3;
- if (block_sectors < 8)
- block_sectors = 8;
- break;
- case 256:
- error_sector >>= 1;
- break;
- default:
- break;
- }
+ if (driver_byte(result) != DRIVER_SENSE &&
+ (!sense_valid || sense_deferred))
+ goto out;
- error_sector &= ~(block_sectors - 1);
- good_bytes = (error_sector - SCpnt->request->sector) << 9;
- if (good_bytes < 0 || good_bytes >= this_count)
- good_bytes = 0;
+ switch (sshdr.sense_key) {
+ case HARDWARE_ERROR:
+ case MEDIUM_ERROR:
+ if (!blk_fs_request(SCpnt->request))
+ goto out;
+ info_valid = scsi_get_sense_info_fld(SCpnt->sense_buffer,
+ SCSI_SENSE_BUFFERSIZE,
+ &bad_lba);
+ if (!info_valid)
+ goto out;
+ if (xfer_size <= SCpnt->device->sector_size)
+ goto out;
+ switch (SCpnt->device->sector_size) {
+ case 256:
+ start_lba <<= 1;
break;
-
- case RECOVERED_ERROR: /* an error occurred, but it recovered */
- case NO_SENSE: /* LLDD got sense data */
- /*
- * Inform the user, but make sure that it's not treated
- * as a hard error.
- */
- scsi_print_sense("sd", SCpnt);
- SCpnt->result = 0;
- memset(SCpnt->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
- good_bytes = this_count;
+ case 512:
break;
-
- case ILLEGAL_REQUEST:
- if (SCpnt->device->use_10_for_rw &&
- (SCpnt->cmnd[0] == READ_10 ||
- SCpnt->cmnd[0] == WRITE_10))
- SCpnt->device->use_10_for_rw = 0;
- if (SCpnt->device->use_10_for_ms &&
- (SCpnt->cmnd[0] == MODE_SENSE_10 ||
- SCpnt->cmnd[0] == MODE_SELECT_10))
- SCpnt->device->use_10_for_ms = 0;
+ case 1024:
+ start_lba >>= 1;
break;
-
+ case 2048:
+ start_lba >>= 2;
+ break;
+ case 4096:
+ start_lba >>= 3;
+ break;
default:
+ /* Print something here with limiting frequency. */
+ goto out;
break;
}
+ /* This computation should always be done in terms of
+ * the resolution of the device's medium.
+ */
+ good_bytes = (bad_lba - start_lba)*SCpnt->device->sector_size;
+ break;
+ case RECOVERED_ERROR:
+ case NO_SENSE:
+ /* Inform the user, but make sure that it's not treated
+ * as a hard error.
+ */
+ scsi_print_sense("sd", SCpnt);
+ SCpnt->result = 0;
+ memset(SCpnt->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
+ good_bytes = xfer_size;
+ break;
+ case ILLEGAL_REQUEST:
+ if (SCpnt->device->use_10_for_rw &&
+ (SCpnt->cmnd[0] == READ_10 ||
+ SCpnt->cmnd[0] == WRITE_10))
+ SCpnt->device->use_10_for_rw = 0;
+ if (SCpnt->device->use_10_for_ms &&
+ (SCpnt->cmnd[0] == MODE_SENSE_10 ||
+ SCpnt->cmnd[0] == MODE_SELECT_10))
+ SCpnt->device->use_10_for_ms = 0;
+ break;
+ default:
+ break;
}
- /*
- * This calls the generic completion function, now that we know
- * how many actual sectors finished, and how many sectors we need
- * to say have failed.
- */
- scsi_io_completion(SCpnt, good_bytes, block_sectors << 9);
+ out:
+ scsi_io_completion(SCpnt, good_bytes);
}
static int media_not_present(struct scsi_disk *sdkp,