From: Damien Le Moal <damien.lemoal@xxxxxxx>
Re-shuffle the code to be more efficient by not initializing
variables upfront (i.e. do it only when necessary).
Also replace the do_div calls with calls to sectors_to_logical().
No functional change is introduced by this patch.
Signed-off-by: Damien Le Moal <damien.lemoal@xxxxxxx>
---
drivers/scsi/sd.c | 48 ++++++++++++++++++++++++++----------------------
1 file changed, 26 insertions(+), 22 deletions(-)
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index ce62d2c..10c7657 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1758,41 +1758,45 @@ static int sd_eh_action(struct scsi_cmnd *scmd, int eh_disp)
static unsigned int sd_completed_bytes(struct scsi_cmnd *scmd)
{
- u64 start_lba = blk_rq_pos(scmd->request);
- u64 end_lba = blk_rq_pos(scmd->request) + (scsi_bufflen(scmd) / 512);
- u64 factor = scmd->device->sector_size / 512;
- u64 bad_lba;
- int info_valid;
+ struct request *req = scmd->request;
+ struct scsi_device *sdev = scmd->device;
+ unsigned int transferred, good_bytes;
+ u64 start_lba, end_lba, bad_lba;
+
/*
- * resid is optional but mostly filled in. When it's unused,
- * its value is zero, so we assume the whole buffer transferred
+ * Some commands have a payload smaller than the device logical
+ * block size (e.g. INQUIRY on a 4K disk).
*/
- unsigned int transferred = scsi_bufflen(scmd) - scsi_get_resid(scmd);
- unsigned int good_bytes;
-
- info_valid = scsi_get_sense_info_fld(scmd->sense_buffer,
- SCSI_SENSE_BUFFERSIZE,
- &bad_lba);
- if (!info_valid)
+ if (scsi_bufflen(scmd) <= sdev->sector_size)
return 0;
- if (scsi_bufflen(scmd) <= scmd->device->sector_size)
+ /* Check if we have a 'bad_lba' information */
+ if (!scsi_get_sense_info_fld(scmd->sense_buffer,
+ SCSI_SENSE_BUFFERSIZE,
+ &bad_lba))
return 0;
- /* be careful ... don't want any overflows */
- do_div(start_lba, factor);
- do_div(end_lba, factor);
-
- /* The bad lba was reported incorrectly, we have no idea where
+ /*
+ * If the bad lba was reported incorrectly, we have no idea where
* the error is.
*/
- if (bad_lba < start_lba || bad_lba >= end_lba)
+ start_lba = sectors_to_logical(sdev, blk_rq_pos(req));
+ end_lba = sectors_to_logical(sdev,
+ blk_rq_pos(req) + (scsi_bufflen(scmd) >> 9));
+ if (bad_lba < start_lba || bad_lba >= end_lba)
return 0;
+ /*
+ * resid is optional but mostly filled in. When it's unused,
+ * its value is zero, so we assume the whole buffer transferred
+ */
+ transferred = scsi_bufflen(scmd) - scsi_get_resid(scmd);
+
/* This computation should always be done in terms of
* the resolution of the device's medium.
*/
- good_bytes = (bad_lba - start_lba) * scmd->device->sector_size;
+ good_bytes = logical_to_bytes(sdev, bad_lba - start_lba);
+
return min(good_bytes, transferred);
}
--
2.9.3
