--- drivers/scsi/sd.c

+++ drivers/scsi/sd.c

@@ -1040,6 +1040,12 @@ static unsigned int sd_completed_bytes(s

u64 end_lba = blk_rq_pos(scmd->request) + (scsi_bufflen(scmd) / 512);

u64 bad_lba;

int info_valid;

+ /*

+ * resid is optional but mostly filled in. When it's unused,

+ * its value is zero, so we assume the whole buffer transferred

+ */

+ unsigned int transferred = scsi_bufflen(scmd) - scsi_get_resid(scmd);

+ unsigned int good_bytes;

if (!blk_fs_request(scmd->request))

return 0;

@@ -1073,7 +1079,8 @@ static unsigned int sd_completed_bytes(s

/* This computation should always be done in terms of

* the resolution of the device's medium.

*/

- return (bad_lba - start_lba) * scmd->device->sector_size;

+ good_bytes = (bad_lba - start_lba) * scmd->device->sector_size;

+ return min(good_bytes, transferred);

}

/**