From: Jeremy Linton <jli@xxxxxxxxxxxxxxxxxx> Any function which use scsi_execute_async() and transfers "odd" sized data that doesn't align correctly with the segment sizes may have its transfer length padded out to the closest segment size. For writes, this results in unnecessary data being transfered to the SCSI target. For reads, it affects the residual data length being returned to the application since the residual length will be based on the padded transfer size rather than the actual request size. The easiest way to see this is by trying to read using the SG_IO ioctl a large (>32k) buffer size from a tape device that only has a few bytes of data stored for the current block. The resulting resid will generally be incorrect. I've fixed this simply by changing scsi_req_map_sg() so that it places the requested transfer length in rq->data_len rather than the sum of all the sg segments. Signed-off-by: Jeremy Linton <jli@xxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- drivers/scsi/scsi_lib.c | 2 +- 1 files changed, 1 insertion(+), 1 deletion(-) diff -puN drivers/scsi/scsi_lib.c~incorrect-scsi-transfer-length-computation-from-odd drivers/scsi/scsi_lib.c --- a/drivers/scsi/scsi_lib.c~incorrect-scsi-transfer-length-computation-from-odd +++ a/drivers/scsi/scsi_lib.c @@ -355,7 +355,7 @@ static int scsi_req_map_sg(struct reques } rq->buffer = rq->data = NULL; - rq->data_len = data_len; + rq->data_len = bufflen; return 0; free_bios: _ - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
