4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Martin K. Petersen <martin.petersen@xxxxxxxxxx> commit 1d5de5bd311be7cd54f02f7cd164f0349a75c876 upstream. Commit a83da8a4509d ("scsi: sd: Optimal I/O size should be a multiple of physical block size") split one conditional into several separate statements in an effort to provide more accurate warning messages when a device reports a nonsensical value. However, this reorganization accidentally dropped the precondition of the reported value being larger than zero. This lead to a warning getting emitted on devices that do not report an optimal I/O size at all. Remain silent if a device does not report an optimal I/O size. Fixes: a83da8a4509d ("scsi: sd: Optimal I/O size should be a multiple of physical block size") Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Reported-by: Hussam Al-Tayeb <ht990332@xxxxxxx> Tested-by: Hussam Al-Tayeb <ht990332@xxxxxxx> Reviewed-by: Bart Van Assche <bvanassche@xxxxxxx> Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/scsi/sd.c | 3 +++ 1 file changed, 3 insertions(+) --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -2841,6 +2841,9 @@ static bool sd_validate_opt_xfer_size(st unsigned int opt_xfer_bytes = logical_to_bytes(sdp, sdkp->opt_xfer_blocks); + if (sdkp->opt_xfer_blocks == 0) + return false; + if (sdkp->opt_xfer_blocks > dev_max) { sd_first_printk(KERN_WARNING, sdkp, "Optimal transfer size %u logical blocks " \