On Wed, 2015-12-16 at 17:53 -0500, Martin K. Petersen wrote: > Eryu Guan reported that loading scsi_debug would fail. This turned out > to be caused by scsi_debug reporting an optimal I/O size of 32KB which > is smaller than the 64KB page size on the PowerPC system in question. > > Add a check to ensure that we only use the device-reported OPTIMAL > TRANSFER LENGTH if it is bigger than or equal to the page cache size. > > Reported-by: Eryu Guan <guaneryu@xxxxxxxxx> > Reported-by: Ming Lei <tom.leiming@xxxxxxxxx> > Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx> > --- > drivers/scsi/sd.c | 9 ++++++--- > 1 file changed, 6 insertions(+), 3 deletions(-) > > diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c > index 3d22fc3e3c1a..4e08d1cd704d 100644 > --- a/drivers/scsi/sd.c > +++ b/drivers/scsi/sd.c > @@ -2885,10 +2885,13 @@ static int sd_revalidate_disk(struct gendisk *disk) > > /* > * Use the device's preferred I/O size for reads and writes > - * unless the reported value is unreasonably large (or garbage). > + * unless the reported value is unreasonably small, large, or > + * garbage. > */ > - if (sdkp->opt_xfer_blocks && sdkp->opt_xfer_blocks <= dev_max && > - sdkp->opt_xfer_blocks <= SD_DEF_XFER_BLOCKS) > + if (sdkp->opt_xfer_blocks && > + sdkp->opt_xfer_blocks <= dev_max && > + sdkp->opt_xfer_blocks <= SD_DEF_XFER_BLOCKS && > + sdkp->opt_xfer_blocks * sdp->sector_size >= PAGE_CACHE_SIZE) > rw_max = q->limits.io_opt = > logical_to_sectors(sdp, sdkp->opt_xfer_blocks); > else Reviewed-by: Ewan D. Milne <emilne@xxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
