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 -- 2.5.0 -- 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
