It was reported that some devices report an OPTIMAL TRANSFER LENGTH of 0xFFFF blocks. That looks bogus, especially for a device with a 4096-byte physical block size.

Ignore OPTIMAL TRANSFER LENGTH if it is not a multiple of the device's reported physical block size.

To make the sanity checking conditionals more readable--and to facilitate printing warnings--relocate the checking to a helper function. No functional change aside from the printks.

Cc: stable@vger.kernel.org Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=199759 Reported-by: Christoph Anton Mitterer calestyo@scientia.net Signed-off-by: Martin K. Petersen martin.petersen@oracle.com

---

v2: - Added warnings as requested by hch - Moved the checks to a helper function

Before:

NAME ALIGNMENT MIN-IO OPT-IO PHY-SEC LOG-SEC ROTA SCHED RQ-SIZE RA WSAME sda 0 4096 33553920 4096 512 0 mq-deadline 256 128 32M

After:

NAME ALIGNMENT MIN-IO OPT-IO PHY-SEC LOG-SEC ROTA SCHED RQ-SIZE RA WSAME sda 0 4096 0 4096 512 0 mq-deadline 256 4096 32M --- drivers/scsi/sd.c | 59 +++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 50 insertions(+), 9 deletions(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index 9aa409b38765..5dfe37b08d3b 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -3048,6 +3048,55 @@ static void sd_read_security(struct scsi_disk *sdkp, unsigned char *buffer) sdkp->security = 1; }

+/* + * Determine the device's preferred I/O size for reads and writes + * unless the reported value is unreasonably small, large, not a + * multiple of the physical block size, or simply garbage. + */ +static bool sd_validate_opt_xfer_size(struct scsi_disk *sdkp, + unsigned int dev_max) +{ + struct scsi_device *sdp = sdkp->device; + unsigned int opt_xfer_bytes = + logical_to_bytes(sdp, sdkp->opt_xfer_blocks); + + if (sdkp->opt_xfer_blocks > dev_max) { + sd_first_printk(KERN_WARNING, sdkp, + "Optimal transfer size %u logical blocks " \ + "> dev_max (%u logical blocks)\n", + sdkp->opt_xfer_blocks, dev_max); + return false; + } + + if (sdkp->opt_xfer_blocks > SD_DEF_XFER_BLOCKS) { + sd_first_printk(KERN_WARNING, sdkp, + "Optimal transfer size %u logical blocks " \ + "> sd driver limit (%u logical blocks)\n", + sdkp->opt_xfer_blocks, SD_DEF_XFER_BLOCKS); + return false; + } + + if (opt_xfer_bytes < PAGE_SIZE) { + sd_first_printk(KERN_WARNING, sdkp, + "Optimal transfer size %u bytes < " \ + "PAGE_SIZE (%u bytes)\n", + opt_xfer_bytes, (unsigned int)PAGE_SIZE); + return false; + } + + if (opt_xfer_bytes & (sdkp->physical_block_size - 1)) { + sd_first_printk(KERN_WARNING, sdkp, + "Optimal transfer size %u bytes not a " \ + "multiple of physical block size (%u bytes)\n", + opt_xfer_bytes, sdkp->physical_block_size); + return false; + } + + sd_first_printk(KERN_INFO, sdkp, "Optimal transfer size %u bytes\n", + opt_xfer_bytes); + return true; +} + /** * sd_revalidate_disk - called the first time a new disk is seen, * performs disk spin up, read_capacity, etc. @@ -3117,15 +3166,7 @@ static int sd_revalidate_disk(struct gendisk *disk) dev_max = min_not_zero(dev_max, sdkp->max_xfer_blocks); q->limits.max_dev_sectors = logical_to_sectors(sdp, dev_max);

- /* - * Determine the device's preferred I/O size for reads and writes - * 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 && - logical_to_bytes(sdp, sdkp->opt_xfer_blocks) >= PAGE_SIZE) { + if (sd_validate_opt_xfer_size(sdkp, dev_max)) { q->limits.io_opt = logical_to_bytes(sdp, sdkp->opt_xfer_blocks); rw_max = logical_to_sectors(sdp, sdkp->opt_xfer_blocks); } else