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scsi: sd: Optimal I/O size should be a multiple of physical block size

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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>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Martin K. Petersen 2019-02-12 16:21:05 -05:00
parent d1420f2c0f
commit a83da8a450
1 changed files with 50 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

59
drivers/scsi/sd.c
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@ -3061,6 +3061,55 @@ 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.
@ -3130,15 +3179,7 @@ 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