On 22/07/2025 11:26, John Garry wrote:
The merging/splitting code and other queue limits checking depends on the
physical block size being a power-of-2, so enforce it.
JFYI, I have done an audit of all drivers setting physical_block_size
queue limit. I have doubts on a couple, but it seems that NVMe may be
the only driver which does not guarantee a power-of-2 physical block
size - maybe I even am wrong about that.
drivers/block/brd.c - uses PAGE_SIZE, so ok
drivers/block/drbd/drbd_main.c - uses bdev_physical_block_size(), so ok
drivers/block/loop.c - uses same size as LBS (which must be a
power-of-2), so ok
drivers/block/mtip32xx/mtip32xx.c - uses 4096, so ok
drivers/block/n64cart.c - uses 4096, so ok
drivers/block/nbd.c - uses same size as LBS (which must be a
power-of-2), so ok
drivers/block/null_blk/main.c - uses same size as LBS (which must be a
power-of-2), so ok
drivers/block/rnbd/rnbd-clt.c - drivers/block/rnbd/rnbd-srv.c - uses
bdev_physical_block_size() to fill in
rnbd_msg_open_rsp.physical_block_size, and rnbd-clt.c fills in
queue_limits.physical_block_size from
rnbd_msg_open_rsp.physical_block_size, so looks ok
drivers/block/sunvdc.c not sure on this one. For v1.2 spec we have
vio_disk_attr_info.phys_block_size, but I cannot
find a spec detailing it.
https://oss.oracle.com/sparcdocs/hypervisor-api-3.0draft7.pdf has
earlier specs. FWIW, no rules on power-of-2 not mentioned for
vdisk_block_size in that spec, so unlikely to have rules for physical
block size. Default pbs is VDC_DEFAULT_BLK_SIZE = 512, and other sizes
in driver are all power-of-2, so likely phys_block_size
will be a power-of-2 always
drivers/block/ublk_drv.c - uses 1 << p->physical_bs_shift, so ok
drivers/block/virtio_blk.c - not sure, as we use
zone_write_granularity and I don't know if that must be a power-of-2,
but from sd_zbc_read_zones() we use physical_block_size, so prob ok
drivers/block/zloop.c - uses same size as LBS (which must be a
power-of-2), so ok
drivers/block/zram/zram_drv.c - uses PAGE_SIZE, so ok
drivers/md/bcache/super.c - uses same size as LBS (which must be a
power-of-2), so ok
drivers/md/dm-crypt.c - uses same size as LBS (which must be a
power-of-2), so ok
drivers/md/dm-ebs-target.c - ebs_ctr() -> __ebs_check_bs() ensures a
power-of-2, so ok
drivers/md/dm-integrity.c - uses same size as LBS (which must be a
power-of-2), so ok
drivers/md/dm-log-writes.c - uses bdev_physical_block_size(), so ok
drivers/md/dm-vdo/dm-vdo-target.c - VDO_BLOCK_SIZE = 4096, so ok
drivers/md/dm-verity-target.c - uses 1 << v->data_dev_block_bits, so ok
drivers/md/dm-writecache.c - writecache_ctr() line 2376 ensure
blocksize is a power-of-2, so ok
drivers/md/dm-zoned-target.c - uses same size as LBS (which must be a
power-of-2), so ok
drivers/nvdimm/pmem.c - uses PAGE_SIZE, so ok
drivers/nvme/host/core.c - may not be ok, so pbs comes from npwg and
spec does not mandate this is a power-of-2
drivers/scsi/sd.c - uses (1 << (buffer[13] & 0xf)) * sector_size in
sdkp->physical_block_size, so ok
drivers/scsi/sd_zbc.c - uses sdkp->physical_block_size, so ok
drivers/target/target_core_iblock.c - uses bdev_physical_block_size(), so ok
Signed-off-by: John Garry <john.g.garry@xxxxxxxxxx>
---
block/blk-settings.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/block/blk-settings.c b/block/blk-settings.c
index fa53a330f9b9..5ae0a253e43f 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -274,6 +274,10 @@ int blk_validate_limits(struct queue_limits *lim)
}
if (lim->physical_block_size < lim->logical_block_size)
lim->physical_block_size = lim->logical_block_size;
+ else if (!is_power_of_2(lim->physical_block_size)) {
+ pr_warn("Invalid physical block size (%d)\n", lim->physical_block_size);
+ return -EINVAL;
+ }
/*
* The minimum I/O size defaults to the physical block size unless
