virtio_blk: set the zone write granularitygrafted

virtblk_read_zoned_limits() reads the write granularity that the device
reports in virtio_blk_zoned_characteristics and assigns it to the
physical block size and to io_min, but never to the limit that is named
after it. queue_limits.zone_write_granularity is left at zero, so
blk_validate_zoned_limits() raises it to the logical block size:

	if (lim->zone_write_granularity < lim->logical_block_size)
		lim->zone_write_granularity = lim->logical_block_size;

A device that reports a granularity coarser than its logical block size,
which is what the field exists to express, therefore has it silently
reduced. A 512e host managed disk passed through to a guest reports a
logical block size of 512 and a write granularity of 4096, and the guest
ends up with a zone write granularity of 512.

bio_split_alignment() returns lim->zone_write_granularity if it is non-zero
and bio_split_io_at() may split a bio with as per bio_split_alignment().
This can real to the write getting rejected by the host drive, as the write
is not aligned to the physical block size.

zonefs also takes its block size from bdev_zone_write_granularity(), so it
would incorrectly use 512 on a disk that requires 4096.

sd_zbc_read_zones() sets the limit from the physical block size for the
same reason. NVMe ZNS and null_blk leave it unset, but the fallback
gives the right answer for them, as their write granularity is the
logical block size. virtio carries a separate value that may exceed it.

Set the zone write granularity from the value that the device reports.

Fixes: 95bfec41bd3d ("virtio-blk: add support for zoned block devices")
Signed-off-by: Niklas Cassel <cassel@kernel.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Link: https://patch.msgid.link/20260918140641.2031075-2-cassel@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

7 files changed, 156 insertions, 0 deletions

diff --git a/scripts/dummy-tools/dummy-plugin-dir/include/plugin-version.h b/scripts/dummy-tools/dummy-plugin-dir/include/plugin-version.h
new file mode 100644
index 000000000..e69de29bb
--- /dev/null
+++ b/scripts/dummy-tools/dummy-plugin-dir/include/plugin-version.h
diff --git a/scripts/dummy-tools/gcc b/scripts/dummy-tools/gcc
new file mode 100755
index 000000000..e6c41427c
--- /dev/null
+++ b/scripts/dummy-tools/gcc
@@ -0,0 +1,116 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Staring v4.18, Kconfig evaluates compiler capabilities, and hides CONFIG
+# options your compiler does not support. This works well if you configure and
+# build the kernel on the same host machine.
+#
+# It is inconvenient if you prepare the .config that is carried to a different
+# build environment (typically this happens when you package the kernel for
+# distros) because using a different compiler potentially produces different
+# CONFIG options than the real build environment. So, you probably want to make
+# as many options visible as possible. In other words, you need to create a
+# super-set of CONFIG options that cover any build environment. If some of the
+# CONFIG options turned out to be unsupported on the build machine, they are
+# automatically disabled by the nature of Kconfig.
+#
+# However, it is not feasible to get a full-featured compiler for every arch.
+# Hence these dummy toolchains to make all compiler tests pass.
+#
+# Usage:
+#
+# From the top directory of the source tree, run
+#
+#   $ make CROSS_COMPILE=scripts/dummy-tools/ oldconfig
+#
+# Most of compiler features are tested by cc-option, which simply checks the
+# exit code of $(CC). This script does nothing and just exits with 0 in most
+# cases. So, $(cc-option, ...) is evaluated as 'y'.
+#
+# This scripts caters to more checks; handle --version and pre-process __GNUC__
+# etc. to pretend to be GCC, and also do right things to satisfy some scripts.
+
+# Check if the first parameter appears in the rest. Succeeds if found.
+# This helper is useful if a particular option was passed to this script.
+# Typically used like this:
+#   arg_contain <word-you-are-searching-for> "$@"
+arg_contain ()
+{
+	search="$1"
+	shift
+
+	while [ $# -gt 0 ]
+	do
+		if [ "$search" = "$1" ]; then
+			return 0
+		fi
+		shift
+	done
+
+	return 1
+}
+
+# To set CONFIG_CC_IS_GCC=y
+if arg_contain --version "$@"; then
+	echo "gcc (scripts/dummy-tools/gcc)"
+	exit 0
+fi
+
+if arg_contain -E "$@"; then
+	# For scripts/cc-version.sh; This emulates GCC 20.0.0
+	if arg_contain - "$@"; then
+		sed -n '/^GCC/{s/__GNUC__/20/; s/__GNUC_MINOR__/0/; s/__GNUC_PATCHLEVEL__/0/; p;}; s/__LONG_DOUBLE_128__/1/ p'
+		exit 0
+	else
+		echo "no input files" >&2
+		exit 1
+	fi
+fi
+
+# To set CONFIG_AS_IS_GNU
+if arg_contain -Wa,--version "$@"; then
+	echo "GNU assembler (scripts/dummy-tools) 2.50"
+	exit 0
+fi
+
+if arg_contain -S "$@"; then
+	# For scripts/gcc-x86-*-has-stack-protector.sh
+	if arg_contain -fstack-protector "$@"; then
+		if arg_contain -mstack-protector-guard-reg=fs "$@"; then
+			echo "%fs"
+		else
+			echo "%gs"
+		fi
+		exit 0
+	fi
+
+	# For arch/powerpc/tools/gcc-check-mprofile-kernel.sh
+	if arg_contain -m64 "$@" && arg_contain -mprofile-kernel "$@"; then
+		if ! test -t 0 && ! grep -q notrace; then
+			echo "_mcount"
+		fi
+		exit 0
+	fi
+
+	# For arch/powerpc/tools/gcc-check-fpatchable-function-entry.sh
+	if arg_contain -m64 "$@" && arg_contain -fpatchable-function-entry=2 "$@"; then
+		echo "func:"
+		echo ".section __patchable_function_entries"
+		echo ".localentry"
+		echo "  nop"
+		echo "  nop"
+		exit 0
+	fi
+fi
+
+# To set GCC_PLUGINS
+if arg_contain -print-file-name=plugin "$@"; then
+	# Use $0 to find the in-tree dummy directory
+	echo "$(dirname "$(readlink -f "$0")")/dummy-plugin-dir"
+	exit 0
+fi
+
+# inverted return value
+if arg_contain -D__SIZEOF_INT128__=0 "$@"; then
+	exit 1
+fi
diff --git a/scripts/dummy-tools/ld b/scripts/dummy-tools/ld
new file mode 100755
index 000000000..f68233050
--- /dev/null
+++ b/scripts/dummy-tools/ld
@@ -0,0 +1,30 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0-only
+
+# Dummy script that always succeeds.
+
+# Check if the first parameter appears in the rest. Succeeds if found.
+# This helper is useful if a particular option was passed to this script.
+# Typically used like this:
+#   arg_contain <word-you-are-searching-for> "$@"
+arg_contain ()
+{
+	search="$1"
+	shift
+
+	while [ $# -gt 0 ]
+	do
+		if [ "$search" = "$1" ]; then
+			return 0
+		fi
+		shift
+	done
+
+	return 1
+}
+
+if arg_contain --version "$@" || arg_contain -v "$@"; then
+	progname=$(basename $0)
+	echo "GNU $progname (scripts/dummy-tools/$progname) 2.50"
+	exit 0
+fi
diff --git a/scripts/dummy-tools/nm b/scripts/dummy-tools/nm
new file mode 120000
index 000000000..c0648b38d
--- /dev/null
+++ b/scripts/dummy-tools/nm
@@ -0,0 +1 @@
+ld
\ No newline at end of file
diff --git a/scripts/dummy-tools/objcopy b/scripts/dummy-tools/objcopy
new file mode 120000
index 000000000..c0648b38d
--- /dev/null
+++ b/scripts/dummy-tools/objcopy
@@ -0,0 +1 @@
+ld
\ No newline at end of file
diff --git a/scripts/dummy-tools/pahole b/scripts/dummy-tools/pahole
new file mode 100755
index 000000000..53501a36f
--- /dev/null
+++ b/scripts/dummy-tools/pahole
@@ -0,0 +1,4 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0-only
+
+echo v99.99
diff --git a/scripts/dummy-tools/python3 b/scripts/dummy-tools/python3
new file mode 100755
index 000000000..24c558486
--- /dev/null
+++ b/scripts/dummy-tools/python3
@@ -0,0 +1,4 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0-only
+
+true