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Revision 467d12f5c7842896d2de3ced74e4147ee29e97c8 authored by Christian Borntraeger on 21 February 2020, 04:04:03 UTC, committed by Linus Torvalds on 21 February 2020, 19:22:15 UTC 
include/uapi/linux/swab.h: fix userspace breakage, use __BITS_PER_LONG for swap
 
QEMU has a funny new build error message when I use the upstream kernel
headers:

      CC      block/file-posix.o
    In file included from /home/cborntra/REPOS/qemu/include/qemu/timer.h:4,
                     from /home/cborntra/REPOS/qemu/include/qemu/timed-average.h:29,
                     from /home/cborntra/REPOS/qemu/include/block/accounting.h:28,
                     from /home/cborntra/REPOS/qemu/include/block/block_int.h:27,
                     from /home/cborntra/REPOS/qemu/block/file-posix.c:30:
    /usr/include/linux/swab.h: In function `__swab':
    /home/cborntra/REPOS/qemu/include/qemu/bitops.h:20:34: error: "sizeof" is not defined, evaluates to 0 [-Werror=undef]
       20 | #define BITS_PER_LONG           (sizeof (unsigned long) * BITS_PER_BYTE)
          |                                  ^~~~~~
    /home/cborntra/REPOS/qemu/include/qemu/bitops.h:20:41: error: missing binary operator before token "("
       20 | #define BITS_PER_LONG           (sizeof (unsigned long) * BITS_PER_BYTE)
          |                                         ^
    cc1: all warnings being treated as errors
    make: *** [/home/cborntra/REPOS/qemu/rules.mak:69: block/file-posix.o] Error 1
    rm tests/qemu-iotests/socket_scm_helper.o

This was triggered by commit d5767057c9a ("uapi: rename ext2_swab() to
swab() and share globally in swab.h").  That patch is doing

  #include <asm/bitsperlong.h>

but it uses BITS_PER_LONG.

The kernel file asm/bitsperlong.h provide only __BITS_PER_LONG.

Let us use the __ variant in swap.h

Link: http://lkml.kernel.org/r/20200213142147.17604-1-borntraeger@de.ibm.com
Fixes: d5767057c9a ("uapi: rename ext2_swab() to swab() and share globally in swab.h")
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Yury Norov <yury.norov@gmail.com>
Cc: Allison Randal <allison@lohutok.net>
Cc: Joe Perches <joe@perches.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: William Breathitt Gray <vilhelm.gray@gmail.com>
Cc: Torsten Hilbrich <torsten.hilbrich@secunet.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent edf28f4
Raw File
gfp-translate 
#!/bin/bash
# SPDX-License-Identifier: GPL-2.0-only
# Translate the bits making up a GFP mask
# (c) 2009, Mel Gorman <mel@csn.ul.ie>
SOURCE=
GFPMASK=none

# Helper function to report failures and exit
die() {
	echo ERROR: $@
	if [ "$TMPFILE" != "" ]; then
		rm -f $TMPFILE
	fi
	exit -1
}

usage() {
	echo "usage: gfp-translate [-h] [ --source DIRECTORY ] gfpmask"
	exit 0
}

# Parse command-line arguments
while [ $# -gt 0 ]; do
	case $1 in
		--source)
			SOURCE=$2
			shift 2
			;;
		-h)
			usage
			;;
		--help)
			usage
			;;
		*)
			GFPMASK=$1
			shift
			;;
	esac
done

# Guess the kernel source directory if it's not set. Preference is in order of
# o current directory
# o /usr/src/linux
if [ "$SOURCE" = "" ]; then
	if [ -r "/usr/src/linux/Makefile" ]; then
		SOURCE=/usr/src/linux
	fi
	if [ -r "`pwd`/Makefile" ]; then
		SOURCE=`pwd`
	fi
fi

# Confirm that a source directory exists
if [ ! -r "$SOURCE/Makefile" ]; then
	die "Could not locate kernel source directory or it is invalid"
fi

# Confirm that a GFP mask has been specified
if [ "$GFPMASK" = "none" ]; then
	usage
fi

# Extract GFP flags from the kernel source
TMPFILE=`mktemp -t gfptranslate-XXXXXX` || exit 1
grep -q ___GFP $SOURCE/include/linux/gfp.h
if [ $? -eq 0 ]; then
	grep "^#define ___GFP" $SOURCE/include/linux/gfp.h | sed -e 's/u$//' | grep -v GFP_BITS > $TMPFILE
else
	grep "^#define __GFP" $SOURCE/include/linux/gfp.h | sed -e 's/(__force gfp_t)//' | sed -e 's/u)/)/' | grep -v GFP_BITS | sed -e 's/)\//) \//' > $TMPFILE
fi

# Parse the flags
IFS="
"
echo Source: $SOURCE
echo Parsing: $GFPMASK
for LINE in `cat $TMPFILE`; do
	MASK=`echo $LINE | awk '{print $3}'`
	if [ $(($GFPMASK&$MASK)) -ne 0 ]; then
		echo $LINE
	fi
done

rm -f $TMPFILE
exit 0
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