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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
blk-mq-virtio.c 
// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2016 Christoph Hellwig.
 */
#include <linux/device.h>
#include <linux/blk-mq.h>
#include <linux/blk-mq-virtio.h>
#include <linux/virtio_config.h>
#include <linux/module.h>
#include "blk-mq.h"

/**
 * blk_mq_virtio_map_queues - provide a default queue mapping for virtio device
 * @qmap:	CPU to hardware queue map.
 * @vdev:	virtio device to provide a mapping for.
 * @first_vec:	first interrupt vectors to use for queues (usually 0)
 *
 * This function assumes the virtio device @vdev has at least as many available
 * interrupt vetors as @set has queues.  It will then queuery the vector
 * corresponding to each queue for it's affinity mask and built queue mapping
 * that maps a queue to the CPUs that have irq affinity for the corresponding
 * vector.
 */
int blk_mq_virtio_map_queues(struct blk_mq_queue_map *qmap,
		struct virtio_device *vdev, int first_vec)
{
	const struct cpumask *mask;
	unsigned int queue, cpu;

	if (!vdev->config->get_vq_affinity)
		goto fallback;

	for (queue = 0; queue < qmap->nr_queues; queue++) {
		mask = vdev->config->get_vq_affinity(vdev, first_vec + queue);
		if (!mask)
			goto fallback;

		for_each_cpu(cpu, mask)
			qmap->mq_map[cpu] = qmap->queue_offset + queue;
	}

	return 0;
fallback:
	return blk_mq_map_queues(qmap);
}
EXPORT_SYMBOL_GPL(blk_mq_virtio_map_queues);
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