Commit 0b4a7092 authored Jun 06, 2019 by Michael S. Tsirkin

vhost: fix clang build warning

Clang warns:

  drivers/vhost/vhost.c:2085:5: warning: macro expansion producing
  'defined' has undefined behavior [-Wexpansion-to-defined]
  #if VHOST_ARCH_CAN_ACCEL_UACCESS
      ^
  drivers/vhost/vhost.h:98:38: note: expanded from macro
  'VHOST_ARCH_CAN_ACCEL_UACCESS'
  #define VHOST_ARCH_CAN_ACCEL_UACCESS defined(CONFIG_MMU_NOTIFIER) && \
                                       ^

It's being pedantic for the sake of portability, but the fix is easy
enough.

Rework the definition of VHOST_ARCH_CAN_ACCEL_UACCESS to expand to a constant.

Fixes: 7f466032 ("vhost: access vq metadata through kernel virtual address")
Link: https://github.com/ClangBuiltLinux/linux/issues/508


Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>

parent 7f466032

drivers/vhost/vhost.h

+5 −2

Original line number	Diff line number	Diff line
		@@ -95,8 +95,11 @@ struct vhost_uaddr {
		bool write;
		};

		#define VHOST_ARCH_CAN_ACCEL_UACCESS defined(CONFIG_MMU_NOTIFIER) && \
		ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE == 0
		#if defined(CONFIG_MMU_NOTIFIER) && ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE == 0
		#define VHOST_ARCH_CAN_ACCEL_UACCESS 1
		#else
		#define VHOST_ARCH_CAN_ACCEL_UACCESS 0
		#endif

		/* The virtqueue structure describes a queue attached to a device. */
		struct vhost_virtqueue {

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