virtio_config: rewrite using _Generic (a5b90f2d) · Commits · 戴 / test

include/linux/virtio_config.h

+76 −85

Original line number	Diff line number	Diff line
		@@ -288,112 +288,103 @@ static inline __virtio64 cpu_to_virtio64(struct virtio_device *vdev, u64 val)
		return __cpu_to_virtio64(virtio_is_little_endian(vdev), val);
		}

		#define virtio_to_cpu(vdev, x) \
		_Generic((x), \
		__u8: (x), \
		__virtio16: virtio16_to_cpu((vdev), (x)), \
		__virtio32: virtio32_to_cpu((vdev), (x)), \
		__virtio64: virtio64_to_cpu((vdev), (x)), \
		/*
		* Only the checker differentiates between __virtioXX and __uXX types. But we
		* try to share as much code as we can with the regular GCC build.
		*/
		#if !defined(CONFIG_CC_IS_GCC) && !defined(__CHECKER__)

		/* Not a checker - we can keep things simple */
		#define __virtio_native_typeof(x) typeof(x)

		#else

		* Why define a default? checker can distinguish between
		* e.g. __u16, __le16 and __virtio16, but GCC can't so
		* attempts to define variants for both look like a duplicate
		* variant to it.
		*/ \
		default: _Generic((x), \
		__u8: (x), \
		__le16: virtio16_to_cpu((vdev), (__force __virtio16)(x)), \
		__le32: virtio32_to_cpu((vdev), (__force __virtio32)(x)), \
		__le64: virtio64_to_cpu((vdev), (__force __virtio64)(x)), \
		default: _Generic((x), \
		__u8: (x), \
		__u16: virtio16_to_cpu((vdev), (__force __virtio16)(x)), \
		__u32: virtio32_to_cpu((vdev), (__force __virtio32)(x)), \
		__u64: virtio64_to_cpu((vdev), (__force __virtio64)(x)) \
		) \
		) \
		)

		#define cpu_to_virtio(vdev, x, m) \
		_Generic((m), \
		__u8: (x), \
		__virtio16: cpu_to_virtio16((vdev), (x)), \
		__virtio32: cpu_to_virtio32((vdev), (x)), \
		__virtio64: cpu_to_virtio64((vdev), (x)), \
		/*
		* We build this out of a couple of helper macros in a vain attempt to
		* help you keep your lunch down while reading it.
		*/
		#define __virtio_pick_value(x, type, then, otherwise) \
		__builtin_choose_expr(__same_type(x, type), then, otherwise)

		#define __virtio_pick_type(x, type, then, otherwise) \
		__virtio_pick_value(x, type, (then)0, otherwise)

		#define __virtio_pick_endian(x, x16, x32, x64, otherwise) \
		__virtio_pick_type(x, x16, __u16, \
		__virtio_pick_type(x, x32, __u32, \
		__virtio_pick_type(x, x64, __u64, \
		otherwise)))

		#define __virtio_native_typeof(x) typeof( \
		__virtio_pick_type(x, __u8, __u8, \
		__virtio_pick_endian(x, __virtio16, __virtio32, __virtio64, \
		__virtio_pick_endian(x, __le16, __le32, __le64, \
		/* No other type allowed */ \
		(void)0))))

		#endif
		* Why define a default? checker can distinguish between
		* e.g. __u16, __le16 and __virtio16, but GCC can't so
		* attempts to define variants for both look like a duplicate
		* variant to it.
		*/ \
		default: _Generic((m), \
		__u8: (x), \
		__le16: (__force __le16)cpu_to_virtio16((vdev), (x)), \
		__le32: (__force __le32)cpu_to_virtio32((vdev), (x)), \
		__le64: (__force __le64)cpu_to_virtio64((vdev), (x)), \
		default: _Generic((m), \
		__u8: (x), \
		__u16: (__force __u16)cpu_to_virtio16((vdev), (x)), \
		__u32: (__force __u32)cpu_to_virtio32((vdev), (x)), \
		__u64: (__force __u64)cpu_to_virtio64((vdev), (x)) \
		) \
		) \
		)

		#define __virtio_native_type(structname, member) \
		__virtio_native_typeof(((structname*)0)->member)

		#define __virtio_typecheck(structname, member, val) \
		/* Must match the member's type, and be integer */ \
		typecheck(__virtio_native_type(structname, member), (val))

		typeof(virtio_to_cpu(NULL, ((structname*)0)->member))

		/* Config space accessors. */
		#define virtio_cread(vdev, structname, member, ptr) \
		do { \
		typeof(((structname*)0)->member) virtio_cread_v; \
		\
		might_sleep(); \
		/* Must match the member's type, and be integer */ \
		if (!__virtio_typecheck(structname, member, *(ptr))) \
		(*ptr) = 1; \
		/* Sanity check: must match the member's type */ \
		typecheck(typeof(virtio_to_cpu((vdev), virtio_cread_v)), *(ptr)); \
		\
		switch (sizeof(*ptr)) { \
		switch (sizeof(virtio_cread_v)) { \
		case 1: \
		*(ptr) = virtio_cread8(vdev, \
		offsetof(structname, member)); \
		break; \
		case 2: \
		*(ptr) = virtio_cread16(vdev, \
		offsetof(structname, member)); \
		break; \
		case 4: \
		*(ptr) = virtio_cread32(vdev, \
		offsetof(structname, member)); \
		break; \
		case 8: \
		*(ptr) = virtio_cread64(vdev, \
		offsetof(structname, member)); \
		vdev->config->get((vdev), \
		offsetof(structname, member), \
		&virtio_cread_v, \
		sizeof(virtio_cread_v)); \
		break; \
		default: \
		BUG(); \
		__virtio_cread_many((vdev), \
		offsetof(structname, member), \
		&virtio_cread_v, \
		1, \
		sizeof(virtio_cread_v)); \
		break; \
		} \
		*(ptr) = virtio_to_cpu(vdev, virtio_cread_v); \
		} while(0)

		/* Config space accessors. */
		#define virtio_cwrite(vdev, structname, member, ptr) \
		do { \
		typeof(((structname*)0)->member) virtio_cwrite_v = \
		cpu_to_virtio(vdev, (ptr), ((structname)0)->member); \
		\
		might_sleep(); \
		/* Must match the member's type, and be integer */ \
		if (!__virtio_typecheck(structname, member, *(ptr))) \
		BUG_ON((*ptr) == 1); \
		/* Sanity check: must match the member's type */ \
		typecheck(typeof(virtio_to_cpu((vdev), virtio_cwrite_v)), *(ptr)); \
		\
		switch (sizeof(*ptr)) { \
		case 1: \
		virtio_cwrite8(vdev, \
		offsetof(structname, member), \
		*(ptr)); \
		break; \
		case 2: \
		virtio_cwrite16(vdev, \
		offsetof(structname, member), \
		*(ptr)); \
		break; \
		case 4: \
		virtio_cwrite32(vdev, \
		offsetof(structname, member), \
		*(ptr)); \
		break; \
		case 8: \
		virtio_cwrite64(vdev, \
		offsetof(structname, member), \
		*(ptr)); \
		break; \
		default: \
		BUG(); \
		} \
		vdev->config->set((vdev), offsetof(structname, member), \
		&virtio_cwrite_v, \
		sizeof(virtio_cwrite_v)); \
		} while(0)

		/* Read @count fields, @bytes each. */

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