iopoll: Introduce read_poll_timeout_atomic macro (57a29df3) · Commits · 戴 / test

include/linux/iopoll.h

+43 −19

Original line number	Diff line number	Diff line
		@@ -57,6 +57,48 @@
		(cond) ? 0 : -ETIMEDOUT; \
		})

		/**
		* read_poll_timeout_atomic - Periodically poll an address until a condition is
		* met or a timeout occurs
		* @op: accessor function (takes @addr as its only argument)
		* @addr: Address to poll
		* @val: Variable to read the value into
		* @cond: Break condition (usually involving @val)
		* @delay_us: Time to udelay between reads in us (0 tight-loops). Should
		* be less than ~10us since udelay is used (see
		* Documentation/timers/timers-howto.rst).
		* @timeout_us: Timeout in us, 0 means never timeout
		* @delay_before_read: if it is true, delay @delay_us before read.
		*
		* Returns 0 on success and -ETIMEDOUT upon a timeout. In either
		* case, the last read value at @args is stored in @val.
		*
		* When available, you'll probably want to use one of the specialized
		* macros defined below rather than this macro directly.
		*/
		#define read_poll_timeout_atomic(op, val, cond, delay_us, timeout_us, \
		delay_before_read, args...) \
		({ \
		u64 __timeout_us = (timeout_us); \
		unsigned long __delay_us = (delay_us); \
		ktime_t __timeout = ktime_add_us(ktime_get(), __timeout_us); \
		if (delay_before_read && __delay_us) \
		udelay(__delay_us); \
		for (;;) { \
		(val) = op(args); \
		if (cond) \
		break; \
		if (__timeout_us && \
		ktime_compare(ktime_get(), __timeout) > 0) { \
		(val) = op(args); \
		break; \
		} \
		if (__delay_us) \
		udelay(__delay_us); \
		} \
		(cond) ? 0 : -ETIMEDOUT; \
		})

		/**
		* readx_poll_timeout - Periodically poll an address until a condition is met or a timeout occurs
		* @op: accessor function (takes @addr as its only argument)
		@@ -96,25 +138,7 @@
		* macros defined below rather than this macro directly.
		*/
		#define readx_poll_timeout_atomic(op, addr, val, cond, delay_us, timeout_us) \
		({ \
		u64 __timeout_us = (timeout_us); \
		unsigned long __delay_us = (delay_us); \
		ktime_t __timeout = ktime_add_us(ktime_get(), __timeout_us); \
		for (;;) { \
		(val) = op(addr); \
		if (cond) \
		break; \
		if (__timeout_us && \
		ktime_compare(ktime_get(), __timeout) > 0) { \
		(val) = op(addr); \
		break; \
		} \
		if (__delay_us) \
		udelay(__delay_us); \
		} \
		(cond) ? 0 : -ETIMEDOUT; \
		})

		read_poll_timeout_atomic(op, val, cond, delay_us, timeout_us, false, addr)

		#define readb_poll_timeout(addr, val, cond, delay_us, timeout_us) \
		readx_poll_timeout(readb, addr, val, cond, delay_us, timeout_us)

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