Files
linux-cryptodev-2.6/include/linux/iopoll.h
Ville Syrjälä 563e5eca4e iopoll: Avoid evaluating 'cond' twice in poll_timeout_us()
Currently poll_timeout_us() evaluates 'cond' twice at the end
of the success case. This not desirable in case 'cond' itself
is expensive.

Avoid the double evaluation by tracking the return value in
a variable. Need to use a triple undescore '___ret' name to
avoid a conflict with an existing double undescore '__ret'
variable in the regmap code.

Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Dibin Moolakadan Subrahmanian <dibin.moolakadan.subrahmanian@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: David Laight <david.laight.linux@gmail.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Matt Wagantall <mattw@codeaurora.org>
Cc: Dejin Zheng <zhengdejin5@gmail.com>
Cc: intel-gfx@lists.freedesktop.org
Cc: intel-xe@lists.freedesktop.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Acked-by: Simona Vetter <simona.vetter@ffwll.ch>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://lore.kernel.org/r/20250826121859.15497-2-ville.syrjala@linux.intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
2025-08-28 12:17:32 +03:00

266 lines
10 KiB
C

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (c) 2012-2014 The Linux Foundation. All rights reserved.
*/
#ifndef _LINUX_IOPOLL_H
#define _LINUX_IOPOLL_H
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/ktime.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/io.h>
/**
* poll_timeout_us - Periodically poll and perform an operation until
* a condition is met or a timeout occurs
*
* @op: Operation
* @cond: Break condition
* @sleep_us: Maximum time to sleep between operations in us (0 tight-loops).
* Please read usleep_range() function description for details and
* limitations.
* @timeout_us: Timeout in us, 0 means never timeout
* @sleep_before_op: if it is true, sleep @sleep_us before operation.
*
* When available, you'll probably want to use one of the specialized
* macros defined below rather than this macro directly.
*
* Returns: 0 on success and -ETIMEDOUT upon a timeout. Must not
* be called from atomic context if sleep_us or timeout_us are used.
*/
#define poll_timeout_us(op, cond, sleep_us, timeout_us, sleep_before_op) \
({ \
u64 __timeout_us = (timeout_us); \
unsigned long __sleep_us = (sleep_us); \
ktime_t __timeout = ktime_add_us(ktime_get(), __timeout_us); \
int ___ret; \
might_sleep_if((__sleep_us) != 0); \
if ((sleep_before_op) && __sleep_us) \
usleep_range((__sleep_us >> 2) + 1, __sleep_us); \
for (;;) { \
op; \
if (cond) { \
___ret = 0; \
break; \
} \
if (__timeout_us && \
ktime_compare(ktime_get(), __timeout) > 0) { \
op; \
if (cond) \
___ret = 0; \
else \
___ret = -ETIMEDOUT; \
break; \
} \
if (__sleep_us) \
usleep_range((__sleep_us >> 2) + 1, __sleep_us); \
cpu_relax(); \
} \
___ret; \
})
/**
* poll_timeout_us_atomic - Periodically poll and perform an operation until
* a condition is met or a timeout occurs
*
* @op: Operation
* @cond: Break condition
* @delay_us: Time to udelay between operations in us (0 tight-loops).
* Please read udelay() function description for details and
* limitations.
* @timeout_us: Timeout in us, 0 means never timeout
* @delay_before_op: if it is true, delay @delay_us before operation.
*
* This macro does not rely on timekeeping. Hence it is safe to call even when
* timekeeping is suspended, at the expense of an underestimation of wall clock
* time, which is rather minimal with a non-zero delay_us.
*
* When available, you'll probably want to use one of the specialized
* macros defined below rather than this macro directly.
*
* Returns: 0 on success and -ETIMEDOUT upon a timeout.
*/
#define poll_timeout_us_atomic(op, cond, delay_us, timeout_us, \
delay_before_op) \
({ \
u64 __timeout_us = (timeout_us); \
s64 __left_ns = __timeout_us * NSEC_PER_USEC; \
unsigned long __delay_us = (delay_us); \
u64 __delay_ns = __delay_us * NSEC_PER_USEC; \
int ___ret; \
if ((delay_before_op) && __delay_us) { \
udelay(__delay_us); \
if (__timeout_us) \
__left_ns -= __delay_ns; \
} \
for (;;) { \
op; \
if (cond) { \
___ret = 0; \
break; \
} \
if (__timeout_us && __left_ns < 0) { \
op; \
if (cond) \
___ret = 0; \
else \
___ret = -ETIMEDOUT; \
break; \
} \
if (__delay_us) { \
udelay(__delay_us); \
if (__timeout_us) \
__left_ns -= __delay_ns; \
} \
cpu_relax(); \
if (__timeout_us) \
__left_ns--; \
} \
___ret; \
})
/**
* read_poll_timeout - Periodically poll an address until a condition is
* met or a timeout occurs
* @op: accessor function (takes @args as its arguments)
* @val: Variable to read the value into
* @cond: Break condition (usually involving @val)
* @sleep_us: Maximum time to sleep between reads in us (0 tight-loops). Please
* read usleep_range() function description for details and
* limitations.
* @timeout_us: Timeout in us, 0 means never timeout
* @sleep_before_read: if it is true, sleep @sleep_us before read.
* @args: arguments for @op poll
*
* When available, you'll probably want to use one of the specialized
* macros defined below rather than this macro directly.
*
* Returns: 0 on success and -ETIMEDOUT upon a timeout. In either
* case, the last read value at @args is stored in @val. Must not
* be called from atomic context if sleep_us or timeout_us are used.
*/
#define read_poll_timeout(op, val, cond, sleep_us, timeout_us, \
sleep_before_read, args...) \
poll_timeout_us((val) = op(args), cond, sleep_us, timeout_us, sleep_before_read)
/**
* read_poll_timeout_atomic - Periodically poll an address until a condition is
* met or a timeout occurs
* @op: accessor function (takes @args as its arguments)
* @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). Please
* read udelay() function description for details and
* limitations.
* @timeout_us: Timeout in us, 0 means never timeout
* @delay_before_read: if it is true, delay @delay_us before read.
* @args: arguments for @op poll
*
* This macro does not rely on timekeeping. Hence it is safe to call even when
* timekeeping is suspended, at the expense of an underestimation of wall clock
* time, which is rather minimal with a non-zero delay_us.
*
* When available, you'll probably want to use one of the specialized
* macros defined below rather than this macro directly.
*
* Returns: 0 on success and -ETIMEDOUT upon a timeout. In either
* case, the last read value at @args is stored in @val.
*/
#define read_poll_timeout_atomic(op, val, cond, sleep_us, timeout_us, \
sleep_before_read, args...) \
poll_timeout_us_atomic((val) = op(args), cond, sleep_us, timeout_us, sleep_before_read)
/**
* 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)
* @addr: Address to poll
* @val: Variable to read the value into
* @cond: Break condition (usually involving @val)
* @sleep_us: Maximum time to sleep between reads in us (0 tight-loops). Please
* read usleep_range() function description for details and
* limitations.
* @timeout_us: Timeout in us, 0 means never timeout
*
* When available, you'll probably want to use one of the specialized
* macros defined below rather than this macro directly.
*
* Returns: 0 on success and -ETIMEDOUT upon a timeout. In either
* case, the last read value at @addr is stored in @val. Must not
* be called from atomic context if sleep_us or timeout_us are used.
*/
#define readx_poll_timeout(op, addr, val, cond, sleep_us, timeout_us) \
read_poll_timeout(op, val, cond, sleep_us, timeout_us, false, addr)
/**
* readx_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). Please
* read udelay() function description for details and
* limitations.
* @timeout_us: Timeout in us, 0 means never timeout
*
* When available, you'll probably want to use one of the specialized
* macros defined below rather than this macro directly.
*
* Returns: 0 on success and -ETIMEDOUT upon a timeout. In either
* case, the last read value at @addr is stored in @val.
*/
#define readx_poll_timeout_atomic(op, addr, val, cond, delay_us, timeout_us) \
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)
#define readb_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
readx_poll_timeout_atomic(readb, addr, val, cond, delay_us, timeout_us)
#define readw_poll_timeout(addr, val, cond, delay_us, timeout_us) \
readx_poll_timeout(readw, addr, val, cond, delay_us, timeout_us)
#define readw_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
readx_poll_timeout_atomic(readw, addr, val, cond, delay_us, timeout_us)
#define readl_poll_timeout(addr, val, cond, delay_us, timeout_us) \
readx_poll_timeout(readl, addr, val, cond, delay_us, timeout_us)
#define readl_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
readx_poll_timeout_atomic(readl, addr, val, cond, delay_us, timeout_us)
#define readq_poll_timeout(addr, val, cond, delay_us, timeout_us) \
readx_poll_timeout(readq, addr, val, cond, delay_us, timeout_us)
#define readq_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
readx_poll_timeout_atomic(readq, addr, val, cond, delay_us, timeout_us)
#define readb_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
readx_poll_timeout(readb_relaxed, addr, val, cond, delay_us, timeout_us)
#define readb_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
readx_poll_timeout_atomic(readb_relaxed, addr, val, cond, delay_us, timeout_us)
#define readw_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
readx_poll_timeout(readw_relaxed, addr, val, cond, delay_us, timeout_us)
#define readw_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
readx_poll_timeout_atomic(readw_relaxed, addr, val, cond, delay_us, timeout_us)
#define readl_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
readx_poll_timeout(readl_relaxed, addr, val, cond, delay_us, timeout_us)
#define readl_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
readx_poll_timeout_atomic(readl_relaxed, addr, val, cond, delay_us, timeout_us)
#define readq_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
readx_poll_timeout(readq_relaxed, addr, val, cond, delay_us, timeout_us)
#define readq_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
readx_poll_timeout_atomic(readq_relaxed, addr, val, cond, delay_us, timeout_us)
#endif /* _LINUX_IOPOLL_H */