d15809f364
When we pass the result of a multiplication as the timeout or the delay, we can get a warning from gcc-7: drivers/mmc/host/bcm2835.c:596:149: error: '*' in boolean context, suggest '&&' instead [-Werror=int-in-bool-context] drivers/mfd/arizona-core.c:247:195: error: '*' in boolean context, suggest '&&' instead [-Werror=int-in-bool-context] drivers/gpu/drm/sun4i/sun4i_hdmi_i2c.c:49:27: error: '*' in boolean context, suggest '&&' instead [-Werror=int-in-bool-context] The warning is a bit questionable inside of a macro, but this is intentional on the side of the gcc developers. It is also an indication of another problem: we evaluate the timeout and sleep arguments multiple times, which can have undesired side-effects when those are complex expressions. This changes the two iopoll variants to use local variables for storing copies of the timeouts. This adds some more type safety, and avoids both the double-evaluation and the gcc warning. Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81484 Link: http://lkml.kernel.org/r/20170726133756.2161367-1-arnd@arndb.de Link: http://lkml.kernel.org/r/20171102114048.1526955-1-arnd@arndb.de Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Mark Brown <broonie@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
150 lines
5.7 KiB
C
150 lines
5.7 KiB
C
/*
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* Copyright (c) 2012-2014 The Linux Foundation. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 and
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* only version 2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*/
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#ifndef _LINUX_IOPOLL_H
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#define _LINUX_IOPOLL_H
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#include <linux/kernel.h>
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#include <linux/types.h>
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#include <linux/ktime.h>
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#include <linux/delay.h>
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#include <linux/errno.h>
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#include <linux/io.h>
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/**
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* readx_poll_timeout - Periodically poll an address until a condition is met or a timeout occurs
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* @op: accessor function (takes @addr as its only argument)
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* @addr: Address to poll
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* @val: Variable to read the value into
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* @cond: Break condition (usually involving @val)
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* @sleep_us: Maximum time to sleep between reads in us (0
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* tight-loops). Should be less than ~20ms since usleep_range
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* is used (see Documentation/timers/timers-howto.txt).
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* @timeout_us: Timeout in us, 0 means never timeout
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*
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* Returns 0 on success and -ETIMEDOUT upon a timeout. In either
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* case, the last read value at @addr is stored in @val. Must not
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* be called from atomic context if sleep_us or timeout_us are used.
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*
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* When available, you'll probably want to use one of the specialized
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* macros defined below rather than this macro directly.
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*/
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#define readx_poll_timeout(op, addr, val, cond, sleep_us, timeout_us) \
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({ \
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u64 __timeout_us = (timeout_us); \
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unsigned long __sleep_us = (sleep_us); \
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ktime_t __timeout = ktime_add_us(ktime_get(), __timeout_us); \
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might_sleep_if((__sleep_us) != 0); \
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for (;;) { \
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(val) = op(addr); \
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if (cond) \
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break; \
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if (__timeout_us && \
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ktime_compare(ktime_get(), __timeout) > 0) { \
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(val) = op(addr); \
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break; \
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} \
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if (__sleep_us) \
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usleep_range((__sleep_us >> 2) + 1, __sleep_us); \
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} \
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(cond) ? 0 : -ETIMEDOUT; \
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})
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/**
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* readx_poll_timeout_atomic - Periodically poll an address until a condition is met or a timeout occurs
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* @op: accessor function (takes @addr as its only argument)
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* @addr: Address to poll
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* @val: Variable to read the value into
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* @cond: Break condition (usually involving @val)
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* @delay_us: Time to udelay between reads in us (0 tight-loops). Should
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* be less than ~10us since udelay is used (see
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* Documentation/timers/timers-howto.txt).
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* @timeout_us: Timeout in us, 0 means never timeout
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*
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* Returns 0 on success and -ETIMEDOUT upon a timeout. In either
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* case, the last read value at @addr is stored in @val.
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*
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* When available, you'll probably want to use one of the specialized
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* macros defined below rather than this macro directly.
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*/
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#define readx_poll_timeout_atomic(op, addr, val, cond, delay_us, timeout_us) \
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({ \
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u64 __timeout_us = (timeout_us); \
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unsigned long __delay_us = (delay_us); \
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ktime_t __timeout = ktime_add_us(ktime_get(), __timeout_us); \
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for (;;) { \
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(val) = op(addr); \
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if (cond) \
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break; \
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if (__timeout_us && \
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ktime_compare(ktime_get(), __timeout) > 0) { \
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(val) = op(addr); \
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break; \
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} \
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if (__delay_us) \
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udelay(__delay_us); \
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} \
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(cond) ? 0 : -ETIMEDOUT; \
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})
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#define readb_poll_timeout(addr, val, cond, delay_us, timeout_us) \
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readx_poll_timeout(readb, addr, val, cond, delay_us, timeout_us)
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#define readb_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
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readx_poll_timeout_atomic(readb, addr, val, cond, delay_us, timeout_us)
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#define readw_poll_timeout(addr, val, cond, delay_us, timeout_us) \
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readx_poll_timeout(readw, addr, val, cond, delay_us, timeout_us)
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#define readw_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
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readx_poll_timeout_atomic(readw, addr, val, cond, delay_us, timeout_us)
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#define readl_poll_timeout(addr, val, cond, delay_us, timeout_us) \
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readx_poll_timeout(readl, addr, val, cond, delay_us, timeout_us)
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#define readl_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
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readx_poll_timeout_atomic(readl, addr, val, cond, delay_us, timeout_us)
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#define readq_poll_timeout(addr, val, cond, delay_us, timeout_us) \
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readx_poll_timeout(readq, addr, val, cond, delay_us, timeout_us)
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#define readq_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
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readx_poll_timeout_atomic(readq, addr, val, cond, delay_us, timeout_us)
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#define readb_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
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readx_poll_timeout(readb_relaxed, addr, val, cond, delay_us, timeout_us)
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#define readb_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
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readx_poll_timeout_atomic(readb_relaxed, addr, val, cond, delay_us, timeout_us)
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#define readw_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
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readx_poll_timeout(readw_relaxed, addr, val, cond, delay_us, timeout_us)
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#define readw_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
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readx_poll_timeout_atomic(readw_relaxed, addr, val, cond, delay_us, timeout_us)
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#define readl_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
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readx_poll_timeout(readl_relaxed, addr, val, cond, delay_us, timeout_us)
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#define readl_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
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readx_poll_timeout_atomic(readl_relaxed, addr, val, cond, delay_us, timeout_us)
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#define readq_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
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readx_poll_timeout(readq_relaxed, addr, val, cond, delay_us, timeout_us)
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#define readq_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
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readx_poll_timeout_atomic(readq_relaxed, addr, val, cond, delay_us, timeout_us)
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#endif /* _LINUX_IOPOLL_H */
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