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(I'm so sorry!) Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596// SPDX-License-Identifier: MIT/* * Timeout conversion helpers for wait ioctls. * * Copyright 2017 Red Hat * Copyright 2016 Advanced Micro Devices, Inc. */
#include <linux/export.h>#include <linux/jiffies.h>#include <linux/ktime.h>#include <linux/math64.h>#include <linux/sched.h>
#include <drm/drm_timeout.h>
/** * drm_timeout_abs_to_jiffies - calculate jiffies timeout from absolute value * @timeout_nsec: timeout nsec component in ns, 0 for poll * * Calculate the timeout in jiffies from an absolute time in ns. The result is * clamped to MAX_SCHEDULE_TIMEOUT - 1 to avoid infinite timeouts. * * Returns: * The number of jiffies until the given timeout, or the upper limit. */signed long drm_timeout_abs_to_jiffies(s64 timeout_nsec){ ktime_t abs_timeout, now; u64 timeout_ns, timeout_jiffies64;
/* make 0 timeout means poll - absolute 0 doesn't seem valid */ if (timeout_nsec == 0) return 0;
abs_timeout = ns_to_ktime(timeout_nsec); now = ktime_get();
if (!ktime_after(abs_timeout, now)) return 0;
timeout_ns = ktime_to_ns(ktime_sub(abs_timeout, now));
timeout_jiffies64 = nsecs_to_jiffies64(timeout_ns); /* clamp timeout to avoid infinite timeout */ if (timeout_jiffies64 >= MAX_SCHEDULE_TIMEOUT - 1) return MAX_SCHEDULE_TIMEOUT - 1;
return timeout_jiffies64 + 1;}EXPORT_SYMBOL(drm_timeout_abs_to_jiffies);
/** * drm_timeout_rel_to_jiffies - calculate jiffies timeout from relative value * @timeout_nsec: relative timeout in ns, 0 for poll * * Calculate the timeout in jiffies from a relative timeout in ns, for drivers * whose UAPI expresses a wait as a duration rather than as a deadline. * * The result is clamped to MAX_JIFFY_OFFSET. That keeps it positive once it is * converted to the signed long taken by dma_fence_wait_timeout() and friends, * which matters on 32-bit, and keeps it distinct from MAX_SCHEDULE_TIMEOUT so * that a finite wait is never understood as an infinite one. * * It's strongly discouraged to use relative timeouts in uAPIs, as they do not * survive a restarted ioctl. A signal-interrupted ioctl is re-entered with the * same arguments, so the duration starts counting from zero again. New uAPIs * should take an absolute deadline and use drm_timeout_abs_to_jiffies(). * * Returns: * 0 if @timeout_nsec is 0. Otherwise the equivalent number of jiffies and * clamped to MAX_JIFFY_OFFSET. */unsigned long drm_timeout_rel_to_jiffies(u64 timeout_nsec){ u64 secs; u32 rem;
/* Make 0 timeout means poll, as for the absolute variant. */ if (timeout_nsec == 0) return 0;
/* * As nsecs_to_jiffies64() does not guard against overflow, split * the timeout into whole seconds and nanoseconds. This way * nsecs_to_jiffies64() is always handed a value below a second. */ secs = div_u64_rem(timeout_nsec, NSEC_PER_SEC, &rem); if (secs >= MAX_JIFFY_OFFSET / HZ) return MAX_JIFFY_OFFSET;
return min_t(u64, MAX_JIFFY_OFFSET, secs_to_jiffies(secs) + nsecs_to_jiffies64(rem) + 1);}EXPORT_SYMBOL(drm_timeout_rel_to_jiffies);