From 0a9df786a6ae2f898114bdd242b64920dedf53bd Mon Sep 17 00:00:00 2001 From: Rasmus Villemoes Date: Fri, 6 Nov 2015 16:31:20 -0800 Subject: lib/kasprintf.c: introduce kvasprintf_const This adds kvasprintf_const which tries to use kstrdup_const if possible: If the format string contains no % characters, or if the format string is exactly "%s", we delegate to kstrdup_const. Otherwise, we fall back to kvasprintf. Just as for kstrdup_const, the main motivation is to save memory by reusing .rodata when possible. The return value should be freed by kfree_const, just like for kstrdup_const. There is deliberately no kasprintf_const: In the vast majority of cases, the format string argument is a literal, so one can determine statically whether one could instead use kstrdup_const directly (which would also require one to change all corresponding kfree calls to kfree_const). Signed-off-by: Rasmus Villemoes Cc: Greg KH Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/kernel.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux/kernel.h') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 5582410727cb..2c13f747ac2e 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -413,6 +413,8 @@ extern __printf(2, 3) char *kasprintf(gfp_t gfp, const char *fmt, ...); extern __printf(2, 0) char *kvasprintf(gfp_t gfp, const char *fmt, va_list args); +extern __printf(2, 0) +const char *kvasprintf_const(gfp_t gfp, const char *fmt, va_list args); extern __scanf(2, 3) int sscanf(const char *, const char *, ...); -- cgit v1.2.3 From c8299cb605b27dd5a49f7a69e48fd23e5a206298 Mon Sep 17 00:00:00 2001 From: Michal Nazarewicz Date: Mon, 9 Nov 2015 14:58:10 -0800 Subject: kernel.h: make abs() work with 64-bit types For 64-bit arguments, the abs macro casts it to an int which leads to lost precision and may cause incorrect results. To deal with 64-bit types abs64 macro has been introduced but still there are places where abs macro is used incorrectly. To deal with the problem, expand abs macro such that it operates on s64 type when dealing with 64-bit types while still returning long when dealing with smaller types. This fixes one known bug (per John): The internal clocksteering done for fine-grained error correction uses a : logarithmic approximation, so any time adjtimex() adjusts the clock : steering, timekeeping_freqadjust() quickly approximates the correct clock : frequency over a series of ticks. : : Unfortunately, the logic in timekeeping_freqadjust(), introduced in commit : dc491596f639438 (Rework frequency adjustments to work better w/ nohz), : used the abs() function with a s64 error value to calculate the size of : the approximated adjustment to be made. : : Per include/linux/kernel.h: "abs() should not be used for 64-bit types : (s64, u64, long long) - use abs64()". : : Thus on 32-bit platforms, this resulted in the clocksteering to take a : quite dampended random walk trying to converge on the proper frequency, : which caused the adjustments to be made much slower then intended (most : easily observed when large adjustments are made). Signed-off-by: Michal Nazarewicz Reported-by: John Stultz Tested-by: John Stultz Cc: Ingo Molnar Cc: Steven Rostedt Cc: Peter Zijlstra Cc: Masami Hiramatsu Cc: Peter Zijlstra Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/kernel.h | 45 ++++++++++++++++++++++++--------------------- 1 file changed, 24 insertions(+), 21 deletions(-) (limited to 'include/linux/kernel.h') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 2c13f747ac2e..05ce782d53ab 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -200,28 +200,31 @@ extern int _cond_resched(void); #define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0) -/* - * abs() handles unsigned and signed longs, ints, shorts and chars. For all - * input types abs() returns a signed long. - * abs() should not be used for 64-bit types (s64, u64, long long) - use abs64() - * for those. +/** + * abs - return absolute value of an argument + * @x: the value. If it is unsigned type, it is converted to signed type first + * (s64, long or int depending on its size). + * + * Return: an absolute value of x. If x is 64-bit, macro's return type is s64, + * otherwise it is signed long. */ -#define abs(x) ({ \ - long ret; \ - if (sizeof(x) == sizeof(long)) { \ - long __x = (x); \ - ret = (__x < 0) ? -__x : __x; \ - } else { \ - int __x = (x); \ - ret = (__x < 0) ? -__x : __x; \ - } \ - ret; \ - }) - -#define abs64(x) ({ \ - s64 __x = (x); \ - (__x < 0) ? -__x : __x; \ - }) +#define abs(x) __builtin_choose_expr(sizeof(x) == sizeof(s64), ({ \ + s64 __x = (x); \ + (__x < 0) ? -__x : __x; \ + }), ({ \ + long ret; \ + if (sizeof(x) == sizeof(long)) { \ + long __x = (x); \ + ret = (__x < 0) ? -__x : __x; \ + } else { \ + int __x = (x); \ + ret = (__x < 0) ? -__x : __x; \ + } \ + ret; \ + })) + +/* Deprecated, use abs instead. */ +#define abs64(x) abs((s64)(x)) /** * reciprocal_scale - "scale" a value into range [0, ep_ro) -- cgit v1.2.3 From 79211c8ed19c055ca105502c8733800d442a0ae6 Mon Sep 17 00:00:00 2001 From: Andrew Morton Date: Mon, 9 Nov 2015 14:58:13 -0800 Subject: remove abs64() Switch everything to the new and more capable implementation of abs(). Mainly to give the new abs() a bit of a workout. Cc: Michal Nazarewicz Cc: John Stultz Cc: Ingo Molnar Cc: Steven Rostedt Cc: Peter Zijlstra Cc: Masami Hiramatsu Cc: Peter Zijlstra Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/gpu/drm/drm_irq.c | 4 ++-- drivers/gpu/drm/tegra/sor.c | 4 ++-- drivers/input/joystick/walkera0701.c | 4 ++-- drivers/media/i2c/ov9650.c | 2 +- drivers/net/wireless/mac80211_hwsim.c | 2 +- drivers/thermal/power_allocator.c | 2 +- fs/ext4/mballoc.c | 4 ++-- fs/gfs2/lock_dlm.c | 2 +- include/linux/kernel.h | 3 --- kernel/time/clocksource.c | 2 +- kernel/time/timekeeping.c | 2 +- lib/div64.c | 2 +- net/sctp/transport.c | 2 +- 13 files changed, 16 insertions(+), 19 deletions(-) (limited to 'include/linux/kernel.h') diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c index 22d207e211e7..22d8b78d537e 100644 --- a/drivers/gpu/drm/drm_irq.c +++ b/drivers/gpu/drm/drm_irq.c @@ -261,7 +261,7 @@ static void vblank_disable_and_save(struct drm_device *dev, unsigned int pipe) * available. In that case we can't account for this and just * hope for the best. */ - if (vblrc && (abs64(diff_ns) > 1000000)) + if (vblrc && (abs(diff_ns) > 1000000)) store_vblank(dev, pipe, 1, &tvblank); spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags); @@ -1772,7 +1772,7 @@ bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe) * e.g., due to spurious vblank interrupts. We need to * ignore those for accounting. */ - if (abs64(diff_ns) > DRM_REDUNDANT_VBLIRQ_THRESH_NS) + if (abs(diff_ns) > DRM_REDUNDANT_VBLIRQ_THRESH_NS) store_vblank(dev, pipe, 1, &tvblank); else DRM_DEBUG("crtc %u: Redundant vblirq ignored. diff_ns = %d\n", diff --git a/drivers/gpu/drm/tegra/sor.c b/drivers/gpu/drm/tegra/sor.c index da1715ebdd71..3eff7cf75d25 100644 --- a/drivers/gpu/drm/tegra/sor.c +++ b/drivers/gpu/drm/tegra/sor.c @@ -555,11 +555,11 @@ static int tegra_sor_compute_params(struct tegra_sor *sor, error = div_s64(active_sym - approx, tu_size); error *= params->num_clocks; - if (error <= 0 && abs64(error) < params->error) { + if (error <= 0 && abs(error) < params->error) { params->active_count = div_u64(active_count, f); params->active_polarity = active_polarity; params->active_frac = active_frac; - params->error = abs64(error); + params->error = abs(error); params->tu_size = tu_size; if (error == 0) diff --git a/drivers/input/joystick/walkera0701.c b/drivers/input/joystick/walkera0701.c index d88f5dd3c9d9..9c07fe911075 100644 --- a/drivers/input/joystick/walkera0701.c +++ b/drivers/input/joystick/walkera0701.c @@ -150,7 +150,7 @@ static void walkera0701_irq_handler(void *handler_data) if (w->counter == 24) { /* full frame */ walkera0701_parse_frame(w); w->counter = NO_SYNC; - if (abs64(pulse_time - SYNC_PULSE) < RESERVE) /* new frame sync */ + if (abs(pulse_time - SYNC_PULSE) < RESERVE) /* new frame sync */ w->counter = 0; } else { if ((pulse_time > (ANALOG_MIN_PULSE - RESERVE) @@ -161,7 +161,7 @@ static void walkera0701_irq_handler(void *handler_data) } else w->counter = NO_SYNC; } - } else if (abs64(pulse_time - SYNC_PULSE - BIN0_PULSE) < + } else if (abs(pulse_time - SYNC_PULSE - BIN0_PULSE) < RESERVE + BIN1_PULSE - BIN0_PULSE) /* frame sync .. */ w->counter = 0; diff --git a/drivers/media/i2c/ov9650.c b/drivers/media/i2c/ov9650.c index e691bba1945b..1ee6a5527c38 100644 --- a/drivers/media/i2c/ov9650.c +++ b/drivers/media/i2c/ov9650.c @@ -1133,7 +1133,7 @@ static int __ov965x_set_frame_interval(struct ov965x *ov965x, if (mbus_fmt->width != iv->size.width || mbus_fmt->height != iv->size.height) continue; - err = abs64((u64)(iv->interval.numerator * 10000) / + err = abs((u64)(iv->interval.numerator * 10000) / iv->interval.denominator - req_int); if (err < min_err) { fiv = iv; diff --git a/drivers/net/wireless/mac80211_hwsim.c b/drivers/net/wireless/mac80211_hwsim.c index ee46f4647fbc..c00a7daaa4bc 100644 --- a/drivers/net/wireless/mac80211_hwsim.c +++ b/drivers/net/wireless/mac80211_hwsim.c @@ -787,7 +787,7 @@ static void mac80211_hwsim_set_tsf(struct ieee80211_hw *hw, struct mac80211_hwsim_data *data = hw->priv; u64 now = mac80211_hwsim_get_tsf(hw, vif); u32 bcn_int = data->beacon_int; - u64 delta = abs64(tsf - now); + u64 delta = abs(tsf - now); /* adjust after beaconing with new timestamp at old TBTT */ if (tsf > now) { diff --git a/drivers/thermal/power_allocator.c b/drivers/thermal/power_allocator.c index e570ff084add..f0fbea386869 100644 --- a/drivers/thermal/power_allocator.c +++ b/drivers/thermal/power_allocator.c @@ -228,7 +228,7 @@ static u32 pid_controller(struct thermal_zone_device *tz, if (err < int_to_frac(tz->tzp->integral_cutoff)) { s64 i_next = i + mul_frac(tz->tzp->k_i, err); - if (abs64(i_next) < max_power_frac) { + if (abs(i_next) < max_power_frac) { i = i_next; params->err_integral += err; } diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index b4b3c1f91814..61eaf74dca37 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -3333,8 +3333,8 @@ ext4_mb_check_group_pa(ext4_fsblk_t goal_block, atomic_inc(&pa->pa_count); return pa; } - cur_distance = abs64(goal_block - cpa->pa_pstart); - new_distance = abs64(goal_block - pa->pa_pstart); + cur_distance = abs(goal_block - cpa->pa_pstart); + new_distance = abs(goal_block - pa->pa_pstart); if (cur_distance <= new_distance) return cpa; diff --git a/fs/gfs2/lock_dlm.c b/fs/gfs2/lock_dlm.c index 284c1542783e..8b907c5cc913 100644 --- a/fs/gfs2/lock_dlm.c +++ b/fs/gfs2/lock_dlm.c @@ -50,7 +50,7 @@ static inline void gfs2_update_stats(struct gfs2_lkstats *s, unsigned index, s64 delta = sample - s->stats[index]; s->stats[index] += (delta >> 3); index++; - s->stats[index] += ((abs64(delta) - s->stats[index]) >> 2); + s->stats[index] += ((abs(delta) - s->stats[index]) >> 2); } /** diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 05ce782d53ab..350dfb08aee3 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -223,9 +223,6 @@ extern int _cond_resched(void); ret; \ })) -/* Deprecated, use abs instead. */ -#define abs64(x) abs((s64)(x)) - /** * reciprocal_scale - "scale" a value into range [0, ep_ro) * @val: value diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c index 0d8fe8b8f727..1347882d131e 100644 --- a/kernel/time/clocksource.c +++ b/kernel/time/clocksource.c @@ -217,7 +217,7 @@ static void clocksource_watchdog(unsigned long data) continue; /* Check the deviation from the watchdog clocksource. */ - if (abs64(cs_nsec - wd_nsec) > WATCHDOG_THRESHOLD) { + if (abs(cs_nsec - wd_nsec) > WATCHDOG_THRESHOLD) { pr_warn("timekeeping watchdog: Marking clocksource '%s' as unstable because the skew is too large:\n", cs->name); pr_warn(" '%s' wd_now: %llx wd_last: %llx mask: %llx\n", diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index b1356b7ae570..d563c1960302 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -1614,7 +1614,7 @@ static __always_inline void timekeeping_freqadjust(struct timekeeper *tk, negative = (tick_error < 0); /* Sort out the magnitude of the correction */ - tick_error = abs64(tick_error); + tick_error = abs(tick_error); for (adj = 0; tick_error > interval; adj++) tick_error >>= 1; diff --git a/lib/div64.c b/lib/div64.c index 19ea7ed4b948..62a698a432bc 100644 --- a/lib/div64.c +++ b/lib/div64.c @@ -162,7 +162,7 @@ s64 div64_s64(s64 dividend, s64 divisor) { s64 quot, t; - quot = div64_u64(abs64(dividend), abs64(divisor)); + quot = div64_u64(abs(dividend), abs(divisor)); t = (dividend ^ divisor) >> 63; return (quot ^ t) - t; diff --git a/net/sctp/transport.c b/net/sctp/transport.c index a0a431824f63..aab9e3f29755 100644 --- a/net/sctp/transport.c +++ b/net/sctp/transport.c @@ -331,7 +331,7 @@ void sctp_transport_update_rto(struct sctp_transport *tp, __u32 rtt) * 1/8, rto_alpha would be expressed as 3. */ tp->rttvar = tp->rttvar - (tp->rttvar >> net->sctp.rto_beta) - + (((__u32)abs64((__s64)tp->srtt - (__s64)rtt)) >> net->sctp.rto_beta); + + (((__u32)abs((__s64)tp->srtt - (__s64)rtt)) >> net->sctp.rto_beta); tp->srtt = tp->srtt - (tp->srtt >> net->sctp.rto_alpha) + (rtt >> net->sctp.rto_alpha); } else { -- cgit v1.2.3