From e8dd273d199f5bbe295a8e3d8b777c5505b6b2e1 Mon Sep 17 00:00:00 2001 From: Salah Triki Date: Thu, 17 Sep 2026 14:00:52 +0100 Subject: iio: proximity: isl29501: Fix return type of isl29501_register_write isl29501_register_write() was returning a u32 instead of an int. Since the function returns negative error codes (such as -ERANGE or return values from i2c_smbus_write_byte_data()), returning an unsigned integer type prevents callers from correctly checking for negative error conditions. Fix this by changing the function return type from u32 to int. This was found through manual code review. Fixes: 1c28799257bc ("iio: light: isl29501: Add support for the ISL29501 ToF sensor.") Signed-off-by: Salah Triki Reviewed-by: Joshua Crofts Cc: stable@vger.kernel.org Signed-off-by: Jonathan Cameron --- lib/ratelimit.c | 105 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 105 insertions(+) create mode 100644 lib/ratelimit.c (limited to 'lib/ratelimit.c') diff --git a/lib/ratelimit.c b/lib/ratelimit.c new file mode 100644 index 000000000..e2d65d3b1 --- /dev/null +++ b/lib/ratelimit.c @@ -0,0 +1,105 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * ratelimit.c - Do something with rate limit. + * + * Isolated from kernel/printk.c by Dave Young + * + * 2008-05-01 rewrite the function and use a ratelimit_state data struct as + * parameter. Now every user can use their own standalone ratelimit_state. + */ + +#include +#include +#include + +/* + * __ratelimit - rate limiting + * @rs: ratelimit_state data + * @func: name of calling function + * + * This enforces a rate limit: not more than @rs->burst callbacks + * in every @rs->interval + * + * RETURNS: + * 0 means callbacks will be suppressed. + * 1 means go ahead and do it. + */ +int ___ratelimit(struct ratelimit_state *rs, const char *func) +{ + /* Paired with WRITE_ONCE() in .proc_handler(). + * Changing two values separately could be inconsistent + * and some message could be lost. (See: net_ratelimit_state). + */ + int interval = READ_ONCE(rs->interval); + int burst = READ_ONCE(rs->burst); + unsigned long flags; + int ret = 0; + + /* + * Zero interval says never limit, otherwise, non-positive burst + * says always limit. + */ + if (interval <= 0 || burst <= 0) { + WARN_ONCE(interval < 0 || burst < 0, "Negative interval (%d) or burst (%d): Uninitialized ratelimit_state structure?\n", interval, burst); + ret = interval == 0 || burst > 0; + if (!(READ_ONCE(rs->flags) & RATELIMIT_INITIALIZED) || (!interval && !burst) || + !raw_spin_trylock_irqsave(&rs->lock, flags)) + goto nolock_ret; + + /* Force re-initialization once re-enabled. */ + rs->flags &= ~RATELIMIT_INITIALIZED; + goto unlock_ret; + } + + /* + * If we contend on this state's lock then just check if + * the current burst is used or not. It might cause + * false positive when we are past the interval and + * the current lock owner is just about to reset it. + */ + if (!raw_spin_trylock_irqsave(&rs->lock, flags)) { + if (READ_ONCE(rs->flags) & RATELIMIT_INITIALIZED && + atomic_read(&rs->rs_n_left) > 0 && atomic_dec_return(&rs->rs_n_left) >= 0) + ret = 1; + goto nolock_ret; + } + + if (!(rs->flags & RATELIMIT_INITIALIZED)) { + rs->begin = jiffies; + rs->flags |= RATELIMIT_INITIALIZED; + atomic_set(&rs->rs_n_left, rs->burst); + } + + if (time_is_before_jiffies(rs->begin + interval)) { + int m; + + /* + * Reset rs_n_left ASAP to reduce false positives + * in parallel calls, see above. + */ + atomic_set(&rs->rs_n_left, rs->burst); + rs->begin = jiffies; + + if (!(rs->flags & RATELIMIT_MSG_ON_RELEASE)) { + m = ratelimit_state_reset_miss(rs); + if (m) { + printk_deferred(KERN_WARNING + "%s: %d callbacks suppressed\n", func, m); + } + } + } + + /* Note that the burst might be taken by a parallel call. */ + if (atomic_read(&rs->rs_n_left) > 0 && atomic_dec_return(&rs->rs_n_left) >= 0) + ret = 1; + +unlock_ret: + raw_spin_unlock_irqrestore(&rs->lock, flags); + +nolock_ret: + if (!ret) + ratelimit_state_inc_miss(rs); + + return ret; +} +EXPORT_SYMBOL(___ratelimit); -- cgit v1.3.1