kernel/linux.git/lib/ratelimit.c, branch v6.19.11

lib: ratelimit: fix spelling mistake 'seperately'

2025-11-20T22:03:45+00:00

Corrects a spelling mistake in a comment in ratelimit.c where 'seperately' was used instead of 'separately'. Link: https://lkml.kernel.org/r/20251119101144.3175-1-a0979625527@icloud.com Signed-off-by: Chia-Liang Wang Signed-off-by: Andrew Morton

ratelimit: Drop redundant accesses to burst

2025-05-08T23:13:27+00:00

Now that there is the "burst <= 0" fastpath, for all later code, burst must be strictly greater than zero. Therefore, drop the redundant checks of this local variable. Link: https://lore.kernel.org/all/fbe93a52-365e-47fe-93a4-44a44547d601@paulmck-laptop/ Link: https://lore.kernel.org/all/20250423115409.3425-1-spasswolf@web.de/ Signed-off-by: Paul E. McKenney Reviewed-by: Petr Mladek Cc: Andrew Morton Cc: Kuniyuki Iwashima Cc: Mateusz Guzik Cc: Steven Rostedt Cc: John Ogness Cc: Sergey Senozhatsky

ratelimit: Use nolock_ret restructuring to collapse common case code

2025-05-08T23:13:27+00:00

Now that unlock_ret releases the lock, then falls into nolock_ret, which handles ->missed based on the value of ret, the common-case lock-held code can be collapsed into a single "if" statement with a single-statement "then" clause. Yes, we could go further and just assign the "if" condition to ret, but in the immortal words of MSDOS, "Are you sure?". Link: https://lore.kernel.org/all/fbe93a52-365e-47fe-93a4-44a44547d601@paulmck-laptop/ Link: https://lore.kernel.org/all/20250423115409.3425-1-spasswolf@web.de/ Signed-off-by: Paul E. McKenney Reviewed-by: Petr Mladek Cc: Andrew Morton Cc: Kuniyuki Iwashima Cc: Mateusz Guzik Cc: Steven Rostedt Cc: John Ogness Cc: Sergey Senozhatsky

ratelimit: Use nolock_ret label to collapse lock-failure code

2025-05-08T23:13:27+00:00

Now that we have a nolock_ret label that handles ->missed correctly based on the value of ret, we can eliminate a local variable and collapse several "if" statements on the lock-acquisition-failure code path. Link: https://lore.kernel.org/all/fbe93a52-365e-47fe-93a4-44a44547d601@paulmck-laptop/ Link: https://lore.kernel.org/all/20250423115409.3425-1-spasswolf@web.de/ Signed-off-by: Paul E. McKenney Reviewed-by: Petr Mladek Cc: Andrew Morton Cc: Kuniyuki Iwashima Cc: Mateusz Guzik Cc: Steven Rostedt Cc: John Ogness Cc: Sergey Senozhatsky

ratelimit: Use nolock_ret label to save a couple of lines of code

2025-05-08T23:13:27+00:00

Create a nolock_ret label in order to start consolidating the unlocked return paths that conditionally invoke ratelimit_state_inc_miss(). Link: https://lore.kernel.org/all/fbe93a52-365e-47fe-93a4-44a44547d601@paulmck-laptop/ Link: https://lore.kernel.org/all/20250423115409.3425-1-spasswolf@web.de/ Signed-off-by: Paul E. McKenney Reviewed-by: Petr Mladek Cc: Andrew Morton Cc: Kuniyuki Iwashima Cc: Mateusz Guzik Cc: Steven Rostedt Cc: John Ogness Cc: Sergey Senozhatsky

ratelimit: Simplify common-case exit path

2025-05-08T23:13:27+00:00

By making "ret" always be initialized, and moving the final call to ratelimit_state_inc_miss() out from under the lock, we save a goto and a couple lines of code. This also saves a couple of lines of code from the unconditional enable/disable slowpath. Link: https://lore.kernel.org/all/fbe93a52-365e-47fe-93a4-44a44547d601@paulmck-laptop/ Link: https://lore.kernel.org/all/20250423115409.3425-1-spasswolf@web.de/ Signed-off-by: Paul E. McKenney Reviewed-by: Petr Mladek Cc: Andrew Morton Cc: Kuniyuki Iwashima Cc: Mateusz Guzik Cc: Steven Rostedt Cc: John Ogness Cc: Sergey Senozhatsky

ratelimit: Warn if ->interval or ->burst are negative

2025-05-08T23:13:27+00:00

Currently, ___ratelimit() treats a negative ->interval or ->burst as if it was zero, but this is an accident of the current implementation. Therefore, splat in this case, which might have the benefit of detecting use of uninitialized ratelimit_state structures on the one hand or easing addition of new features on the other. Link: https://lore.kernel.org/all/fbe93a52-365e-47fe-93a4-44a44547d601@paulmck-laptop/ Link: https://lore.kernel.org/all/20250423115409.3425-1-spasswolf@web.de/ Signed-off-by: Petr Mladek Signed-off-by: Paul E. McKenney Cc: Andrew Morton Cc: Kuniyuki Iwashima Cc: Mateusz Guzik Cc: Steven Rostedt Cc: John Ogness Cc: Sergey Senozhatsky

ratelimit: Avoid atomic decrement under lock if already rate-limited

2025-05-08T23:13:27+00:00

Currently, if the lock is acquired, the code unconditionally does an atomic decrement on ->rs_n_left, even if that atomic operation is guaranteed to return a limit-rate verdict. A limit-rate verdict will in fact be the common case when something is spewing into a rate limit. This unconditional atomic operation incurs needless overhead and also raises the spectre of counter wrap. Therefore, do the atomic decrement only if there is some chance that rates won't be limited. Link: https://lore.kernel.org/all/fbe93a52-365e-47fe-93a4-44a44547d601@paulmck-laptop/ Link: https://lore.kernel.org/all/20250423115409.3425-1-spasswolf@web.de/ Signed-off-by: Paul E. McKenney Reviewed-by: Petr Mladek Cc: Andrew Morton Cc: Kuniyuki Iwashima Cc: Mateusz Guzik Cc: Steven Rostedt Cc: John Ogness Cc: Sergey Senozhatsky

ratelimit: Avoid atomic decrement if already rate-limited

2025-05-08T23:13:27+00:00

Currently, if the lock could not be acquired, the code unconditionally does an atomic decrement on ->rs_n_left, even if that atomic operation is guaranteed to return a limit-rate verdict. This incurs needless overhead and also raises the spectre of counter wrap. Therefore, do the atomic decrement only if there is some chance that rates won't be limited. Link: https://lore.kernel.org/all/fbe93a52-365e-47fe-93a4-44a44547d601@paulmck-laptop/ Link: https://lore.kernel.org/all/20250423115409.3425-1-spasswolf@web.de/ Signed-off-by: Paul E. McKenney Reviewed-by: Petr Mladek Cc: Andrew Morton Cc: Kuniyuki Iwashima Cc: Mateusz Guzik Cc: Steven Rostedt Cc: John Ogness Cc: Sergey Senozhatsky

ratelimit: Don't flush misses counter if RATELIMIT_MSG_ON_RELEASE

2025-05-08T23:13:27+00:00

Restore the previous semantics where the misses counter is unchanged if the RATELIMIT_MSG_ON_RELEASE flag is set. Link: https://lore.kernel.org/all/fbe93a52-365e-47fe-93a4-44a44547d601@paulmck-laptop/ Link: https://lore.kernel.org/all/20250423115409.3425-1-spasswolf@web.de/ Signed-off-by: Paul E. McKenney Reviewed-by: Petr Mladek Cc: Andrew Morton Cc: Kuniyuki Iwashima Cc: Mateusz Guzik Cc: Steven Rostedt Cc: John Ogness Cc: Sergey Senozhatsky