From 45dbac0e288350f9a4226a5b4b651ed434dd9f85 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Thu, 15 Mar 2018 04:58:12 -0700 Subject: locking/mutex: Improve documentation On Wed, Mar 14, 2018 at 01:56:31PM -0700, Andrew Morton wrote: > My memory is weak and our documentation is awful. What does > mutex_lock_killable() actually do and how does it differ from > mutex_lock_interruptible()? Add kernel-doc for mutex_lock_killable() and mutex_lock_io(). Reword the kernel-doc for mutex_lock_interruptible(). Signed-off-by: Matthew Wilcox Signed-off-by: Peter Zijlstra (Intel) Cc: Andrew Morton Cc: Jonathan Corbet Cc: Kirill Tkhai Cc: Linus Torvalds Cc: Mauro Carvalho Chehab Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: cl@linux.com Cc: tj@kernel.org Link: http://lkml.kernel.org/r/20180315115812.GA9949@bombadil.infradead.org Signed-off-by: Ingo Molnar --- kernel/locking/mutex.c | 37 ++++++++++++++++++++++++++++++------- 1 file changed, 30 insertions(+), 7 deletions(-) (limited to 'kernel') diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c index 858a07590e39..2048359f33d2 100644 --- a/kernel/locking/mutex.c +++ b/kernel/locking/mutex.c @@ -1082,15 +1082,16 @@ static noinline int __sched __mutex_lock_interruptible_slowpath(struct mutex *lock); /** - * mutex_lock_interruptible - acquire the mutex, interruptible - * @lock: the mutex to be acquired + * mutex_lock_interruptible() - Acquire the mutex, interruptible by signals. + * @lock: The mutex to be acquired. * - * Lock the mutex like mutex_lock(), and return 0 if the mutex has - * been acquired or sleep until the mutex becomes available. If a - * signal arrives while waiting for the lock then this function - * returns -EINTR. + * Lock the mutex like mutex_lock(). If a signal is delivered while the + * process is sleeping, this function will return without acquiring the + * mutex. * - * This function is similar to (but not equivalent to) down_interruptible(). + * Context: Process context. + * Return: 0 if the lock was successfully acquired or %-EINTR if a + * signal arrived. */ int __sched mutex_lock_interruptible(struct mutex *lock) { @@ -1104,6 +1105,18 @@ int __sched mutex_lock_interruptible(struct mutex *lock) EXPORT_SYMBOL(mutex_lock_interruptible); +/** + * mutex_lock_killable() - Acquire the mutex, interruptible by fatal signals. + * @lock: The mutex to be acquired. + * + * Lock the mutex like mutex_lock(). If a signal which will be fatal to + * the current process is delivered while the process is sleeping, this + * function will return without acquiring the mutex. + * + * Context: Process context. + * Return: 0 if the lock was successfully acquired or %-EINTR if a + * fatal signal arrived. + */ int __sched mutex_lock_killable(struct mutex *lock) { might_sleep(); @@ -1115,6 +1128,16 @@ int __sched mutex_lock_killable(struct mutex *lock) } EXPORT_SYMBOL(mutex_lock_killable); +/** + * mutex_lock_io() - Acquire the mutex and mark the process as waiting for I/O + * @lock: The mutex to be acquired. + * + * Lock the mutex like mutex_lock(). While the task is waiting for this + * mutex, it will be accounted as being in the IO wait state by the + * scheduler. + * + * Context: Process context. + */ void __sched mutex_lock_io(struct mutex *lock) { int token; -- cgit v1.2.3 From 578ae447e7e5d78c90ac40a06406c1741f79ba96 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Mon, 19 Mar 2018 13:18:57 -0500 Subject: jump_label: Disable jump labels in __exit code With the following commit: 333522447063 ("jump_label: Explicitly disable jump labels in __init code") ... we explicitly disabled jump labels in __init code, so they could be detected and not warned about in the following commit: dc1dd184c2f0 ("jump_label: Warn on failed jump_label patching attempt") In-kernel __exit code has the same issue. It's never used, so it's freed along with the rest of initmem. But jump label entries in __exit code aren't explicitly disabled, so we get the following warning when enabling pr_debug() in __exit code: can't patch jump_label at dmi_sysfs_exit+0x0/0x2d WARNING: CPU: 0 PID: 22572 at kernel/jump_label.c:376 __jump_label_update+0x9d/0xb0 Fix the warning by disabling all jump labels in initmem (which includes both __init and __exit code). Reported-and-tested-by: Li Wang Signed-off-by: Josh Poimboeuf Cc: Borislav Petkov Cc: Jason Baron Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Fixes: dc1dd184c2f0 ("jump_label: Warn on failed jump_label patching attempt") Link: http://lkml.kernel.org/r/7121e6e595374f06616c505b6e690e275c0054d1.1521483452.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar --- include/linux/jump_label.h | 4 ++-- init/main.c | 2 +- kernel/jump_label.c | 7 ++++--- 3 files changed, 7 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h index 2168cc6b8b30..b46b541c67c4 100644 --- a/include/linux/jump_label.h +++ b/include/linux/jump_label.h @@ -151,7 +151,7 @@ extern struct jump_entry __start___jump_table[]; extern struct jump_entry __stop___jump_table[]; extern void jump_label_init(void); -extern void jump_label_invalidate_init(void); +extern void jump_label_invalidate_initmem(void); extern void jump_label_lock(void); extern void jump_label_unlock(void); extern void arch_jump_label_transform(struct jump_entry *entry, @@ -199,7 +199,7 @@ static __always_inline void jump_label_init(void) static_key_initialized = true; } -static inline void jump_label_invalidate_init(void) {} +static inline void jump_label_invalidate_initmem(void) {} static __always_inline bool static_key_false(struct static_key *key) { diff --git a/init/main.c b/init/main.c index 969eaf140ef0..21efbf6ace93 100644 --- a/init/main.c +++ b/init/main.c @@ -1001,7 +1001,7 @@ static int __ref kernel_init(void *unused) /* need to finish all async __init code before freeing the memory */ async_synchronize_full(); ftrace_free_init_mem(); - jump_label_invalidate_init(); + jump_label_invalidate_initmem(); free_initmem(); mark_readonly(); system_state = SYSTEM_RUNNING; diff --git a/kernel/jump_label.c b/kernel/jump_label.c index e7214093dcd1..01ebdf1f9f40 100644 --- a/kernel/jump_label.c +++ b/kernel/jump_label.c @@ -16,6 +16,7 @@ #include #include #include +#include #ifdef HAVE_JUMP_LABEL @@ -421,15 +422,15 @@ void __init jump_label_init(void) cpus_read_unlock(); } -/* Disable any jump label entries in __init code */ -void __init jump_label_invalidate_init(void) +/* Disable any jump label entries in __init/__exit code */ +void __init jump_label_invalidate_initmem(void) { struct jump_entry *iter_start = __start___jump_table; struct jump_entry *iter_stop = __stop___jump_table; struct jump_entry *iter; for (iter = iter_start; iter < iter_stop; iter++) { - if (init_kernel_text(iter->code)) + if (init_section_contains((void *)(unsigned long)iter->code, 1)) iter->code = 0; } } -- cgit v1.2.3