diff options
Diffstat (limited to 'debian/patches-rt/0346-rcu-Update-rcuwait.patch')
| -rw-r--r-- | debian/patches-rt/0346-rcu-Update-rcuwait.patch | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/debian/patches-rt/0346-rcu-Update-rcuwait.patch b/debian/patches-rt/0346-rcu-Update-rcuwait.patch new file mode 100644 index 000000000..c54c65f9c --- /dev/null +++ b/debian/patches-rt/0346-rcu-Update-rcuwait.patch @@ -0,0 +1,176 @@ +From: Daniel Wagner <wagi@monom.org> +Date: Mon, 24 Oct 2022 10:58:29 +0200 +Subject: [PATCH 346/351] rcu: Update rcuwait +Origin: https://git.kernel.org/cgit/linux/kernel/git/rt/linux-stable-rt.git/commit?id=6f1be9e81d653b56aeefbff1883d1f762e8b594e + +This is an all in one commit backporting updates for rcuwait: + - 03f4b48edae7 ("rcuwait: Annotate task_struct with __rcu") + - 191a43be61d6 ("rcuwait: Introduce rcuwait_active()") + - 5c21f7b322cb ("rcuwait: Introduce prepare_to and finish_rcuwait") + - 80fbaf1c3f29 ("rcuwait: Add @state argument to rcuwait_wait_event()") + - 9d9a6ebfea32 ("rcuwait: Let rcuwait_wake_up() return whether or not a task was awoken") + - 58d4292bd037 ("rcu: Uninline multi-use function: finish_rcuwait()") + +Signed-off-by: Daniel Wagner <wagi@monom.org> +--- + include/linux/rcuwait.h | 42 +++++++++++++++++++++++++++-------- + kernel/exit.c | 7 ++++-- + kernel/locking/percpu-rwsem.c | 2 +- + kernel/rcu/update.c | 8 +++++++ + 4 files changed, 47 insertions(+), 12 deletions(-) + +diff --git a/include/linux/rcuwait.h b/include/linux/rcuwait.h +index 90bfa3279a01..4fe9ecd56aac 100644 +--- a/include/linux/rcuwait.h ++++ b/include/linux/rcuwait.h +@@ -3,6 +3,7 @@ + #define _LINUX_RCUWAIT_H_ + + #include <linux/rcupdate.h> ++#include <linux/sched/signal.h> + + /* + * rcuwait provides a way of blocking and waking up a single +@@ -18,7 +19,7 @@ + * awoken. + */ + struct rcuwait { +- struct task_struct *task; ++ struct task_struct __rcu *task; + }; + + #define __RCUWAIT_INITIALIZER(name) \ +@@ -29,14 +30,33 @@ static inline void rcuwait_init(struct rcuwait *w) + w->task = NULL; + } + +-extern void rcuwait_wake_up(struct rcuwait *w); ++extern int rcuwait_wake_up(struct rcuwait *w); ++ ++/* ++ * Note: this provides no serialization and, just as with waitqueues, ++ * requires care to estimate as to whether or not the wait is active. ++ */ ++static inline int rcuwait_active(struct rcuwait *w) ++{ ++ return !!rcu_access_pointer(w->task); ++} + + /* + * The caller is responsible for locking around rcuwait_wait_event(), +- * such that writes to @task are properly serialized. ++ * and [prepare_to/finish]_rcuwait() such that writes to @task are ++ * properly serialized. + */ +-#define rcuwait_wait_event(w, condition) \ ++ ++static inline void prepare_to_rcuwait(struct rcuwait *w) ++{ ++ rcu_assign_pointer(w->task, current); ++} ++ ++extern void finish_rcuwait(struct rcuwait *w); ++ ++#define rcuwait_wait_event(w, condition, state) \ + ({ \ ++ int __ret = 0; \ + /* \ + * Complain if we are called after do_exit()/exit_notify(), \ + * as we cannot rely on the rcu critical region for the \ +@@ -44,21 +64,25 @@ extern void rcuwait_wake_up(struct rcuwait *w); + */ \ + WARN_ON(current->exit_state); \ + \ +- rcu_assign_pointer((w)->task, current); \ ++ prepare_to_rcuwait(w); \ + for (;;) { \ + /* \ + * Implicit barrier (A) pairs with (B) in \ + * rcuwait_wake_up(). \ + */ \ +- set_current_state(TASK_UNINTERRUPTIBLE); \ ++ set_current_state(state); \ + if (condition) \ + break; \ + \ ++ if (signal_pending_state(state, current)) { \ ++ __ret = -EINTR; \ ++ break; \ ++ } \ ++ \ + schedule(); \ + } \ +- \ +- WRITE_ONCE((w)->task, NULL); \ +- __set_current_state(TASK_RUNNING); \ ++ finish_rcuwait(w); \ ++ __ret; \ + }) + + #endif /* _LINUX_RCUWAIT_H_ */ +diff --git a/kernel/exit.c b/kernel/exit.c +index 2a414fc71b87..cf68896a94fa 100644 +--- a/kernel/exit.c ++++ b/kernel/exit.c +@@ -291,8 +291,9 @@ struct task_struct *task_rcu_dereference(struct task_struct **ptask) + return task; + } + +-void rcuwait_wake_up(struct rcuwait *w) ++int rcuwait_wake_up(struct rcuwait *w) + { ++ int ret = 0; + struct task_struct *task; + + rcu_read_lock(); +@@ -316,8 +317,10 @@ void rcuwait_wake_up(struct rcuwait *w) + */ + task = rcu_dereference(w->task); + if (task) +- wake_up_process(task); ++ ret = wake_up_process(task); + rcu_read_unlock(); ++ ++ return ret; + } + + /* +diff --git a/kernel/locking/percpu-rwsem.c b/kernel/locking/percpu-rwsem.c +index 883cf1b92d90..41787e80dbde 100644 +--- a/kernel/locking/percpu-rwsem.c ++++ b/kernel/locking/percpu-rwsem.c +@@ -159,7 +159,7 @@ void percpu_down_write(struct percpu_rw_semaphore *sem) + */ + + /* Wait for all now active readers to complete. */ +- rcuwait_wait_event(&sem->writer, readers_active_check(sem)); ++ rcuwait_wait_event(&sem->writer, readers_active_check(sem), TASK_UNINTERRUPTIBLE); + } + EXPORT_SYMBOL_GPL(percpu_down_write); + +diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c +index ed75addd3ccd..4b2ce6bb94a4 100644 +--- a/kernel/rcu/update.c ++++ b/kernel/rcu/update.c +@@ -53,6 +53,7 @@ + #include <linux/rcupdate_wait.h> + #include <linux/sched/isolation.h> + #include <linux/kprobes.h> ++#include <linux/rcuwait.h> + + #define CREATE_TRACE_POINTS + +@@ -375,6 +376,13 @@ void __wait_rcu_gp(bool checktiny, int n, call_rcu_func_t *crcu_array, + } + EXPORT_SYMBOL_GPL(__wait_rcu_gp); + ++void finish_rcuwait(struct rcuwait *w) ++{ ++ rcu_assign_pointer(w->task, NULL); ++ __set_current_state(TASK_RUNNING); ++} ++EXPORT_SYMBOL_GPL(finish_rcuwait); ++ + #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD + void init_rcu_head(struct rcu_head *head) + { |