#include #include #include static struct callback_head work_exited; /* all we need is ->next == NULL */ /** * task_work_add - ask the @task to execute @work->func() * @task: the task which should run the callback * @work: the callback to run * @notify: send the notification if true * * Queue @work for task_work_run() below and notify the @task if @notify. * Fails if the @task is exiting/exited and thus it can't process this @work. * Otherwise @work->func() will be called when the @task returns from kernel * mode or exits. * * This is like the signal handler which runs in kernel mode, but it doesn't * try to wake up the @task. * * Note: there is no ordering guarantee on works queued here. * * RETURNS: * 0 if succeeds or -ESRCH. */ int task_work_add(struct task_struct *task, struct callback_head *work, bool notify) { struct callback_head *head; do { head = READ_ONCE(task->task_works); if (unlikely(head == &work_exited)) return -ESRCH; work->next = head; } while (cmpxchg(&task->task_works, head, work) != head); if (notify) set_notify_resume(task); return 0; } /** * task_work_cancel - cancel a pending work added by task_work_add() * @task: the task which should execute the work * @func: identifies the work to remove * * Find the last queued pending work with ->func == @func and remove * it from queue. * * RETURNS: * The found work or NULL if not found. */ struct callback_head * task_work_cancel(struct task_struct *task, task_work_func_t func) { struct callback_head **pprev = &task->task_works; struct callback_head *work; unsigned long flags; if (likely(!task->task_works)) return NULL; /* * If cmpxchg() fails we continue without updating pprev. * Either we raced with task_work_add() which added the * new entry before this work, we will find it again. Or * we raced with task_work_run(), *pprev == NULL/exited. */ raw_spin_lock_irqsave(&task->pi_lock, flags); while ((work = lockless_dereference(*pprev))) { if (work->func != func) pprev = &work->next; else if (cmpxchg(pprev, work, work->next) == work) break; } raw_spin_unlock_irqrestore(&task->pi_lock, flags); return work; } /** * task_work_run - execute the works added by task_work_add() * * Flush the pending works. Should be used by the core kernel code. * Called before the task returns to the user-mode or stops, or when * it exits. In the latter case task_work_add() can no longer add the * new work after task_work_run() returns. */ void task_work_run(void) { struct task_struct *task = current; struct callback_head *work, *head, *next; for (;;) { /* * work->func() can do task_work_add(), do not set * work_exited unless the list is empty. */ do { work = READ_ONCE(task->task_works); head = !work && (task->flags & PF_EXITING) ? &work_exited : NULL; } while (cmpxchg(&task->task_works, work, head) != work); if (!work) break; /* * Synchronize with task_work_cancel(). It can't remove * the first entry == work, cmpxchg(task_works) should * fail, but it can play with *work and other entries. */ raw_spin_unlock_wait(&task->pi_lock); do { next = work->next; work->func(work); work = next; cond_resched(); } while (work); } } label'>space:mode:

author	Xin Long <lucien.xin@gmail.com>	2017-02-09 01:18:18 +0800
committer	David S. Miller <davem@davemloft.net>	2017-02-09 16:57:38 -0500
commit	a92ce1a42dde1caaee4afae67531e3e7acecf6e4 (patch)
tree	986627557298741d54a71074fd9d31ce1bfae810
parent	c56480a1e90261842f54f3a5a9ebc12d827f0c3e (diff)

sctp: implement sender-side procedures for SSN/TSN Reset Request Parameter

This patch is to implement Sender-Side Procedures for the SSN/TSN Reset Request Parameter descibed in rfc6525 section 5.1.4. It is also to add sockopt SCTP_RESET_ASSOC in rfc6525 section 6.3.3 for users. Signed-off-by: Xin Long <lucien.xin@gmail.com> Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>

Diffstat

-rw-r--r--

include/net/sctp/sctp.h

-rw-r--r--

include/uapi/linux/sctp.h

-rw-r--r--

net/sctp/socket.c

-rw-r--r--

net/sctp/stream.c

4 files changed, 71 insertions, 0 deletions