diff options
| author |   Mauro Carvalho Chehab <mchehab@s-opensource.com> | 2016-08-08 07:30:25 -0300 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@s-opensource.com> | 2016-08-08 07:30:25 -0300 |
| commit | b6aa39228966e0d3f0bc3306be1892f87792903a (patch) | |
| tree | f2a61d1a72383e7e0e5f77043bf38c98eef2e0d4 /kernel/task_work.c | |
| parent | [media] cx231xx: reset pipe endpoint when it is stalled (diff) | |
| parent | Linux 4.8-rc1 (diff) | |
Merge tag 'v4.8-rc1' into patchwork
Linux 4.8-rc1
* tag 'v4.8-rc1': (6093 commits)
Linux 4.8-rc1
block: rename bio bi_rw to bi_opf
target: iblock_execute_sync_cache() should use bio_set_op_attrs()
mm: make __swap_writepage() use bio_set_op_attrs()
block/mm: make bdev_ops->rw_page() take a bool for read/write
fs: return EPERM on immutable inode
ramoops: use persistent_ram_free() instead of kfree() for freeing prz
ramoops: use DT reserved-memory bindings
NTB: ntb_hw_intel: use local variable pdev
NTB: ntb_hw_intel: show BAR size in debugfs info
ntb_test: Add a selftest script for the NTB subsystem
ntb_perf: clear link_is_up flag when the link goes down.
ntb_pingpong: Add a debugfs file to get the ping count
ntb_tool: Add link status and files to debugfs
ntb_tool: Postpone memory window initialization for the user
ntb_perf: Wait for link before running test
ntb_perf: Return results by reading the run file
ntb_perf: Improve thread handling to increase robustness
ntb_perf: Schedule based on time not on performance
ntb_transport: Check the number of spads the hardware supports
...
Diffstat (limited to 'kernel/task_work.c')
| -rw-r--r-- | kernel/task_work.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/kernel/task_work.c b/kernel/task_work.c index 6ab4842b00e8..d513051fcca2 100644 --- a/kernel/task_work.c +++ b/kernel/task_work.c @@ -29,7 +29,7 @@ task_work_add(struct task_struct *task, struct callback_head *work, bool notify) struct callback_head *head; do { - head = ACCESS_ONCE(task->task_works); + head = READ_ONCE(task->task_works); if (unlikely(head == &work_exited)) return -ESRCH; work->next = head; @@ -57,6 +57,9 @@ 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 @@ -64,8 +67,7 @@ task_work_cancel(struct task_struct *task, task_work_func_t func) * we raced with task_work_run(), *pprev == NULL/exited. */ raw_spin_lock_irqsave(&task->pi_lock, flags); - while ((work = ACCESS_ONCE(*pprev))) { - smp_read_barrier_depends(); + while ((work = lockless_dereference(*pprev))) { if (work->func != func) pprev = &work->next; else if (cmpxchg(pprev, work, work->next) == work) @@ -95,7 +97,7 @@ void task_work_run(void) * work_exited unless the list is empty. */ do { - work = ACCESS_ONCE(task->task_works); + work = READ_ONCE(task->task_works); head = !work && (task->flags & PF_EXITING) ? &work_exited : NULL; } while (cmpxchg(&task->task_works, work, head) != work); |