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authorAhmed S. Darwish <a.darwish@linutronix.de>2020-12-06 19:21:43 +0300
committerPeter Zijlstra <peterz@infradead.org>2020-12-09 19:08:49 +0300
commitcb262935a166bdef0ccfe6e2adffa00c0f2d038a (patch)
tree6b050dfa375b34a0434e8499a1909d3155d95912 /include/linux/seqlock.h
parent66bcfcdf89d00f2409f4b5da0f8c20c08318dc72 (diff)
downloadlinux-cb262935a166bdef0ccfe6e2adffa00c0f2d038a.tar.xz
seqlock: kernel-doc: Specify when preemption is automatically altered
The kernel-doc annotations for sequence counters write side functions are incomplete: they do not specify when preemption is automatically disabled and re-enabled. This has confused a number of call-site developers. Fix it. Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/CAHk-=wikhGExmprXgaW+MVXG1zsGpztBbVwOb23vetk41EtTBQ@mail.gmail.com
Diffstat (limited to 'include/linux/seqlock.h')
-rw-r--r--include/linux/seqlock.h17
1 files changed, 11 insertions, 6 deletions
diff --git a/include/linux/seqlock.h b/include/linux/seqlock.h
index 235cbc65fd71..2f7bb92b4c9e 100644
--- a/include/linux/seqlock.h
+++ b/include/linux/seqlock.h
@@ -456,6 +456,8 @@ static inline int do_read_seqcount_retry(const seqcount_t *s, unsigned start)
/**
* raw_write_seqcount_begin() - start a seqcount_t write section w/o lockdep
* @s: Pointer to seqcount_t or any of the seqcount_LOCKNAME_t variants
+ *
+ * Context: check write_seqcount_begin()
*/
#define raw_write_seqcount_begin(s) \
do { \
@@ -475,6 +477,8 @@ static inline void do_raw_write_seqcount_begin(seqcount_t *s)
/**
* raw_write_seqcount_end() - end a seqcount_t write section w/o lockdep
* @s: Pointer to seqcount_t or any of the seqcount_LOCKNAME_t variants
+ *
+ * Context: check write_seqcount_end()
*/
#define raw_write_seqcount_end(s) \
do { \
@@ -498,6 +502,7 @@ static inline void do_raw_write_seqcount_end(seqcount_t *s)
* @subclass: lockdep nesting level
*
* See Documentation/locking/lockdep-design.rst
+ * Context: check write_seqcount_begin()
*/
#define write_seqcount_begin_nested(s, subclass) \
do { \
@@ -519,11 +524,10 @@ static inline void do_write_seqcount_begin_nested(seqcount_t *s, int subclass)
* write_seqcount_begin() - start a seqcount_t write side critical section
* @s: Pointer to seqcount_t or any of the seqcount_LOCKNAME_t variants
*
- * write_seqcount_begin opens a write side critical section of the given
- * seqcount_t.
- *
- * Context: seqcount_t write side critical sections must be serialized and
- * non-preemptible. If readers can be invoked from hardirq or softirq
+ * Context: sequence counter write side sections must be serialized and
+ * non-preemptible. Preemption will be automatically disabled if and
+ * only if the seqcount write serialization lock is associated, and
+ * preemptible. If readers can be invoked from hardirq or softirq
* context, interrupts or bottom halves must be respectively disabled.
*/
#define write_seqcount_begin(s) \
@@ -545,7 +549,8 @@ static inline void do_write_seqcount_begin(seqcount_t *s)
* write_seqcount_end() - end a seqcount_t write side critical section
* @s: Pointer to seqcount_t or any of the seqcount_LOCKNAME_t variants
*
- * The write section must've been opened with write_seqcount_begin().
+ * Context: Preemption will be automatically re-enabled if and only if
+ * the seqcount write serialization lock is associated, and preemptible.
*/
#define write_seqcount_end(s) \
do { \