diff options
| author | Takashi Iwai <tiwai@suse.de> | 2013-11-08 16:45:38 +0100 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2013-11-08 16:45:38 +0100 |
| commit | a6bc732b5a96b5403c2637e85c350b95ec6591f3 (patch) | |
| tree | 4b1c3967cd1de42a5e36e567cbdd18e1f4e8446f /include/uapi | |
| parent | 9a22a8f558d09a83965d2bbe168294eb8ffb70e9 (diff) | |
| parent | dd212bd5bb8b15889821ef79213cdb5bd47c6f85 (diff) | |
Merge tag 'asoc-v3.13-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus
ASoC: Updates for v3.13
Some additional fixes for v3.13, the majority of which are removals and
downgrades of BUG()s from Takashi.
Diffstat (limited to 'include/uapi')
| -rw-r--r-- | include/uapi/linux/perf_event.h | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h index 009a655a5d35..2fc1602e23bb 100644 --- a/include/uapi/linux/perf_event.h +++ b/include/uapi/linux/perf_event.h @@ -456,13 +456,15 @@ struct perf_event_mmap_page { /* * Control data for the mmap() data buffer. * - * User-space reading the @data_head value should issue an rmb(), on - * SMP capable platforms, after reading this value -- see - * perf_event_wakeup(). + * User-space reading the @data_head value should issue an smp_rmb(), + * after reading this value. * * When the mapping is PROT_WRITE the @data_tail value should be - * written by userspace to reflect the last read data. In this case - * the kernel will not over-write unread data. + * written by userspace to reflect the last read data, after issueing + * an smp_mb() to separate the data read from the ->data_tail store. + * In this case the kernel will not over-write unread data. + * + * See perf_output_put_handle() for the data ordering. */ __u64 data_head; /* head in the data section */ __u64 data_tail; /* user-space written tail */ |