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| author | Takashi Iwai <tiwai@suse.de> | 2017-10-18 16:51:59 +0300 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2017-10-19 14:58:36 +0300 |
| commit | 9780ded39bef5d22a84bdc39112df93f70a58bdd (patch) | |
| tree | 312c860555df48fda2450d833a2cb1a7a7cd5b0e /sound/hda/local.h | |
| parent | 28d1d6d2f314ff395ff67565d1145742614b21c8 (diff) | |
| download | linux-9780ded39bef5d22a84bdc39112df93f70a58bdd.tar.xz | |
ALSA: hda: Avoid racy recreation of widget kobjects
The refresh of HD-audio widget sysfs kobjects via
snd_hdac_refresh_widget_sysfs() is slightly racy.
The driver recreates the whole tree from scratch after deleting the
whole. When CONFIG_DEBUG_KOBJECT_RELEASE option is used, kobject
release doesn't happen immediately but delayed, while the re-creation
of the same named kobject happens soon after invoking kobject_put().
This may end up with the conflicts of duplicated kobjects, as found in
the bug report below.
In this patch, we take another approach to refresh the tree: instead
of recreating the whole tree, just add the new nodes and delete the
non-existing nodes. Since the refresh happens only once at
initialization, no longer race would happen.
Along with the code change, merge snd_hdac_refresh_widget_sysfs() with
the existing snd_hdac_refresh_widgets() with an additional bool flag
for simplifying the code.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=197307
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/hda/local.h')
| -rw-r--r-- | sound/hda/local.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/sound/hda/local.h b/sound/hda/local.h index 0d5bb159d538..c586ea62d49e 100644 --- a/sound/hda/local.h +++ b/sound/hda/local.h @@ -28,6 +28,8 @@ static inline unsigned int get_wcaps_channels(u32 wcaps) extern const struct attribute_group *hdac_dev_attr_groups[]; int hda_widget_sysfs_init(struct hdac_device *codec); +int hda_widget_sysfs_reinit(struct hdac_device *codec, hda_nid_t start_nid, + int num_nodes); void hda_widget_sysfs_exit(struct hdac_device *codec); #endif /* __HDAC_LOCAL_H */ |