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authorChris Wilson <chris@chris-wilson.co.uk>2020-01-24 14:01:07 +0100
committerChris Wilson <chris@chris-wilson.co.uk>2020-01-24 18:41:34 +0100
commit7e13ad896484a0165a68197a2e64091ea28c9602 (patch)
treea20b339f718dd71ca66899a60a970230acc5963a /include/drm
parentdrm: Release filp before global lock (diff)
downloadlinux-7e13ad896484a0165a68197a2e64091ea28c9602.tar.xz
linux-7e13ad896484a0165a68197a2e64091ea28c9602.zip
drm: Avoid drm_global_mutex for simple inc/dec of dev->open_count
Since drm_global_mutex is a true global mutex across devices, we don't want to acquire it unless absolutely necessary. For maintaining the device local open_count, we can use atomic operations on the counter itself, except when making the transition to/from 0. Here, we tackle the easy portion of delaying acquiring the drm_global_mutex for the final release by using atomic_dec_and_mutex_lock(), leaving the global serialisation across the device opens. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Thomas Hellström (VMware) <thomas_os@shipmail.org> Reviewed-by: Thomas Hellström <thellstrom@vmware.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200124130107.125404-1-chris@chris-wilson.co.uk
Diffstat (limited to 'include/drm')
-rw-r--r--include/drm/drm_device.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/drm/drm_device.h b/include/drm/drm_device.h
index 1acfc3bbd3fb..bb60a949f416 100644
--- a/include/drm/drm_device.h
+++ b/include/drm/drm_device.h
@@ -144,7 +144,7 @@ struct drm_device {
* Usage counter for outstanding files open,
* protected by drm_global_mutex
*/
- int open_count;
+ atomic_t open_count;
/** @filelist_mutex: Protects @filelist. */
struct mutex filelist_mutex;