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| author | Chris Wilson <chris@chris-wilson.co.uk> | 2017-05-16 14:10:42 +0300 |
|---|---|---|
| committer | Gustavo Padovan <gustavo.padovan@collabora.com> | 2017-05-24 19:08:29 +0300 |
| commit | 71ebc9a3795818eab52e81bbcbdfae130ee35d9e (patch) | |
| tree | 471cdf0619cc75a44a992c0916beb498b3c894d9 /include | |
| parent | c16f291dee8b7dc28d4bd0f395ccecf3f898cd21 (diff) | |
| download | linux-71ebc9a3795818eab52e81bbcbdfae130ee35d9e.tar.xz | |
dma-buf/sync-file: Defer creation of sync_file->name
Constructing the name takes the majority of the time for allocating a
sync_file to wrap a fence, and the name is very rarely used (only via
the sync_file status user interface). To reduce the impact on the common
path (that of creating sync_file to pass around), defer the construction
of the name until it is first used.
v2: Update kerneldoc (kbuild test robot)
v3: sync_debug.c was peeking at the name
v4: Comment upon the potential race between two users of
sync_file_get_name() and claim that such a race is below the level of
notice. However, to prevent any future nuisance, use a global spinlock
to serialize the assignment of the name.
v5: Completely avoid the read/write race by only storing the name passed
in from the user inside sync_file->user_name and passing in a buffer to
dynamically construct the name otherwise.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Gustavo Padovan <gustavo@padovan.org>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Herrmann <dh.herrmann@gmail.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170516111042.24719-1-chris@chris-wilson.co.uk
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/sync_file.h | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/include/linux/sync_file.h b/include/linux/sync_file.h index d37beefdfbd5..5726107963b2 100644 --- a/include/linux/sync_file.h +++ b/include/linux/sync_file.h @@ -23,7 +23,6 @@ /** * struct sync_file - sync file to export to the userspace * @file: file representing this fence - * @name: name of sync_file. Useful for debugging * @sync_file_list: membership in global file list * @wq: wait queue for fence signaling * @fence: fence with the fences in the sync_file @@ -31,7 +30,14 @@ */ struct sync_file { struct file *file; - char name[32]; + /** + * @user_name: + * + * Name of the sync file provided by userspace, for merged fences. + * Otherwise generated through driver callbacks (in which case the + * entire array is 0). + */ + char user_name[32]; #ifdef CONFIG_DEBUG_FS struct list_head sync_file_list; #endif @@ -46,5 +52,6 @@ struct sync_file { struct sync_file *sync_file_create(struct dma_fence *fence); struct dma_fence *sync_file_get_fence(int fd); +char *sync_file_get_name(struct sync_file *sync_file, char *buf, int len); #endif /* _LINUX_SYNC_H */ |