commit e7cdf5c82f1773c3386b93bbcf13b9bfff29fa31 upstream.
BR,
Jani.
On Mon, 26 Mar 2018, Jason Ekstrand <jason@xxxxxxxxxxxxxx> wrote:
> From: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
>
> The vk cts test:
> dEQP-VK.api.external.semaphore.opaque_fd.export_multiple_times_temporary
>
> triggers a lot of
> VFS: Close: file count is 0
>
> Dave pointed out that clearing the syncobj->file from
> drm_syncobj_file_release() was sufficient to silence the test, but that
> opens a can of worm since we assumed that the syncobj->file was never
> unset. Stop trying to reuse the same struct file for every fd pointing
> to the drm_syncobj, and allocate one file for each fd instead.
>
> v2: Fixup return handling of drm_syncobj_fd_to_handle
> v2.1: [airlied: fix possible syncobj ref race]
> v2.2: [jekstrand: back-port to 4.14]
>
> Reported-by: Dave Airlie <airlied@xxxxxxxxxx>
> Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> Tested-by: Dave Airlie <airlied@xxxxxxxxxx>
> Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
> Signed-off-by: Dave Airlie <airlied@xxxxxxxxxx>
> Signed-off-by: Jason Ekstrand <jason@xxxxxxxxxxxxxx>
> Tested-by: Clayton Craft <clayton.a.craft@xxxxxxxxx>
> ---
>
> The back-port from 4.15 to 4.14 was non-trivial. It'd be good if Chris and
> maybe Daniel could do a quick re-review.
>
> drivers/gpu/drm/drm_syncobj.c | 81 ++++++++++++++++---------------------------
> include/drm/drm_syncobj.h | 5 ---
> 2 files changed, 30 insertions(+), 56 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c
> index 0422b8c..7bcf570 100644
> --- a/drivers/gpu/drm/drm_syncobj.c
> +++ b/drivers/gpu/drm/drm_syncobj.c
> @@ -328,28 +328,11 @@ static const struct file_operations drm_syncobj_file_fops = {
> .release = drm_syncobj_file_release,
> };
>
> -static int drm_syncobj_alloc_file(struct drm_syncobj *syncobj)
> -{
> - struct file *file = anon_inode_getfile("syncobj_file",
> - &drm_syncobj_file_fops,
> - syncobj, 0);
> - if (IS_ERR(file))
> - return PTR_ERR(file);
> -
> - drm_syncobj_get(syncobj);
> - if (cmpxchg(&syncobj->file, NULL, file)) {
> - /* lost the race */
> - fput(file);
> - }
> -
> - return 0;
> -}
> -
> static int drm_syncobj_handle_to_fd(struct drm_file *file_private,
> u32 handle, int *p_fd)
> {
> struct drm_syncobj *syncobj = drm_syncobj_find(file_private, handle);
> - int ret;
> + struct file *file;
> int fd;
>
> if (!syncobj)
> @@ -361,46 +344,40 @@ static int drm_syncobj_handle_to_fd(struct drm_file *file_private,
> return fd;
> }
>
> - if (!syncobj->file) {
> - ret = drm_syncobj_alloc_file(syncobj);
> - if (ret)
> - goto out_put_fd;
> + file = anon_inode_getfile("syncobj_file",
> + &drm_syncobj_file_fops,
> + syncobj, 0);
> + if (IS_ERR(file)) {
> + put_unused_fd(fd);
> + drm_syncobj_put(syncobj);
> + return PTR_ERR(file);
> }
> - fd_install(fd, syncobj->file);
> - drm_syncobj_put(syncobj);
> +
> + drm_syncobj_get(syncobj);
> + fd_install(fd, file);
> +
> *p_fd = fd;
> return 0;
> -out_put_fd:
> - put_unused_fd(fd);
> - drm_syncobj_put(syncobj);
> - return ret;
> }
>
> -static struct drm_syncobj *drm_syncobj_fdget(int fd)
> -{
> - struct file *file = fget(fd);
> -
> - if (!file)
> - return NULL;
> - if (file->f_op != &drm_syncobj_file_fops)
> - goto err;
> -
> - return file->private_data;
> -err:
> - fput(file);
> - return NULL;
> -};
> -
> static int drm_syncobj_fd_to_handle(struct drm_file *file_private,
> int fd, u32 *handle)
> {
> - struct drm_syncobj *syncobj = drm_syncobj_fdget(fd);
> + struct drm_syncobj *syncobj;
> + struct file *file;
> int ret;
>
> - if (!syncobj)
> + file = fget(fd);
> + if (!file)
> + return -EINVAL;
> +
> + if (file->f_op != &drm_syncobj_file_fops) {
> + fput(file);
> return -EINVAL;
> + }
>
> /* take a reference to put in the idr */
> + syncobj = file->private_data;
> drm_syncobj_get(syncobj);
>
> idr_preload(GFP_KERNEL);
> @@ -409,12 +386,14 @@ static int drm_syncobj_fd_to_handle(struct drm_file *file_private,
> spin_unlock(&file_private->syncobj_table_lock);
> idr_preload_end();
>
> - if (ret < 0) {
> - fput(syncobj->file);
> - return ret;
> - }
> - *handle = ret;
> - return 0;
> + if (ret > 0) {
> + *handle = ret;
> + ret = 0;
> + } else
> + drm_syncobj_put(syncobj);
> +
> + fput(file);
> + return ret;
> }
>
> int drm_syncobj_import_sync_file_fence(struct drm_file *file_private,
> diff --git a/include/drm/drm_syncobj.h b/include/drm/drm_syncobj.h
> index c00fee5..6d45aae 100644
> --- a/include/drm/drm_syncobj.h
> +++ b/include/drm/drm_syncobj.h
> @@ -60,11 +60,6 @@ struct drm_syncobj {
> * locks cb_list and write-locks fence.
> */
> spinlock_t lock;
> - /**
> - * @file:
> - * a file backing for this syncobj.
> - */
> - struct file *file;
> };
>
> typedef void (*drm_syncobj_func_t)(struct drm_syncobj *syncobj,
--
Jani Nikula, Intel Open Source Technology Center