From: Chris Wilson Date: Tue, 19 Dec 2017 12:07:00 +0000 Subject: drm/syncobj: Stop reusing the same struct file for all syncobj -> fd Git-commit: e7cdf5c82f1773c3386b93bbcf13b9bfff29fa31 Patch-mainline: v4.15-rc5 References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166 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] Reported-by: Dave Airlie Signed-off-by: Chris Wilson Tested-by: Dave Airlie Reviewed-by: Daniel Vetter Signed-off-by: Dave Airlie Acked-by: Petr Tesarik --- drivers/gpu/drm/drm_syncobj.c | 77 +++++++++++++++--------------------------- 1 file changed, 29 insertions(+), 48 deletions(-) --- a/drivers/gpu/drm/drm_syncobj.c +++ b/drivers/gpu/drm/drm_syncobj.c @@ -369,40 +369,26 @@ static const struct file_operations drm_ .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; -} - int drm_syncobj_get_fd(struct drm_syncobj *syncobj, int *p_fd) { - int ret; + struct file *file; int fd; fd = get_unused_fd_flags(O_CLOEXEC); if (fd < 0) return fd; - if (!syncobj->file) { - ret = drm_syncobj_alloc_file(syncobj); - if (ret) { - put_unused_fd(fd); - return ret; - } + file = anon_inode_getfile("syncobj_file", + &drm_syncobj_file_fops, + syncobj, 0); + if (IS_ERR(file)) { + put_unused_fd(fd); + return PTR_ERR(file); } - fd_install(fd, syncobj->file); + + drm_syncobj_get(syncobj); + fd_install(fd, file); + *p_fd = fd; return 0; } @@ -422,31 +408,24 @@ static int drm_syncobj_handle_to_fd(stru 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); @@ -455,12 +434,14 @@ static int drm_syncobj_fd_to_handle(stru 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; } static int drm_syncobj_import_sync_file_fence(struct drm_file *file_private,