Le 16/09/2024 à 16:35, Tvrtko Ursulin a écrit :
On 16/09/2024 14:32, Pierre-Eric Pelloux-Prayer wrote:Giving the opportunity to userspace to associate a free-form name with a drm_file struct is helpful for tracking and debugging. This is similar to the existing DMA_BUF_SET_NAME ioctl. Access to name is protected by a mutex, and the 'clients' debugfs file has been updated to print it. Userspace MR to use this ioctl: https://gitlab.freedesktop.org/virgl/virglrenderer/-/merge_requests/1428 The string passed by userspace is filtered a bit, to avoid messing output when it's going to be printed (in dmesg, fdinfo, etc): * all chars failing isgraph() are replaced by '-' * if a 0-length string is passed the name is cleared Signed-off-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@xxxxxxx> --- drivers/gpu/drm/drm_debugfs.c | 12 ++++++---- drivers/gpu/drm/drm_file.c | 5 +++++ drivers/gpu/drm/drm_ioctl.c | 42 +++++++++++++++++++++++++++++++++++ include/drm/drm_file.h | 9 ++++++++ include/uapi/drm/drm.h | 14 ++++++++++++ 5 files changed, 78 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/drm_debugfs.c b/drivers/gpu/drm/drm_debugfs.c index 6b239a24f1df..b7492225ae88 100644 --- a/drivers/gpu/drm/drm_debugfs.c +++ b/drivers/gpu/drm/drm_debugfs.c @@ -78,12 +78,13 @@ static int drm_clients_info(struct seq_file *m, void *data) kuid_t uid; seq_printf(m, - "%20s %5s %3s master a %5s %10s\n", + "%20s %5s %3s master a %5s %10s %20s\n", "command", "tgid", "dev", "uid", - "magic"); + "magic", + "name"); /* dev->filelist is sorted youngest first, but we want to present * oldest first (i.e. kernel, servers, clients), so walk backwardss. @@ -94,19 +95,22 @@ static int drm_clients_info(struct seq_file *m, void *data) struct task_struct *task; struct pid *pid; + mutex_lock(&priv->name_lock); rcu_read_lock(); /* Locks priv->pid and pid_task()->comm! */ pid = rcu_dereference(priv->pid); task = pid_task(pid, PIDTYPE_TGID); uid = task ? __task_cred(task)->euid : GLOBAL_ROOT_UID; - seq_printf(m, "%20s %5d %3d %c %c %5d %10u\n", + seq_printf(m, "%20s %5d %3d %c %c %5d %10u %20s\n", task ? task->comm : "<unknown>", pid_vnr(pid), priv->minor->index, is_current_master ? 'y' : 'n', priv->authenticated ? 'y' : 'n', from_kuid_munged(seq_user_ns(m), uid), - priv->magic); + priv->magic, + priv->name ? priv->name : ""); rcu_read_unlock(); + mutex_unlock(&priv->name_lock); } mutex_unlock(&dev->filelist_mutex); return 0; diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c index 01fde94fe2a9..e9dd0e90a1f9 100644 --- a/drivers/gpu/drm/drm_file.c +++ b/drivers/gpu/drm/drm_file.c @@ -158,6 +158,7 @@ struct drm_file *drm_file_alloc(struct drm_minor *minor) spin_lock_init(&file->master_lookup_lock); mutex_init(&file->event_read_lock); + mutex_init(&file->name_lock); if (drm_core_check_feature(dev, DRIVER_GEM)) drm_gem_open(dev, file); @@ -259,6 +260,10 @@ void drm_file_free(struct drm_file *file) WARN_ON(!list_empty(&file->event_list)); put_pid(rcu_access_pointer(file->pid)); + + mutex_destroy(&file->name_lock); + kfree(file->name); + kfree(file); } diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c index 51f39912866f..b7d7bede0ab3 100644 --- a/drivers/gpu/drm/drm_ioctl.c +++ b/drivers/gpu/drm/drm_ioctl.c @@ -540,6 +540,46 @@ int drm_version(struct drm_device *dev, void *data, return err; } +static int drm_set_name(struct drm_device *dev, void *data, + struct drm_file *file_priv) +{ + struct drm_set_name *name = data; + void *user_ptr;__user as kernel test robot reminds us.
Fixed in v3.
+ char *new_name; + size_t i, len; + + if (name->name_len >= NAME_MAX) + return -EINVAL;Maybe it is a bit unsubstantiated, but I am leaning towards a feeling of lets define own smaller limit, like dma-buf does. If 32 is deemed too restrictive make it larger but 255 feels unnecessary. But I don't feel to strongly about this so if people insist we need the names this long then so be it.
v3 has "#define DRM_NAME_MAX_LEN 64".
+ + user_ptr = u64_to_user_ptr(name->name); + + new_name = memdup_user_nul(user_ptr, name->name_len); +Nit: I'd zap this blank line since it is breaking a logical group.
Done in v3.
+ if (IS_ERR(new_name)) + return PTR_ERR(new_name); + + /* Filter out control char / spaces / new lines etc in the name + * since it's going to be used in dmesg or fdinfo's output. + */Nit: Preferred kernel style for multi-line comments is: /* * Comment */ Unless amdgpu preferes to stick with the above. I think I've seen both used so don't know.
Done in v3.
+ len = strlen(new_name);Made me think if it is worth cross-checking against name->name_len and reject on mismatch? Probably yes.
Added to v3.
+ for (i = 0; i < len; i++) { + if (!isgraph(new_name[i])) + new_name[i] = '-'; + }For completeness, alternative is to -EINVAL it. I have no strong opinions either way.
For now I've kept the filtering approach and added a comment about it in include/uapi/drm/drm.h.
+ + mutex_lock(&file_priv->name_lock); + kfree(file_priv->name); + if (len > 0) { + file_priv->name = new_name; + } else { + kfree(new_name); + file_priv->name = NULL;FWIW you could not bother allocating new_file in this case.
I've kept the code as-is, I kind of prefer it done the way it is. Thanks for your review, Pierre-Eric
Regards, Tvrtko+ } + mutex_unlock(&file_priv->name_lock); + + return 0; +} + static int drm_ioctl_permit(u32 flags, struct drm_file *file_priv) { /* ROOT_ONLY is only for CAP_SYS_ADMIN */ @@ -610,6 +650,8 @@ static const struct drm_ioctl_desc drm_ioctls[] = { DRM_IOCTL_DEF(DRM_IOCTL_PRIME_HANDLE_TO_FD, drm_prime_handle_to_fd_ioctl, DRM_RENDER_ALLOW), DRM_IOCTL_DEF(DRM_IOCTL_PRIME_FD_TO_HANDLE, drm_prime_fd_to_handle_ioctl, DRM_RENDER_ALLOW), + DRM_IOCTL_DEF(DRM_IOCTL_SET_NAME, drm_set_name, DRM_RENDER_ALLOW), + DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETPLANERESOURCES, drm_mode_getplane_res, 0), DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETCRTC, drm_mode_getcrtc, 0), DRM_IOCTL_DEF(DRM_IOCTL_MODE_SETCRTC, drm_mode_setcrtc, DRM_MASTER), diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h index 8c0030c77308..df26eee8f79c 100644 --- a/include/drm/drm_file.h +++ b/include/drm/drm_file.h @@ -388,6 +388,15 @@ struct drm_file { * Per-file buffer caches used by the PRIME buffer sharing code. */ struct drm_prime_file_private prime; + + /** + * @name: + * + * Userspace-provided name; useful for accounting and debugging. + */ + const char *name; + /** @name_lock: Protects @name. */ + struct mutex name_lock; }; /** diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h index 16122819edfe..fc62bb21f79e 100644 --- a/include/uapi/drm/drm.h +++ b/include/uapi/drm/drm.h @@ -1024,6 +1024,12 @@ struct drm_crtc_queue_sequence { __u64 user_data; /* user data passed to event */ }; +struct drm_set_name { + __u64 name_len; + __u64 name; +}; + + #if defined(__cplusplus) } #endif @@ -1288,6 +1294,14 @@ extern "C" { */ #define DRM_IOCTL_MODE_CLOSEFB DRM_IOWR(0xD0, struct drm_mode_closefb) +/** + * DRM_IOCTL_SET_NAME - Attach a name to a drm_file + * + * This ioctl is similar to DMA_BUF_SET_NAME - it allows for easier tracking + * and debugging. + */ +#define DRM_IOCTL_SET_NAME DRM_IOWR(0xD1, struct drm_set_name) + /* * Device specific ioctls should only be in their respective headers * The device specific ioctl range is from 0x40 to 0x9f.
