Re: [PATCH] drm: make drm_get_format_name thread-safe
From: Jani Nikula
Date: Mon Aug 15 2016 - 05:54:14 EST
On Mon, 15 Aug 2016, Eric Engestrom <eric@xxxxxxxxxxxx> wrote:
> Signed-off-by: Eric Engestrom <eric@xxxxxxxxxxxx>
> ---
>
> I moved the main bits to be the first diffs, shouldn't affect anything
> when applying the patch, but I wanted to ask:
> I don't like the hard-coded `32` the appears in both kmalloc() and
> snprintf(), what do you think? If you don't like it either, what would
> you suggest? Should I #define it?
>
> Second question is about the patch mail itself: should I send this kind
> of patch separated by module, with a note requesting them to be squashed
> when applying? It has to land as a single patch, but for review it might
> be easier if people only see the bits they each care about, as well as
> to collect ack's/r-b's.
>
> Cheers,
> Eric
>
> ---
> drivers/gpu/drm/amd/amdgpu/dce_v10_0.c | 6 ++--
> drivers/gpu/drm/amd/amdgpu/dce_v11_0.c | 6 ++--
> drivers/gpu/drm/amd/amdgpu/dce_v8_0.c | 6 ++--
> drivers/gpu/drm/drm_atomic.c | 5 ++--
> drivers/gpu/drm/drm_crtc.c | 21 ++++++++-----
> drivers/gpu/drm/drm_fourcc.c | 17 ++++++-----
> drivers/gpu/drm/hisilicon/kirin/kirin_drm_ade.c | 6 ++--
> drivers/gpu/drm/i915/i915_debugfs.c | 11 ++++++-
> drivers/gpu/drm/i915/intel_atomic_plane.c | 6 ++--
> drivers/gpu/drm/i915/intel_display.c | 39 ++++++++++++++++---------
> drivers/gpu/drm/radeon/atombios_crtc.c | 12 +++++---
> include/drm/drm_fourcc.h | 2 +-
> 12 files changed, 89 insertions(+), 48 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_fourcc.c b/drivers/gpu/drm/drm_fourcc.c
> index 0645c85..38216a1 100644
> --- a/drivers/gpu/drm/drm_fourcc.c
> +++ b/drivers/gpu/drm/drm_fourcc.c
> @@ -39,16 +39,14 @@ static char printable_char(int c)
> * drm_get_format_name - return a string for drm fourcc format
> * @format: format to compute name of
> *
> - * Note that the buffer used by this function is globally shared and owned by
> - * the function itself.
> - *
> - * FIXME: This isn't really multithreading safe.
> + * Note that the buffer returned by this function is owned by the caller
> + * and will need to be freed.
> */
> const char *drm_get_format_name(uint32_t format)
I find it surprising that a function that allocates a buffer returns a
const pointer. Some userspace libraries have conventions about the
ownership based on constness.
(I also find it suprising that kfree() takes a const pointer; arguably
that call changes the memory.)
Is there precedent for this?
BR,
Jani.
> {
> - static char buf[32];
> + char *buf = kmalloc(32, GFP_KERNEL);
>
> - snprintf(buf, sizeof(buf),
> + snprintf(buf, 32,
> "%c%c%c%c %s-endian (0x%08x)",
> printable_char(format & 0xff),
> printable_char((format >> 8) & 0xff),
> @@ -73,6 +71,8 @@ EXPORT_SYMBOL(drm_get_format_name);
> void drm_fb_get_bpp_depth(uint32_t format, unsigned int *depth,
> int *bpp)
> {
> + const char *format_name;
> +
> switch (format) {
> case DRM_FORMAT_C8:
> case DRM_FORMAT_RGB332:
> @@ -127,8 +127,9 @@ void drm_fb_get_bpp_depth(uint32_t format, unsigned int *depth,
> *bpp = 32;
> break;
> default:
> - DRM_DEBUG_KMS("unsupported pixel format %s\n",
> - drm_get_format_name(format));
> + format_name = drm_get_format_name(format);
> + DRM_DEBUG_KMS("unsupported pixel format %s\n", format_name);
> + kfree(format_name);
> *depth = 0;
> *bpp = 0;
> break;
> diff --git a/include/drm/drm_fourcc.h b/include/drm/drm_fourcc.h
> index 7f90a39..030d22d 100644
> --- a/include/drm/drm_fourcc.h
> +++ b/include/drm/drm_fourcc.h
> @@ -32,6 +32,6 @@ int drm_format_horz_chroma_subsampling(uint32_t format);
> int drm_format_vert_chroma_subsampling(uint32_t format);
> int drm_format_plane_width(int width, uint32_t format, int plane);
> int drm_format_plane_height(int height, uint32_t format, int plane);
> -const char *drm_get_format_name(uint32_t format);
> +const char *drm_get_format_name(uint32_t format) __malloc;
>
> #endif /* __DRM_FOURCC_H__ */
> diff --git a/drivers/gpu/drm/amd/amdgpu/dce_v10_0.c b/drivers/gpu/drm/amd/amdgpu/dce_v10_0.c
> index c1b04e9..0bf8959 100644
> --- a/drivers/gpu/drm/amd/amdgpu/dce_v10_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/dce_v10_0.c
> @@ -2071,6 +2071,7 @@ static int dce_v10_0_crtc_do_set_base(struct drm_crtc *crtc,
> u32 tmp, viewport_w, viewport_h;
> int r;
> bool bypass_lut = false;
> + const char *format_name;
>
> /* no fb bound */
> if (!atomic && !crtc->primary->fb) {
> @@ -2182,8 +2183,9 @@ static int dce_v10_0_crtc_do_set_base(struct drm_crtc *crtc,
> bypass_lut = true;
> break;
> default:
> - DRM_ERROR("Unsupported screen format %s\n",
> - drm_get_format_name(target_fb->pixel_format));
> + format_name = drm_get_format_name(target_fb->pixel_format);
> + DRM_ERROR("Unsupported screen format %s\n", format_name);
> + kfree(format_name);
> return -EINVAL;
> }
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/dce_v11_0.c b/drivers/gpu/drm/amd/amdgpu/dce_v11_0.c
> index d4bf133..1558a97 100644
> --- a/drivers/gpu/drm/amd/amdgpu/dce_v11_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/dce_v11_0.c
> @@ -2046,6 +2046,7 @@ static int dce_v11_0_crtc_do_set_base(struct drm_crtc *crtc,
> u32 tmp, viewport_w, viewport_h;
> int r;
> bool bypass_lut = false;
> + const char *format_name;
>
> /* no fb bound */
> if (!atomic && !crtc->primary->fb) {
> @@ -2157,8 +2158,9 @@ static int dce_v11_0_crtc_do_set_base(struct drm_crtc *crtc,
> bypass_lut = true;
> break;
> default:
> - DRM_ERROR("Unsupported screen format %s\n",
> - drm_get_format_name(target_fb->pixel_format));
> + format_name = drm_get_format_name(target_fb->pixel_format);
> + DRM_ERROR("Unsupported screen format %s\n", format_name);
> + kfree(format_name);
> return -EINVAL;
> }
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/dce_v8_0.c b/drivers/gpu/drm/amd/amdgpu/dce_v8_0.c
> index 4fdfab1..71a0375 100644
> --- a/drivers/gpu/drm/amd/amdgpu/dce_v8_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/dce_v8_0.c
> @@ -1952,6 +1952,7 @@ static int dce_v8_0_crtc_do_set_base(struct drm_crtc *crtc,
> u32 viewport_w, viewport_h;
> int r;
> bool bypass_lut = false;
> + const char *format_name;
>
> /* no fb bound */
> if (!atomic && !crtc->primary->fb) {
> @@ -2056,8 +2057,9 @@ static int dce_v8_0_crtc_do_set_base(struct drm_crtc *crtc,
> bypass_lut = true;
> break;
> default:
> - DRM_ERROR("Unsupported screen format %s\n",
> - drm_get_format_name(target_fb->pixel_format));
> + format_name = drm_get_format_name(target_fb->pixel_format);
> + DRM_ERROR("Unsupported screen format %s\n", format_name);
> + kfree(format_name);
> return -EINVAL;
> }
>
> diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
> index fa39307..087391f 100644
> --- a/drivers/gpu/drm/drm_atomic.c
> +++ b/drivers/gpu/drm/drm_atomic.c
> @@ -837,8 +837,9 @@ static int drm_atomic_plane_check(struct drm_plane *plane,
> /* Check whether this plane supports the fb pixel format. */
> ret = drm_plane_check_pixel_format(plane, state->fb->pixel_format);
> if (ret) {
> - DRM_DEBUG_ATOMIC("Invalid pixel format %s\n",
> - drm_get_format_name(state->fb->pixel_format));
> + const char *format_name = drm_get_format_name(state->fb->pixel_format);
> + DRM_DEBUG_ATOMIC("Invalid pixel format %s\n", format_name);
> + kfree(format_name);
> return ret;
> }
>
> diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
> index b1dbb60..7da5d33 100644
> --- a/drivers/gpu/drm/drm_crtc.c
> +++ b/drivers/gpu/drm/drm_crtc.c
> @@ -2592,8 +2592,9 @@ static int __setplane_internal(struct drm_plane *plane,
> /* Check whether this plane supports the fb pixel format. */
> ret = drm_plane_check_pixel_format(plane, fb->pixel_format);
> if (ret) {
> - DRM_DEBUG_KMS("Invalid pixel format %s\n",
> - drm_get_format_name(fb->pixel_format));
> + const char *format_name = drm_get_format_name(fb->pixel_format);
> + DRM_DEBUG_KMS("Invalid pixel format %s\n", format_name);
> + kfree(format_name);
> goto out;
> }
>
> @@ -2902,8 +2903,9 @@ int drm_mode_setcrtc(struct drm_device *dev, void *data,
> ret = drm_plane_check_pixel_format(crtc->primary,
> fb->pixel_format);
> if (ret) {
> - DRM_DEBUG_KMS("Invalid pixel format %s\n",
> - drm_get_format_name(fb->pixel_format));
> + const char *format_name = drm_get_format_name(fb->pixel_format);
> + DRM_DEBUG_KMS("Invalid pixel format %s\n", format_name);
> + kfree(format_name);
> goto out;
> }
> }
> @@ -3279,6 +3281,7 @@ int drm_mode_addfb(struct drm_device *dev,
> static int format_check(const struct drm_mode_fb_cmd2 *r)
> {
> uint32_t format = r->pixel_format & ~DRM_FORMAT_BIG_ENDIAN;
> + const char *format_name;
>
> switch (format) {
> case DRM_FORMAT_C8:
> @@ -3343,8 +3346,9 @@ static int format_check(const struct drm_mode_fb_cmd2 *r)
> case DRM_FORMAT_YVU444:
> return 0;
> default:
> - DRM_DEBUG_KMS("invalid pixel format %s\n",
> - drm_get_format_name(r->pixel_format));
> + format_name = drm_get_format_name(r->pixel_format);
> + DRM_DEBUG_KMS("invalid pixel format %s\n", format_name);
> + kfree(format_name);
> return -EINVAL;
> }
> }
> @@ -3355,8 +3359,9 @@ static int framebuffer_check(const struct drm_mode_fb_cmd2 *r)
>
> ret = format_check(r);
> if (ret) {
> - DRM_DEBUG_KMS("bad framebuffer format %s\n",
> - drm_get_format_name(r->pixel_format));
> + const char *format_name = drm_get_format_name(r->pixel_format);
> + DRM_DEBUG_KMS("bad framebuffer format %s\n", format_name);
> + kfree(format_name);
> return ret;
> }
>
> diff --git a/drivers/gpu/drm/hisilicon/kirin/kirin_drm_ade.c b/drivers/gpu/drm/hisilicon/kirin/kirin_drm_ade.c
> index c3707d4..ac7fa02 100644
> --- a/drivers/gpu/drm/hisilicon/kirin/kirin_drm_ade.c
> +++ b/drivers/gpu/drm/hisilicon/kirin/kirin_drm_ade.c
> @@ -608,15 +608,17 @@ static void ade_rdma_set(void __iomem *base, struct drm_framebuffer *fb,
> u32 ch, u32 y, u32 in_h, u32 fmt)
> {
> struct drm_gem_cma_object *obj = drm_fb_cma_get_gem_obj(fb, 0);
> + const char *format_name;
> u32 reg_ctrl, reg_addr, reg_size, reg_stride, reg_space, reg_en;
> u32 stride = fb->pitches[0];
> u32 addr = (u32)obj->paddr + y * stride;
>
> DRM_DEBUG_DRIVER("rdma%d: (y=%d, height=%d), stride=%d, paddr=0x%x\n",
> ch + 1, y, in_h, stride, (u32)obj->paddr);
> + format_name = drm_get_format_name(fb->pixel_format);
> DRM_DEBUG_DRIVER("addr=0x%x, fb:%dx%d, pixel_format=%d(%s)\n",
> - addr, fb->width, fb->height, fmt,
> - drm_get_format_name(fb->pixel_format));
> + addr, fb->width, fb->height, fmt, format_name);
> + kfree(format_name);
>
> /* get reg offset */
> reg_ctrl = RD_CH_CTRL(ch);
> diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
> index 844fea7..904720b 100644
> --- a/drivers/gpu/drm/i915/i915_debugfs.c
> +++ b/drivers/gpu/drm/i915/i915_debugfs.c
> @@ -3109,6 +3109,7 @@ static void intel_plane_info(struct seq_file *m, struct intel_crtc *intel_crtc)
> for_each_intel_plane_on_crtc(dev, intel_crtc, intel_plane) {
> struct drm_plane_state *state;
> struct drm_plane *plane = &intel_plane->base;
> + const char *format_name;
>
> if (!plane->state) {
> seq_puts(m, "plane->state is NULL!\n");
> @@ -3117,6 +3118,12 @@ static void intel_plane_info(struct seq_file *m, struct intel_crtc *intel_crtc)
>
> state = plane->state;
>
> + if (state->fb) {
> + format_name = drm_get_format_name(state->fb->pixel_format);
> + } else {
> + format_name = kstrdup("N/A", GFP_KERNEL);
> + }
> +
> seq_printf(m, "\t--Plane id %d: type=%s, crtc_pos=%4dx%4d, crtc_size=%4dx%4d, src_pos=%d.%04ux%d.%04u, src_size=%d.%04ux%d.%04u, format=%s, rotation=%s\n",
> plane->base.id,
> plane_type(intel_plane->base.type),
> @@ -3130,8 +3137,10 @@ static void intel_plane_info(struct seq_file *m, struct intel_crtc *intel_crtc)
> ((state->src_w & 0xffff) * 15625) >> 10,
> (state->src_h >> 16),
> ((state->src_h & 0xffff) * 15625) >> 10,
> - state->fb ? drm_get_format_name(state->fb->pixel_format) : "N/A",
> + format_name,
> plane_rotation(state->rotation));
> +
> + kfree(format_name);
> }
> }
>
> diff --git a/drivers/gpu/drm/i915/intel_atomic_plane.c b/drivers/gpu/drm/i915/intel_atomic_plane.c
> index 7de7721..e06131a 100644
> --- a/drivers/gpu/drm/i915/intel_atomic_plane.c
> +++ b/drivers/gpu/drm/i915/intel_atomic_plane.c
> @@ -157,6 +157,7 @@ static int intel_plane_atomic_check(struct drm_plane *plane,
> crtc_state->base.enable ? crtc_state->pipe_src_h : 0;
>
> if (state->fb && intel_rotation_90_or_270(state->rotation)) {
> + const char *format_name;
> if (!(state->fb->modifier[0] == I915_FORMAT_MOD_Y_TILED ||
> state->fb->modifier[0] == I915_FORMAT_MOD_Yf_TILED)) {
> DRM_DEBUG_KMS("Y/Yf tiling required for 90/270!\n");
> @@ -171,8 +172,9 @@ static int intel_plane_atomic_check(struct drm_plane *plane,
> switch (state->fb->pixel_format) {
> case DRM_FORMAT_C8:
> case DRM_FORMAT_RGB565:
> - DRM_DEBUG_KMS("Unsupported pixel format %s for 90/270!\n",
> - drm_get_format_name(state->fb->pixel_format));
> + format_name = drm_get_format_name(state->fb->pixel_format);
> + DRM_DEBUG_KMS("Unsupported pixel format %s for 90/270!\n", format_name);
> + kfree(format_name);
> return -EINVAL;
>
> default:
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index c457eed..071399b 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -12282,6 +12282,7 @@ static void intel_dump_pipe_config(struct intel_crtc *crtc,
>
> DRM_DEBUG_KMS("planes on this crtc\n");
> list_for_each_entry(plane, &dev->mode_config.plane_list, head) {
> + const char *format_name;
> intel_plane = to_intel_plane(plane);
> if (intel_plane->pipe != crtc->pipe)
> continue;
> @@ -12294,11 +12295,12 @@ static void intel_dump_pipe_config(struct intel_crtc *crtc,
> continue;
> }
>
> + format_name = drm_get_format_name(fb->pixel_format);
> +
> DRM_DEBUG_KMS("[PLANE:%d:%s] enabled",
> plane->base.id, plane->name);
> DRM_DEBUG_KMS("\tFB:%d, fb = %ux%u format = %s",
> - fb->base.id, fb->width, fb->height,
> - drm_get_format_name(fb->pixel_format));
> + fb->base.id, fb->width, fb->height, format_name);
> DRM_DEBUG_KMS("\tscaler:%d src %dx%d+%d+%d dst %dx%d+%d+%d\n",
> state->scaler_id,
> state->src.x1 >> 16, state->src.y1 >> 16,
> @@ -12307,6 +12309,8 @@ static void intel_dump_pipe_config(struct intel_crtc *crtc,
> state->dst.x1, state->dst.y1,
> drm_rect_width(&state->dst),
> drm_rect_height(&state->dst));
> +
> + kfree(format_name);
> }
> }
>
> @@ -14936,6 +14940,7 @@ static int intel_framebuffer_init(struct drm_device *dev,
> unsigned int aligned_height;
> int ret;
> u32 pitch_limit, stride_alignment;
> + const char *format_name;
>
> WARN_ON(!mutex_is_locked(&dev->struct_mutex));
>
> @@ -15009,16 +15014,18 @@ static int intel_framebuffer_init(struct drm_device *dev,
> break;
> case DRM_FORMAT_XRGB1555:
> if (INTEL_INFO(dev)->gen > 3) {
> - DRM_DEBUG("unsupported pixel format: %s\n",
> - drm_get_format_name(mode_cmd->pixel_format));
> + format_name = drm_get_format_name(mode_cmd->pixel_format);
> + DRM_DEBUG("unsupported pixel format: %s\n", format_name);
> + kfree(format_name);
> return -EINVAL;
> }
> break;
> case DRM_FORMAT_ABGR8888:
> if (!IS_VALLEYVIEW(dev) && !IS_CHERRYVIEW(dev) &&
> INTEL_INFO(dev)->gen < 9) {
> - DRM_DEBUG("unsupported pixel format: %s\n",
> - drm_get_format_name(mode_cmd->pixel_format));
> + format_name = drm_get_format_name(mode_cmd->pixel_format);
> + DRM_DEBUG("unsupported pixel format: %s\n", format_name);
> + kfree(format_name);
> return -EINVAL;
> }
> break;
> @@ -15026,15 +15033,17 @@ static int intel_framebuffer_init(struct drm_device *dev,
> case DRM_FORMAT_XRGB2101010:
> case DRM_FORMAT_XBGR2101010:
> if (INTEL_INFO(dev)->gen < 4) {
> - DRM_DEBUG("unsupported pixel format: %s\n",
> - drm_get_format_name(mode_cmd->pixel_format));
> + format_name = drm_get_format_name(mode_cmd->pixel_format);
> + DRM_DEBUG("unsupported pixel format: %s\n", format_name);
> + kfree(format_name);
> return -EINVAL;
> }
> break;
> case DRM_FORMAT_ABGR2101010:
> if (!IS_VALLEYVIEW(dev) && !IS_CHERRYVIEW(dev)) {
> - DRM_DEBUG("unsupported pixel format: %s\n",
> - drm_get_format_name(mode_cmd->pixel_format));
> + format_name = drm_get_format_name(mode_cmd->pixel_format);
> + DRM_DEBUG("unsupported pixel format: %s\n", format_name);
> + kfree(format_name);
> return -EINVAL;
> }
> break;
> @@ -15043,14 +15052,16 @@ static int intel_framebuffer_init(struct drm_device *dev,
> case DRM_FORMAT_YVYU:
> case DRM_FORMAT_VYUY:
> if (INTEL_INFO(dev)->gen < 5) {
> - DRM_DEBUG("unsupported pixel format: %s\n",
> - drm_get_format_name(mode_cmd->pixel_format));
> + format_name = drm_get_format_name(mode_cmd->pixel_format);
> + DRM_DEBUG("unsupported pixel format: %s\n", format_name);
> + kfree(format_name);
> return -EINVAL;
> }
> break;
> default:
> - DRM_DEBUG("unsupported pixel format: %s\n",
> - drm_get_format_name(mode_cmd->pixel_format));
> + format_name = drm_get_format_name(mode_cmd->pixel_format);
> + DRM_DEBUG("unsupported pixel format: %s\n", format_name);
> + kfree(format_name);
> return -EINVAL;
> }
>
> diff --git a/drivers/gpu/drm/radeon/atombios_crtc.c b/drivers/gpu/drm/radeon/atombios_crtc.c
> index a97abc8..981ca3f 100644
> --- a/drivers/gpu/drm/radeon/atombios_crtc.c
> +++ b/drivers/gpu/drm/radeon/atombios_crtc.c
> @@ -1154,6 +1154,7 @@ static int dce4_crtc_do_set_base(struct drm_crtc *crtc,
> u32 tmp, viewport_w, viewport_h;
> int r;
> bool bypass_lut = false;
> + const char *format_name;
>
> /* no fb bound */
> if (!atomic && !crtc->primary->fb) {
> @@ -1257,8 +1258,9 @@ static int dce4_crtc_do_set_base(struct drm_crtc *crtc,
> bypass_lut = true;
> break;
> default:
> - DRM_ERROR("Unsupported screen format %s\n",
> - drm_get_format_name(target_fb->pixel_format));
> + format_name = drm_get_format_name(target_fb->pixel_format);
> + DRM_ERROR("Unsupported screen format %s\n", format_name);
> + kfree(format_name);
> return -EINVAL;
> }
>
> @@ -1469,6 +1471,7 @@ static int avivo_crtc_do_set_base(struct drm_crtc *crtc,
> u32 viewport_w, viewport_h;
> int r;
> bool bypass_lut = false;
> + const char *format_name;
>
> /* no fb bound */
> if (!atomic && !crtc->primary->fb) {
> @@ -1558,8 +1561,9 @@ static int avivo_crtc_do_set_base(struct drm_crtc *crtc,
> bypass_lut = true;
> break;
> default:
> - DRM_ERROR("Unsupported screen format %s\n",
> - drm_get_format_name(target_fb->pixel_format));
> + format_name = drm_get_format_name(target_fb->pixel_format);
> + DRM_ERROR("Unsupported screen format %s\n", format_name);
> + kfree(format_name);
> return -EINVAL;
> }
--
Jani Nikula, Intel Open Source Technology Center