drm/gem: Acquire reservation lock in drm_gem_{pin/unpin}()

Acquire the buffer object's reservation lock in drm_gem_pin() and
remove locking the drivers' GEM callbacks where necessary. Same for
unpin().

DRM drivers and memory managers modified by this patch will now have
correct dma-buf locking semantics: the caller is responsible for
holding the reservation lock when calling the pin or unpin callback.

DRM drivers and memory managers that are not modified will now be
protected against concurent invocation of their pin and unpin callbacks.

PRIME does not implement struct dma_buf_ops.pin, which requires
the caller to hold the reservation lock. It does implement struct
dma_buf_ops.attach, which requires to callee to acquire the
reservation lock. The PRIME code uses drm_gem_pin(), so locks
are now taken as specified. Same for unpin and detach.

The patch harmonizes GEM pin and unpin to have non-interruptible
reservation locking across all drivers, as is already the case for
vmap and vunmap. This affects gem-shmem, gem-vram, loongson, qxl and
radeon.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Zack Rusin <zack.rusin@broadcom.com>
Reviewed-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com> # virtio-gpu
Link: https://patchwork.freedesktop.org/patch/msgid/20240227113853.8464-10-tzimmermann@suse.de

diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
index 44a948b80ee14eb4d9f430b61bd0b7dab0afef17..e0f80c6a7096fb021283f92c610ce25e5e1c750b 100644 (file)
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -1161,7 +1161,7 @@ void drm_gem_print_info(struct drm_printer *p, unsigned int indent,
                obj->funcs->print_info(p, indent, obj);
 }
 
-int drm_gem_pin(struct drm_gem_object *obj)
+int drm_gem_pin_locked(struct drm_gem_object *obj)
 {
        if (obj->funcs->pin)
                return obj->funcs->pin(obj);
@@ -1169,12 +1169,30 @@ int drm_gem_pin(struct drm_gem_object *obj)
        return 0;
 }
 
-void drm_gem_unpin(struct drm_gem_object *obj)
+void drm_gem_unpin_locked(struct drm_gem_object *obj)
 {
        if (obj->funcs->unpin)
                obj->funcs->unpin(obj);
 }
 
+int drm_gem_pin(struct drm_gem_object *obj)
+{
+       int ret;
+
+       dma_resv_lock(obj->resv, NULL);
+       ret = drm_gem_pin_locked(obj);
+       dma_resv_unlock(obj->resv);
+
+       return ret;
+}
+
+void drm_gem_unpin(struct drm_gem_object *obj)
+{
+       dma_resv_lock(obj->resv, NULL);
+       drm_gem_unpin_locked(obj);
+       dma_resv_unlock(obj->resv);
+}
+
 int drm_gem_vmap(struct drm_gem_object *obj, struct iosys_map *map)
 {
        int ret;

diff --git a/drivers/gpu/drm/drm_gem_vram_helper.c b/drivers/gpu/drm/drm_gem_vram_helper.c
index 15029d89badf867dba79ed9a173de4ef46c21579..5a16b3e0a41348058368513dd74cae5db3b5bd18 100644 (file)
--- a/drivers/gpu/drm/drm_gem_vram_helper.c
+++ b/drivers/gpu/drm/drm_gem_vram_helper.c
@@ -774,11 +774,6 @@ EXPORT_SYMBOL(drm_gem_vram_simple_display_pipe_cleanup_fb);
 static int drm_gem_vram_object_pin(struct drm_gem_object *gem)
 {
        struct drm_gem_vram_object *gbo = drm_gem_vram_of_gem(gem);
-       int ret;
-
-       ret = ttm_bo_reserve(&gbo->bo, true, false, NULL);
-       if (ret)
-               return ret;
 
        /*
         * Fbdev console emulation is the use case of these PRIME
@@ -789,10 +784,7 @@ static int drm_gem_vram_object_pin(struct drm_gem_object *gem)
         * the buffer to be pinned to VRAM, implement a callback that
         * sets the flags accordingly.
         */
-       ret = drm_gem_vram_pin_locked(gbo, 0);
-       ttm_bo_unreserve(&gbo->bo);
-
-       return ret;
+       return drm_gem_vram_pin_locked(gbo, 0);
 }
 
 /**
@@ -803,13 +795,8 @@ static int drm_gem_vram_object_pin(struct drm_gem_object *gem)
 static void drm_gem_vram_object_unpin(struct drm_gem_object *gem)
 {
        struct drm_gem_vram_object *gbo = drm_gem_vram_of_gem(gem);
-       int ret;
 
-       ret = ttm_bo_reserve(&gbo->bo, true, false, NULL);
-       if (ret)
-               return;
        drm_gem_vram_unpin_locked(gbo);
-       ttm_bo_unreserve(&gbo->bo);
 }
 
 /**

diff --git a/drivers/gpu/drm/drm_internal.h b/drivers/gpu/drm/drm_internal.h
index d69744c9ac157761fcb3845bb7fa92db5c41db59..2215baef9a3e5a1397b1ab6eb7dc869c231e6121 100644 (file)
--- a/drivers/gpu/drm/drm_internal.h
+++ b/drivers/gpu/drm/drm_internal.h
@@ -173,6 +173,8 @@ void drm_gem_release(struct drm_device *dev, struct drm_file *file_private);
 void drm_gem_print_info(struct drm_printer *p, unsigned int indent,
                        const struct drm_gem_object *obj);
 
+int drm_gem_pin_locked(struct drm_gem_object *obj);
+void drm_gem_unpin_locked(struct drm_gem_object *obj);
 int drm_gem_pin(struct drm_gem_object *obj);
 void drm_gem_unpin(struct drm_gem_object *obj);
 int drm_gem_vmap(struct drm_gem_object *obj, struct iosys_map *map);

diff --git a/drivers/gpu/drm/loongson/lsdc_gem.c b/drivers/gpu/drm/loongson/lsdc_gem.c
index 04293df2f0de01223af7e92a09f9c8058839a6af..a720d8f53209338c14a9ac476e7d23e654a1b956 100644 (file)
--- a/drivers/gpu/drm/loongson/lsdc_gem.c
+++ b/drivers/gpu/drm/loongson/lsdc_gem.c
@@ -19,33 +19,24 @@ static int lsdc_gem_prime_pin(struct drm_gem_object *obj)
        struct lsdc_bo *lbo = gem_to_lsdc_bo(obj);
        int ret;
 
-       ret = lsdc_bo_reserve(lbo);
-       if (unlikely(ret))
-               return ret;
+       dma_resv_assert_held(obj->resv);
 
        ret = lsdc_bo_pin(lbo, LSDC_GEM_DOMAIN_GTT, NULL);
        if (likely(ret == 0))
                lbo->sharing_count++;
 
-       lsdc_bo_unreserve(lbo);
-
        return ret;
 }
 
 static void lsdc_gem_prime_unpin(struct drm_gem_object *obj)
 {
        struct lsdc_bo *lbo = gem_to_lsdc_bo(obj);
-       int ret;
 
-       ret = lsdc_bo_reserve(lbo);
-       if (unlikely(ret))
-               return;
+       dma_resv_assert_held(obj->resv);
 
        lsdc_bo_unpin(lbo);
        if (lbo->sharing_count)
                lbo->sharing_count--;
-
-       lsdc_bo_unreserve(lbo);
 }
 
 static struct sg_table *lsdc_gem_prime_get_sg_table(struct drm_gem_object *obj)

diff --git a/drivers/gpu/drm/msm/msm_gem_prime.c b/drivers/gpu/drm/msm/msm_gem_prime.c
index 0d22df53ab98a032aa997f042d4ea1ea9e3d1dd2..ee267490c93597a29c09676c9235832ecd845cfd 100644 (file)
--- a/drivers/gpu/drm/msm/msm_gem_prime.c
+++ b/drivers/gpu/drm/msm/msm_gem_prime.c
@@ -53,11 +53,9 @@ int msm_gem_prime_pin(struct drm_gem_object *obj)
        if (obj->import_attach)
                return 0;
 
-       msm_gem_lock(obj);
        pages = msm_gem_pin_pages_locked(obj);
        if (IS_ERR(pages))
                ret = PTR_ERR(pages);
-       msm_gem_unlock(obj);
 
        return ret;
 }
@@ -67,7 +65,5 @@ void msm_gem_prime_unpin(struct drm_gem_object *obj)
        if (obj->import_attach)
                return;
 
-       msm_gem_lock(obj);
        msm_gem_unpin_pages_locked(obj);
-       msm_gem_unlock(obj);
 }

diff --git a/drivers/gpu/drm/nouveau/nouveau_prime.c b/drivers/gpu/drm/nouveau/nouveau_prime.c
index 774f9bd03110276b08a8b7b0e29e2edc8f2b7b99..b58ab595faf8278c661ce2c9988c09c98f47a515 100644 (file)
--- a/drivers/gpu/drm/nouveau/nouveau_prime.c
+++ b/drivers/gpu/drm/nouveau/nouveau_prime.c
@@ -86,17 +86,12 @@ unlock:
 int nouveau_gem_prime_pin(struct drm_gem_object *obj)
 {
        struct nouveau_bo *nvbo = nouveau_gem_object(obj);
-       struct ttm_buffer_object *bo = &nvbo->bo;
        int ret;
 
-       ret = ttm_bo_reserve(bo, false, false, NULL);
-       if (ret)
-               return -EINVAL;
        /* pin buffer into GTT */
        ret = nouveau_bo_pin_locked(nvbo, NOUVEAU_GEM_DOMAIN_GART, false);
        if (ret)
                ret = -EINVAL;
-       ttm_bo_unreserve(bo);
 
        return ret;
 }
@@ -104,14 +99,8 @@ int nouveau_gem_prime_pin(struct drm_gem_object *obj)
 void nouveau_gem_prime_unpin(struct drm_gem_object *obj)
 {
        struct nouveau_bo *nvbo = nouveau_gem_object(obj);
-       struct ttm_buffer_object *bo = &nvbo->bo;
-       int ret;
 
-       ret = ttm_bo_reserve(bo, false, false, NULL);
-       if (ret)
-               return;
        nouveau_bo_unpin_locked(nvbo);
-       ttm_bo_unreserve(bo);
 }
 
 struct dma_buf *nouveau_gem_prime_export(struct drm_gem_object *gobj,

diff --git a/drivers/gpu/drm/qxl/qxl_prime.c b/drivers/gpu/drm/qxl/qxl_prime.c
index f2646603e12eb40284741890e19a6816a82208dc..19bf551a7b311077aaf4b6bf786fe9e10b4054f5 100644 (file)
--- a/drivers/gpu/drm/qxl/qxl_prime.c
+++ b/drivers/gpu/drm/qxl/qxl_prime.c
@@ -31,27 +31,15 @@
 int qxl_gem_prime_pin(struct drm_gem_object *obj)
 {
        struct qxl_bo *bo = gem_to_qxl_bo(obj);
-       int r;
 
-       r = qxl_bo_reserve(bo);
-       if (r)
-               return r;
-       r = qxl_bo_pin_locked(bo);
-       qxl_bo_unreserve(bo);
-
-       return r;
+       return qxl_bo_pin_locked(bo);
 }
 
 void qxl_gem_prime_unpin(struct drm_gem_object *obj)
 {
        struct qxl_bo *bo = gem_to_qxl_bo(obj);
-       int r;
 
-       r = qxl_bo_reserve(bo);
-       if (r)
-               return;
        qxl_bo_unpin_locked(bo);
-       qxl_bo_unreserve(bo);
 }
 
 struct sg_table *qxl_gem_prime_get_sg_table(struct drm_gem_object *obj)

diff --git a/drivers/gpu/drm/radeon/radeon_prime.c b/drivers/gpu/drm/radeon/radeon_prime.c
index b3cfc99f4d7ede0493a2cc893be5ff568892cce2..a77881f035e7a1b0a996fed8ee357e3ff2a4978a 100644 (file)
--- a/drivers/gpu/drm/radeon/radeon_prime.c
+++ b/drivers/gpu/drm/radeon/radeon_prime.c
@@ -73,32 +73,21 @@ int radeon_gem_prime_pin(struct drm_gem_object *obj)
        struct radeon_bo *bo = gem_to_radeon_bo(obj);
        int ret = 0;
 
-       ret = radeon_bo_reserve(bo, false);
-       if (unlikely(ret != 0))
-               return ret;
-
        /* pin buffer into GTT */
        ret = radeon_bo_pin(bo, RADEON_GEM_DOMAIN_GTT, NULL);
        if (likely(ret == 0))
                bo->prime_shared_count++;
 
-       radeon_bo_unreserve(bo);
        return ret;
 }
 
 void radeon_gem_prime_unpin(struct drm_gem_object *obj)
 {
        struct radeon_bo *bo = gem_to_radeon_bo(obj);
-       int ret = 0;
-
-       ret = radeon_bo_reserve(bo, false);
-       if (unlikely(ret != 0))
-               return;
 
        radeon_bo_unpin(bo);
        if (bo->prime_shared_count)
                bo->prime_shared_count--;
-       radeon_bo_unreserve(bo);
 }
 
 

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_gem.c b/drivers/gpu/drm/vmwgfx/vmwgfx_gem.c
index 12787bb9c111d10db997b9db650c6bb1069c26ef..186150f41fbcc8dc400d4a584a0d0f5bf64eeac6 100644 (file)
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_gem.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_gem.c
@@ -48,33 +48,20 @@ static void vmw_gem_object_close(struct drm_gem_object *obj,
 {
 }
 
-static int vmw_gem_pin_private(struct drm_gem_object *obj, bool do_pin)
+static int vmw_gem_object_pin(struct drm_gem_object *obj)
 {
-       struct ttm_buffer_object *bo = drm_gem_ttm_of_gem(obj);
        struct vmw_bo *vbo = to_vmw_bo(obj);
-       int ret;
-
-       ret = ttm_bo_reserve(bo, false, false, NULL);
-       if (unlikely(ret != 0))
-               goto err;
-
-       vmw_bo_pin_reserved(vbo, do_pin);
-
-       ttm_bo_unreserve(bo);
-
-err:
-       return ret;
-}
 
+       vmw_bo_pin_reserved(vbo, true);
 
-static int vmw_gem_object_pin(struct drm_gem_object *obj)
-{
-       return vmw_gem_pin_private(obj, true);
+       return 0;
 }
 
 static void vmw_gem_object_unpin(struct drm_gem_object *obj)
 {
-       vmw_gem_pin_private(obj, false);
+       struct vmw_bo *vbo = to_vmw_bo(obj);
+
+       vmw_bo_pin_reserved(vbo, false);
 }
 
 static struct sg_table *vmw_gem_object_get_sg_table(struct drm_gem_object *obj)

diff --git a/include/drm/drm_gem_shmem_helper.h b/include/drm/drm_gem_shmem_helper.h
index eb12aa9a8c5569c880e168a191f89f76931172e4..efbc9f27312b53fda76500556cd9cdd1ffadd660 100644 (file)
--- a/include/drm/drm_gem_shmem_helper.h
+++ b/include/drm/drm_gem_shmem_helper.h
@@ -175,15 +175,8 @@ static inline void drm_gem_shmem_object_print_info(struct drm_printer *p, unsign
 static inline int drm_gem_shmem_object_pin(struct drm_gem_object *obj)
 {
        struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
-       int ret;
 
-       ret = dma_resv_lock_interruptible(shmem->base.resv, NULL);
-       if (ret)
-               return ret;
-       ret = drm_gem_shmem_pin_locked(shmem);
-       dma_resv_unlock(shmem->base.resv);
-
-       return ret;
+       return drm_gem_shmem_pin_locked(shmem);
 }
 
 /**
@@ -197,9 +190,7 @@ static inline void drm_gem_shmem_object_unpin(struct drm_gem_object *obj)
 {
        struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
 
-       dma_resv_lock(shmem->base.resv, NULL);
        drm_gem_shmem_unpin_locked(shmem);
-       dma_resv_unlock(shmem->base.resv);
 }
 
 /**