From dbf7bff074d5fdc87c61b1b41d8e809109cf0bf8 Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Sun, 25 Mar 2012 19:47:29 +0200 Subject: [PATCH] drm/i915: merge shmem_pread slow&fast-path With the previous rewrite, they've become essential identical. v2: Simplify the page_do_bit17_swizzling logic as suggested by Chris Wilson. Tested-by: Chris Wilson Reviewed-by: Chris Wilson Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/i915_gem.c | 108 ++++++++------------------------ 1 file changed, 27 insertions(+), 81 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index a2547528a9d4..1855e72859a8 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -239,66 +239,6 @@ static int i915_gem_object_needs_bit17_swizzle(struct drm_i915_gem_object *obj) obj->tiling_mode != I915_TILING_NONE; } -/** - * This is the fast shmem pread path, which attempts to copy_from_user directly - * from the backing pages of the object to the user's address space. On a - * fault, it fails so we can fall back to i915_gem_shmem_pwrite_slow(). - */ -static int -i915_gem_shmem_pread_fast(struct drm_device *dev, - struct drm_i915_gem_object *obj, - struct drm_i915_gem_pread *args, - struct drm_file *file) -{ - struct address_space *mapping = obj->base.filp->f_path.dentry->d_inode->i_mapping; - ssize_t remain; - loff_t offset; - char __user *user_data; - int page_offset, page_length; - - user_data = (char __user *) (uintptr_t) args->data_ptr; - remain = args->size; - - offset = args->offset; - - while (remain > 0) { - struct page *page; - char *vaddr; - int ret; - - /* Operation in this page - * - * page_offset = offset within page - * page_length = bytes to copy for this page - */ - page_offset = offset_in_page(offset); - page_length = remain; - if ((page_offset + remain) > PAGE_SIZE) - page_length = PAGE_SIZE - page_offset; - - page = shmem_read_mapping_page(mapping, offset >> PAGE_SHIFT); - if (IS_ERR(page)) - return PTR_ERR(page); - - vaddr = kmap_atomic(page); - ret = __copy_to_user_inatomic(user_data, - vaddr + page_offset, - page_length); - kunmap_atomic(vaddr); - - mark_page_accessed(page); - page_cache_release(page); - if (ret) - return -EFAULT; - - remain -= page_length; - user_data += page_length; - offset += page_length; - } - - return 0; -} - static inline int __copy_to_user_swizzled(char __user *cpu_vaddr, const char *gpu_vaddr, int gpu_offset, @@ -351,17 +291,11 @@ __copy_from_user_swizzled(char __user *gpu_vaddr, int gpu_offset, return 0; } -/** - * This is the fallback shmem pread path, which allocates temporary storage - * in kernel space to copy_to_user into outside of the struct_mutex, so we - * can copy out of the object's backing pages while holding the struct mutex - * and not take page faults. - */ static int -i915_gem_shmem_pread_slow(struct drm_device *dev, - struct drm_i915_gem_object *obj, - struct drm_i915_gem_pread *args, - struct drm_file *file) +i915_gem_shmem_pread(struct drm_device *dev, + struct drm_i915_gem_object *obj, + struct drm_i915_gem_pread *args, + struct drm_file *file) { struct address_space *mapping = obj->base.filp->f_path.dentry->d_inode->i_mapping; char __user *user_data; @@ -369,6 +303,7 @@ i915_gem_shmem_pread_slow(struct drm_device *dev, loff_t offset; int shmem_page_offset, page_length, ret = 0; int obj_do_bit17_swizzling, page_do_bit17_swizzling; + int hit_slowpath = 0; user_data = (char __user *) (uintptr_t) args->data_ptr; remain = args->size; @@ -377,8 +312,6 @@ i915_gem_shmem_pread_slow(struct drm_device *dev, offset = args->offset; - mutex_unlock(&dev->struct_mutex); - while (remain > 0) { struct page *page; char *vaddr; @@ -402,6 +335,20 @@ i915_gem_shmem_pread_slow(struct drm_device *dev, page_do_bit17_swizzling = obj_do_bit17_swizzling && (page_to_phys(page) & (1 << 17)) != 0; + if (!page_do_bit17_swizzling) { + vaddr = kmap_atomic(page); + ret = __copy_to_user_inatomic(user_data, + vaddr + shmem_page_offset, + page_length); + kunmap_atomic(vaddr); + if (ret == 0) + goto next_page; + } + + hit_slowpath = 1; + + mutex_unlock(&dev->struct_mutex); + vaddr = kmap(page); if (page_do_bit17_swizzling) ret = __copy_to_user_swizzled(user_data, @@ -413,6 +360,8 @@ i915_gem_shmem_pread_slow(struct drm_device *dev, page_length); kunmap(page); + mutex_lock(&dev->struct_mutex); +next_page: mark_page_accessed(page); page_cache_release(page); @@ -427,10 +376,11 @@ i915_gem_shmem_pread_slow(struct drm_device *dev, } out: - mutex_lock(&dev->struct_mutex); - /* Fixup: Kill any reinstated backing storage pages */ - if (obj->madv == __I915_MADV_PURGED) - i915_gem_object_truncate(obj); + if (hit_slowpath) { + /* Fixup: Kill any reinstated backing storage pages */ + if (obj->madv == __I915_MADV_PURGED) + i915_gem_object_truncate(obj); + } return ret; } @@ -486,11 +436,7 @@ i915_gem_pread_ioctl(struct drm_device *dev, void *data, if (ret) goto out; - ret = -EFAULT; - if (!i915_gem_object_needs_bit17_swizzle(obj)) - ret = i915_gem_shmem_pread_fast(dev, obj, args, file); - if (ret == -EFAULT) - ret = i915_gem_shmem_pread_slow(dev, obj, args, file); + ret = i915_gem_shmem_pread(dev, obj, args, file); out: drm_gem_object_unreference(&obj->base); -- 2.39.5