From: Daniel Vetter Date: Sun, 25 Mar 2012 17:47:28 +0000 (+0200) Subject: drm/i915: merge shmem_pwrite slow&fast-path X-Git-Tag: firefly_0821_release~3680^2~2315^2~115^2~69 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=e244a443bf72bccb44c75cadf04720101d1f313a;p=firefly-linux-kernel-4.4.55.git drm/i915: merge shmem_pwrite 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 --- diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index 09c033e5e02b..a2547528a9d4 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -691,84 +691,11 @@ out_unpin_pages: return ret; } -/** - * This is the fast shmem pwrite path, which attempts to directly - * copy_from_user into the kmapped pages backing the object. - */ -static int -i915_gem_shmem_pwrite_fast(struct drm_device *dev, - struct drm_i915_gem_object *obj, - struct drm_i915_gem_pwrite *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; - obj->dirty = 1; - - 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_from_user_inatomic(vaddr + page_offset, - user_data, - page_length); - kunmap_atomic(vaddr); - - set_page_dirty(page); - mark_page_accessed(page); - page_cache_release(page); - - /* If we get a fault while copying data, then (presumably) our - * source page isn't available. Return the error and we'll - * retry in the slow path. - */ - if (ret) - return -EFAULT; - - remain -= page_length; - user_data += page_length; - offset += page_length; - } - - return 0; -} - -/** - * This is the fallback shmem pwrite path, which uses get_user_pages to pin - * the memory and maps it using kmap_atomic for copying. - * - * This avoids taking mmap_sem for faulting on the user's address while the - * struct_mutex is held. - */ static int -i915_gem_shmem_pwrite_slow(struct drm_device *dev, - struct drm_i915_gem_object *obj, - struct drm_i915_gem_pwrite *args, - struct drm_file *file) +i915_gem_shmem_pwrite(struct drm_device *dev, + struct drm_i915_gem_object *obj, + struct drm_i915_gem_pwrite *args, + struct drm_file *file) { struct address_space *mapping = obj->base.filp->f_path.dentry->d_inode->i_mapping; ssize_t remain; @@ -776,6 +703,7 @@ i915_gem_shmem_pwrite_slow(struct drm_device *dev, char __user *user_data; 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; @@ -785,8 +713,6 @@ i915_gem_shmem_pwrite_slow(struct drm_device *dev, offset = args->offset; obj->dirty = 1; - mutex_unlock(&dev->struct_mutex); - while (remain > 0) { struct page *page; char *vaddr; @@ -811,6 +737,21 @@ i915_gem_shmem_pwrite_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_from_user_inatomic(vaddr + shmem_page_offset, + user_data, + 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_from_user_swizzled(vaddr, shmem_page_offset, @@ -822,6 +763,8 @@ i915_gem_shmem_pwrite_slow(struct drm_device *dev, page_length); kunmap(page); + mutex_lock(&dev->struct_mutex); +next_page: set_page_dirty(page); mark_page_accessed(page); page_cache_release(page); @@ -837,15 +780,16 @@ i915_gem_shmem_pwrite_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); - /* and flush dirty cachelines in case the object isn't in the cpu write - * domain anymore. */ - if (obj->base.write_domain != I915_GEM_DOMAIN_CPU) { - i915_gem_clflush_object(obj); - intel_gtt_chipset_flush(); + if (hit_slowpath) { + /* Fixup: Kill any reinstated backing storage pages */ + if (obj->madv == __I915_MADV_PURGED) + i915_gem_object_truncate(obj); + /* and flush dirty cachelines in case the object isn't in the cpu write + * domain anymore. */ + if (obj->base.write_domain != I915_GEM_DOMAIN_CPU) { + i915_gem_clflush_object(obj); + intel_gtt_chipset_flush(); + } } return ret; @@ -939,11 +883,7 @@ out_unpin: if (ret) goto out; - ret = -EFAULT; - if (!i915_gem_object_needs_bit17_swizzle(obj)) - ret = i915_gem_shmem_pwrite_fast(dev, obj, args, file); - if (ret == -EFAULT) - ret = i915_gem_shmem_pwrite_slow(dev, obj, args, file); + ret = i915_gem_shmem_pwrite(dev, obj, args, file); out: drm_gem_object_unreference(&obj->base);