On Thu, 21 Oct 2021 at 18:30, Matthew Auld matthew.william.auld@gmail.com wrote:
On Thu, 21 Oct 2021 at 11:36, Maarten Lankhorst maarten.lankhorst@linux.intel.com wrote:
Big delta, but boils down to moving set_pages to i915_vma.c, and removing the special handling, all callers use the defaults anyway. We only remap in ggtt, so default case will fall through.
Because we still don't require locking in i915_vma_unpin(), handle this by using xchg in get_pages(), as it's locked with obj->mutex, and cmpxchg in unpin, which only fails if we race a against a new pin.
Signed-off-by: Maarten Lankhorst maarten.lankhorst@linux.intel.com
drivers/gpu/drm/i915/display/intel_dpt.c | 2 - drivers/gpu/drm/i915/gt/gen6_ppgtt.c | 15 - drivers/gpu/drm/i915/gt/intel_ggtt.c | 345 ---------------- drivers/gpu/drm/i915/gt/intel_gtt.c | 13 - drivers/gpu/drm/i915/gt/intel_gtt.h | 7 - drivers/gpu/drm/i915/gt/intel_ppgtt.c | 12 - drivers/gpu/drm/i915/i915_vma.c | 388 ++++++++++++++++-- drivers/gpu/drm/i915/i915_vma.h | 3 + drivers/gpu/drm/i915/i915_vma_types.h | 1 - drivers/gpu/drm/i915/selftests/i915_gem_gtt.c | 12 +- drivers/gpu/drm/i915/selftests/mock_gtt.c | 4 - 11 files changed, 368 insertions(+), 434 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_dpt.c b/drivers/gpu/drm/i915/display/intel_dpt.c index 8f7b1f7534a4..ef428f3fc538 100644 --- a/drivers/gpu/drm/i915/display/intel_dpt.c +++ b/drivers/gpu/drm/i915/display/intel_dpt.c @@ -221,8 +221,6 @@ intel_dpt_create(struct intel_framebuffer *fb)
vm->vma_ops.bind_vma = dpt_bind_vma; vm->vma_ops.unbind_vma = dpt_unbind_vma;
vm->vma_ops.set_pages = ggtt_set_pages;vm->vma_ops.clear_pages = clear_pages; vm->pte_encode = gen8_ggtt_pte_encode;diff --git a/drivers/gpu/drm/i915/gt/gen6_ppgtt.c b/drivers/gpu/drm/i915/gt/gen6_ppgtt.c index 5caa1703716e..5c048b4ccd4d 100644 --- a/drivers/gpu/drm/i915/gt/gen6_ppgtt.c +++ b/drivers/gpu/drm/i915/gt/gen6_ppgtt.c @@ -270,19 +270,6 @@ static void gen6_ppgtt_cleanup(struct i915_address_space *vm) free_pd(&ppgtt->base.vm, ppgtt->base.pd); }
-static int pd_vma_set_pages(struct i915_vma *vma) -{
vma->pages = ERR_PTR(-ENODEV);return 0;-}
-static void pd_vma_clear_pages(struct i915_vma *vma) -{
GEM_BUG_ON(!vma->pages);vma->pages = NULL;-}
static void pd_vma_bind(struct i915_address_space *vm, struct i915_vm_pt_stash *stash, struct i915_vma *vma, @@ -322,8 +309,6 @@ static void pd_vma_unbind(struct i915_address_space *vm, struct i915_vma *vma) }
static const struct i915_vma_ops pd_vma_ops = {
.set_pages = pd_vma_set_pages,.clear_pages = pd_vma_clear_pages, .bind_vma = pd_vma_bind, .unbind_vma = pd_vma_unbind,}; diff --git a/drivers/gpu/drm/i915/gt/intel_ggtt.c b/drivers/gpu/drm/i915/gt/intel_ggtt.c index f17383e76eb7..6da57199bb33 100644 --- a/drivers/gpu/drm/i915/gt/intel_ggtt.c +++ b/drivers/gpu/drm/i915/gt/intel_ggtt.c @@ -20,9 +20,6 @@ #include "intel_gtt.h" #include "gen8_ppgtt.h"
-static int -i915_get_ggtt_vma_pages(struct i915_vma *vma);
static void i915_ggtt_color_adjust(const struct drm_mm_node *node, unsigned long color, u64 *start, @@ -875,21 +872,6 @@ static int ggtt_probe_common(struct i915_ggtt *ggtt, u64 size) return 0; }
-int ggtt_set_pages(struct i915_vma *vma) -{
int ret;GEM_BUG_ON(vma->pages);ret = i915_get_ggtt_vma_pages(vma);if (ret)return ret;vma->page_sizes = vma->obj->mm.page_sizes;return 0;-}
static void gen6_gmch_remove(struct i915_address_space *vm) { struct i915_ggtt *ggtt = i915_vm_to_ggtt(vm); @@ -950,8 +932,6 @@ static int gen8_gmch_probe(struct i915_ggtt *ggtt)
ggtt->vm.vma_ops.bind_vma = ggtt_bind_vma; ggtt->vm.vma_ops.unbind_vma = ggtt_unbind_vma;
ggtt->vm.vma_ops.set_pages = ggtt_set_pages;ggtt->vm.vma_ops.clear_pages = clear_pages; ggtt->vm.pte_encode = gen8_ggtt_pte_encode;@@ -1100,8 +1080,6 @@ static int gen6_gmch_probe(struct i915_ggtt *ggtt)
ggtt->vm.vma_ops.bind_vma = ggtt_bind_vma; ggtt->vm.vma_ops.unbind_vma = ggtt_unbind_vma;
ggtt->vm.vma_ops.set_pages = ggtt_set_pages;ggtt->vm.vma_ops.clear_pages = clear_pages; return ggtt_probe_common(ggtt, size);} @@ -1145,8 +1123,6 @@ static int i915_gmch_probe(struct i915_ggtt *ggtt)
ggtt->vm.vma_ops.bind_vma = ggtt_bind_vma; ggtt->vm.vma_ops.unbind_vma = ggtt_unbind_vma;
ggtt->vm.vma_ops.set_pages = ggtt_set_pages;ggtt->vm.vma_ops.clear_pages = clear_pages; if (unlikely(ggtt->do_idle_maps)) drm_notice(&i915->drm,@@ -1294,324 +1270,3 @@ void i915_ggtt_resume(struct i915_ggtt *ggtt)
intel_ggtt_restore_fences(ggtt);}
-static struct scatterlist * -rotate_pages(struct drm_i915_gem_object *obj, unsigned int offset,
unsigned int width, unsigned int height,unsigned int src_stride, unsigned int dst_stride,struct sg_table *st, struct scatterlist *sg)-{
unsigned int column, row;unsigned int src_idx;for (column = 0; column < width; column++) {unsigned int left;src_idx = src_stride * (height - 1) + column + offset;for (row = 0; row < height; row++) {st->nents++;/** We don't need the pages, but need to initialize* the entries so the sg list can be happily traversed.* The only thing we need are DMA addresses.*/sg_set_page(sg, NULL, I915_GTT_PAGE_SIZE, 0);sg_dma_address(sg) =i915_gem_object_get_dma_address(obj, src_idx);sg_dma_len(sg) = I915_GTT_PAGE_SIZE;sg = sg_next(sg);src_idx -= src_stride;}left = (dst_stride - height) * I915_GTT_PAGE_SIZE;if (!left)continue;st->nents++;/** The DE ignores the PTEs for the padding tiles, the sg entry* here is just a conenience to indicate how many padding PTEs* to insert at this spot.*/sg_set_page(sg, NULL, left, 0);sg_dma_address(sg) = 0;sg_dma_len(sg) = left;sg = sg_next(sg);}return sg;-}
-static noinline struct sg_table * -intel_rotate_pages(struct intel_rotation_info *rot_info,
struct drm_i915_gem_object *obj)-{
unsigned int size = intel_rotation_info_size(rot_info);struct drm_i915_private *i915 = to_i915(obj->base.dev);struct sg_table *st;struct scatterlist *sg;int ret = -ENOMEM;int i;/* Allocate target SG list. */st = kmalloc(sizeof(*st), GFP_KERNEL);if (!st)goto err_st_alloc;ret = sg_alloc_table(st, size, GFP_KERNEL);if (ret)goto err_sg_alloc;st->nents = 0;sg = st->sgl;for (i = 0 ; i < ARRAY_SIZE(rot_info->plane); i++)sg = rotate_pages(obj, rot_info->plane[i].offset,rot_info->plane[i].width, rot_info->plane[i].height,rot_info->plane[i].src_stride,rot_info->plane[i].dst_stride,st, sg);return st;-err_sg_alloc:
kfree(st);-err_st_alloc:
drm_dbg(&i915->drm, "Failed to create rotated mapping for object size %zu! (%ux%u tiles, %u pages)\n",obj->base.size, rot_info->plane[0].width,rot_info->plane[0].height, size);return ERR_PTR(ret);-}
-static struct scatterlist * -remap_pages(struct drm_i915_gem_object *obj,
unsigned int offset, unsigned int alignment_pad,unsigned int width, unsigned int height,unsigned int src_stride, unsigned int dst_stride,struct sg_table *st, struct scatterlist *sg)-{
unsigned int row;if (alignment_pad) {st->nents++;/** The DE ignores the PTEs for the padding tiles, the sg entry* here is just a convenience to indicate how many padding PTEs* to insert at this spot.*/sg_set_page(sg, NULL, alignment_pad * 4096, 0);sg_dma_address(sg) = 0;sg_dma_len(sg) = alignment_pad * 4096;sg = sg_next(sg);}for (row = 0; row < height; row++) {unsigned int left = width * I915_GTT_PAGE_SIZE;while (left) {dma_addr_t addr;unsigned int length;/** We don't need the pages, but need to initialize* the entries so the sg list can be happily traversed.* The only thing we need are DMA addresses.*/addr = i915_gem_object_get_dma_address_len(obj, offset, &length);length = min(left, length);st->nents++;sg_set_page(sg, NULL, length, 0);sg_dma_address(sg) = addr;sg_dma_len(sg) = length;sg = sg_next(sg);offset += length / I915_GTT_PAGE_SIZE;left -= length;}offset += src_stride - width;left = (dst_stride - width) * I915_GTT_PAGE_SIZE;if (!left)continue;st->nents++;/** The DE ignores the PTEs for the padding tiles, the sg entry* here is just a conenience to indicate how many padding PTEs* to insert at this spot.*/sg_set_page(sg, NULL, left, 0);sg_dma_address(sg) = 0;sg_dma_len(sg) = left;sg = sg_next(sg);}return sg;-}
-static noinline struct sg_table * -intel_remap_pages(struct intel_remapped_info *rem_info,
struct drm_i915_gem_object *obj)-{
unsigned int size = intel_remapped_info_size(rem_info);struct drm_i915_private *i915 = to_i915(obj->base.dev);struct sg_table *st;struct scatterlist *sg;unsigned int gtt_offset = 0;int ret = -ENOMEM;int i;/* Allocate target SG list. */st = kmalloc(sizeof(*st), GFP_KERNEL);if (!st)goto err_st_alloc;ret = sg_alloc_table(st, size, GFP_KERNEL);if (ret)goto err_sg_alloc;st->nents = 0;sg = st->sgl;for (i = 0 ; i < ARRAY_SIZE(rem_info->plane); i++) {unsigned int alignment_pad = 0;if (rem_info->plane_alignment)alignment_pad = ALIGN(gtt_offset, rem_info->plane_alignment) - gtt_offset;sg = remap_pages(obj,rem_info->plane[i].offset, alignment_pad,rem_info->plane[i].width, rem_info->plane[i].height,rem_info->plane[i].src_stride, rem_info->plane[i].dst_stride,st, sg);gtt_offset += alignment_pad +rem_info->plane[i].dst_stride * rem_info->plane[i].height;}i915_sg_trim(st);return st;-err_sg_alloc:
kfree(st);-err_st_alloc:
drm_dbg(&i915->drm, "Failed to create remapped mapping for object size %zu! (%ux%u tiles, %u pages)\n",obj->base.size, rem_info->plane[0].width,rem_info->plane[0].height, size);return ERR_PTR(ret);-}
-static noinline struct sg_table * -intel_partial_pages(const struct i915_ggtt_view *view,
struct drm_i915_gem_object *obj)-{
struct sg_table *st;struct scatterlist *sg, *iter;unsigned int count = view->partial.size;unsigned int offset;int ret = -ENOMEM;st = kmalloc(sizeof(*st), GFP_KERNEL);if (!st)goto err_st_alloc;ret = sg_alloc_table(st, count, GFP_KERNEL);if (ret)goto err_sg_alloc;iter = i915_gem_object_get_sg_dma(obj, view->partial.offset, &offset);GEM_BUG_ON(!iter);sg = st->sgl;st->nents = 0;do {unsigned int len;len = min(sg_dma_len(iter) - (offset << PAGE_SHIFT),count << PAGE_SHIFT);sg_set_page(sg, NULL, len, 0);sg_dma_address(sg) =sg_dma_address(iter) + (offset << PAGE_SHIFT);sg_dma_len(sg) = len;st->nents++;count -= len >> PAGE_SHIFT;if (count == 0) {sg_mark_end(sg);i915_sg_trim(st); /* Drop any unused tail entries. */return st;}sg = __sg_next(sg);iter = __sg_next(iter);offset = 0;} while (1);-err_sg_alloc:
kfree(st);-err_st_alloc:
return ERR_PTR(ret);-}
-static int -i915_get_ggtt_vma_pages(struct i915_vma *vma) -{
int ret;/** The vma->pages are only valid within the lifespan of the borrowed* obj->mm.pages. When the obj->mm.pages sg_table is regenerated, so* must be the vma->pages. A simple rule is that vma->pages must only* be accessed when the obj->mm.pages are pinned.*/GEM_BUG_ON(!i915_gem_object_has_pinned_pages(vma->obj));switch (vma->ggtt_view.type) {default:GEM_BUG_ON(vma->ggtt_view.type);fallthrough;case I915_GGTT_VIEW_NORMAL:vma->pages = vma->obj->mm.pages;return 0;case I915_GGTT_VIEW_ROTATED:vma->pages =intel_rotate_pages(&vma->ggtt_view.rotated, vma->obj);break;case I915_GGTT_VIEW_REMAPPED:vma->pages =intel_remap_pages(&vma->ggtt_view.remapped, vma->obj);break;case I915_GGTT_VIEW_PARTIAL:vma->pages = intel_partial_pages(&vma->ggtt_view, vma->obj);break;}ret = 0;if (IS_ERR(vma->pages)) {ret = PTR_ERR(vma->pages);vma->pages = NULL;drm_err(&vma->vm->i915->drm,"Failed to get pages for VMA view type %u (%d)!\n",vma->ggtt_view.type, ret);}return ret;-} diff --git a/drivers/gpu/drm/i915/gt/intel_gtt.c b/drivers/gpu/drm/i915/gt/intel_gtt.c index 67d14afa6623..12eed5fcb17a 100644 --- a/drivers/gpu/drm/i915/gt/intel_gtt.c +++ b/drivers/gpu/drm/i915/gt/intel_gtt.c @@ -221,19 +221,6 @@ void i915_address_space_init(struct i915_address_space *vm, int subclass) INIT_LIST_HEAD(&vm->bound_list); }
-void clear_pages(struct i915_vma *vma) -{
GEM_BUG_ON(!vma->pages);if (vma->pages != vma->obj->mm.pages) {sg_free_table(vma->pages);kfree(vma->pages);}vma->pages = NULL;memset(&vma->page_sizes, 0, sizeof(vma->page_sizes));-}
void *__px_vaddr(struct drm_i915_gem_object *p) { enum i915_map_type type; diff --git a/drivers/gpu/drm/i915/gt/intel_gtt.h b/drivers/gpu/drm/i915/gt/intel_gtt.h index bc6750263359..306e7645fdc5 100644 --- a/drivers/gpu/drm/i915/gt/intel_gtt.h +++ b/drivers/gpu/drm/i915/gt/intel_gtt.h @@ -206,9 +206,6 @@ struct i915_vma_ops { */ void (*unbind_vma)(struct i915_address_space *vm, struct i915_vma *vma);
int (*set_pages)(struct i915_vma *vma);void (*clear_pages)(struct i915_vma *vma);};
struct i915_address_space { @@ -594,10 +591,6 @@ release_pd_entry(struct i915_page_directory * const pd, const struct drm_i915_gem_object * const scratch); void gen6_ggtt_invalidate(struct i915_ggtt *ggtt);
-int ggtt_set_pages(struct i915_vma *vma); -int ppgtt_set_pages(struct i915_vma *vma); -void clear_pages(struct i915_vma *vma);
void ppgtt_bind_vma(struct i915_address_space *vm, struct i915_vm_pt_stash *stash, struct i915_vma *vma, diff --git a/drivers/gpu/drm/i915/gt/intel_ppgtt.c b/drivers/gpu/drm/i915/gt/intel_ppgtt.c index 4396bfd630d8..083b3090c69c 100644 --- a/drivers/gpu/drm/i915/gt/intel_ppgtt.c +++ b/drivers/gpu/drm/i915/gt/intel_ppgtt.c @@ -289,16 +289,6 @@ void i915_vm_free_pt_stash(struct i915_address_space *vm, } }
-int ppgtt_set_pages(struct i915_vma *vma) -{
GEM_BUG_ON(vma->pages);vma->pages = vma->obj->mm.pages;vma->page_sizes = vma->obj->mm.page_sizes;return 0;-}
void ppgtt_init(struct i915_ppgtt *ppgtt, struct intel_gt *gt, unsigned long lmem_pt_obj_flags) { @@ -315,6 +305,4 @@ void ppgtt_init(struct i915_ppgtt *ppgtt, struct intel_gt *gt,
ppgtt->vm.vma_ops.bind_vma = ppgtt_bind_vma; ppgtt->vm.vma_ops.unbind_vma = ppgtt_unbind_vma;
ppgtt->vm.vma_ops.set_pages = ppgtt_set_pages;ppgtt->vm.vma_ops.clear_pages = clear_pages;} diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c index ac09b685678a..bacc8d68e495 100644 --- a/drivers/gpu/drm/i915/i915_vma.c +++ b/drivers/gpu/drm/i915/i915_vma.c @@ -112,7 +112,6 @@ vma_create(struct drm_i915_gem_object *obj, return ERR_PTR(-ENOMEM);
kref_init(&vma->ref);
mutex_init(&vma->pages_mutex); vma->vm = i915_vm_get(vm); vma->ops = &vm->vma_ops; vma->obj = obj;@@ -789,10 +788,343 @@ static bool try_qad_pin(struct i915_vma *vma, unsigned int flags) return pinned; }
-static int vma_get_pages(struct i915_vma *vma)
+static struct scatterlist * +rotate_pages(struct drm_i915_gem_object *obj, unsigned int offset,
unsigned int width, unsigned int height,unsigned int src_stride, unsigned int dst_stride,struct sg_table *st, struct scatterlist *sg){
int err = 0;bool pinned_pages = true;
unsigned int column, row;unsigned int src_idx;for (column = 0; column < width; column++) {unsigned int left;src_idx = src_stride * (height - 1) + column + offset;for (row = 0; row < height; row++) {st->nents++;/** We don't need the pages, but need to initialize* the entries so the sg list can be happily traversed.* The only thing we need are DMA addresses.*/sg_set_page(sg, NULL, I915_GTT_PAGE_SIZE, 0);sg_dma_address(sg) =i915_gem_object_get_dma_address(obj, src_idx);sg_dma_len(sg) = I915_GTT_PAGE_SIZE;sg = sg_next(sg);src_idx -= src_stride;}left = (dst_stride - height) * I915_GTT_PAGE_SIZE;if (!left)continue;st->nents++;/** The DE ignores the PTEs for the padding tiles, the sg entry* here is just a conenience to indicate how many padding PTEs* to insert at this spot.*/sg_set_page(sg, NULL, left, 0);sg_dma_address(sg) = 0;sg_dma_len(sg) = left;sg = sg_next(sg);}return sg;+}
+static noinline struct sg_table * +intel_rotate_pages(struct intel_rotation_info *rot_info,
struct drm_i915_gem_object *obj)+{
unsigned int size = intel_rotation_info_size(rot_info);struct drm_i915_private *i915 = to_i915(obj->base.dev);struct sg_table *st;struct scatterlist *sg;int ret = -ENOMEM;int i;/* Allocate target SG list. */st = kmalloc(sizeof(*st), GFP_KERNEL);if (!st)goto err_st_alloc;ret = sg_alloc_table(st, size, GFP_KERNEL);if (ret)goto err_sg_alloc;st->nents = 0;sg = st->sgl;for (i = 0 ; i < ARRAY_SIZE(rot_info->plane); i++)sg = rotate_pages(obj, rot_info->plane[i].offset,rot_info->plane[i].width, rot_info->plane[i].height,rot_info->plane[i].src_stride,rot_info->plane[i].dst_stride,st, sg);return st;+err_sg_alloc:
kfree(st);+err_st_alloc:
drm_dbg(&i915->drm, "Failed to create rotated mapping for object size %zu! (%ux%u tiles, %u pages)\n",obj->base.size, rot_info->plane[0].width,rot_info->plane[0].height, size);return ERR_PTR(ret);+}
+static struct scatterlist * +remap_pages(struct drm_i915_gem_object *obj,
unsigned int offset, unsigned int alignment_pad,unsigned int width, unsigned int height,unsigned int src_stride, unsigned int dst_stride,struct sg_table *st, struct scatterlist *sg)+{
unsigned int row;if (alignment_pad) {st->nents++;/** The DE ignores the PTEs for the padding tiles, the sg entry* here is just a convenience to indicate how many padding PTEs* to insert at this spot.*/sg_set_page(sg, NULL, alignment_pad * 4096, 0);sg_dma_address(sg) = 0;sg_dma_len(sg) = alignment_pad * 4096;sg = sg_next(sg);}for (row = 0; row < height; row++) {unsigned int left = width * I915_GTT_PAGE_SIZE;while (left) {dma_addr_t addr;unsigned int length;/** We don't need the pages, but need to initialize* the entries so the sg list can be happily traversed.* The only thing we need are DMA addresses.*/addr = i915_gem_object_get_dma_address_len(obj, offset, &length);length = min(left, length);st->nents++;sg_set_page(sg, NULL, length, 0);sg_dma_address(sg) = addr;sg_dma_len(sg) = length;sg = sg_next(sg);offset += length / I915_GTT_PAGE_SIZE;left -= length;}offset += src_stride - width;left = (dst_stride - width) * I915_GTT_PAGE_SIZE;if (!left)continue;st->nents++;/** The DE ignores the PTEs for the padding tiles, the sg entry* here is just a conenience to indicate how many padding PTEs* to insert at this spot.*/sg_set_page(sg, NULL, left, 0);sg_dma_address(sg) = 0;sg_dma_len(sg) = left;sg = sg_next(sg);}return sg;+}
+static noinline struct sg_table * +intel_remap_pages(struct intel_remapped_info *rem_info,
struct drm_i915_gem_object *obj)+{
unsigned int size = intel_remapped_info_size(rem_info);struct drm_i915_private *i915 = to_i915(obj->base.dev);struct sg_table *st;struct scatterlist *sg;unsigned int gtt_offset = 0;int ret = -ENOMEM;int i;/* Allocate target SG list. */st = kmalloc(sizeof(*st), GFP_KERNEL);if (!st)goto err_st_alloc;ret = sg_alloc_table(st, size, GFP_KERNEL);if (ret)goto err_sg_alloc;st->nents = 0;sg = st->sgl;for (i = 0 ; i < ARRAY_SIZE(rem_info->plane); i++) {unsigned int alignment_pad = 0;if (rem_info->plane_alignment)alignment_pad = ALIGN(gtt_offset, rem_info->plane_alignment) - gtt_offset;sg = remap_pages(obj,rem_info->plane[i].offset, alignment_pad,rem_info->plane[i].width, rem_info->plane[i].height,rem_info->plane[i].src_stride, rem_info->plane[i].dst_stride,st, sg);gtt_offset += alignment_pad +rem_info->plane[i].dst_stride * rem_info->plane[i].height;}i915_sg_trim(st);return st;+err_sg_alloc:
kfree(st);+err_st_alloc:
drm_dbg(&i915->drm, "Failed to create remapped mapping for object size %zu! (%ux%u tiles, %u pages)\n",obj->base.size, rem_info->plane[0].width,rem_info->plane[0].height, size);return ERR_PTR(ret);+}
+static noinline struct sg_table * +intel_partial_pages(const struct i915_ggtt_view *view,
struct drm_i915_gem_object *obj)+{
struct sg_table *st;struct scatterlist *sg, *iter;unsigned int count = view->partial.size;unsigned int offset;int ret = -ENOMEM;st = kmalloc(sizeof(*st), GFP_KERNEL);if (!st)goto err_st_alloc;ret = sg_alloc_table(st, count, GFP_KERNEL);if (ret)goto err_sg_alloc;iter = i915_gem_object_get_sg_dma(obj, view->partial.offset, &offset);GEM_BUG_ON(!iter);sg = st->sgl;st->nents = 0;do {unsigned int len;len = min(sg_dma_len(iter) - (offset << PAGE_SHIFT),count << PAGE_SHIFT);sg_set_page(sg, NULL, len, 0);sg_dma_address(sg) =sg_dma_address(iter) + (offset << PAGE_SHIFT);sg_dma_len(sg) = len;st->nents++;count -= len >> PAGE_SHIFT;if (count == 0) {sg_mark_end(sg);i915_sg_trim(st); /* Drop any unused tail entries. */return st;}sg = __sg_next(sg);iter = __sg_next(iter);offset = 0;} while (1);+err_sg_alloc:
kfree(st);+err_st_alloc:
return ERR_PTR(ret);+}
+static int +__i915_vma_get_pages(struct i915_vma *vma) +{
struct sg_table *pages;int ret;/** The vma->pages are only valid within the lifespan of the borrowed* obj->mm.pages. When the obj->mm.pages sg_table is regenerated, so* must be the vma->pages. A simple rule is that vma->pages must only* be accessed when the obj->mm.pages are pinned.*/GEM_BUG_ON(!i915_gem_object_has_pinned_pages(vma->obj));switch (vma->ggtt_view.type) {default:GEM_BUG_ON(vma->ggtt_view.type);fallthrough;case I915_GGTT_VIEW_NORMAL:pages = vma->obj->mm.pages;break;case I915_GGTT_VIEW_ROTATED:pages =intel_rotate_pages(&vma->ggtt_view.rotated, vma->obj);break;case I915_GGTT_VIEW_REMAPPED:pages =intel_remap_pages(&vma->ggtt_view.remapped, vma->obj);break;case I915_GGTT_VIEW_PARTIAL:pages = intel_partial_pages(&vma->ggtt_view, vma->obj);break;}ret = 0;/* gen6 ppgtt doesn't have backing pages, special-case it */if (IS_ERR(pages) && pages != ERR_PTR(-ENODEV)) {Where does this -ENODEV come from? AFAIK for the gen6 thing mm.pages = ZERO_SIZE_PTR. Also, just checking, I assume we always hit the VIEW_NORMAL for that?
ret = PTR_ERR(pages);pages = NULL;drm_err(&vma->vm->i915->drm,"Failed to get pages for VMA view type %u (%d)!\n",vma->ggtt_view.type, ret);Can we just return here?
}pages = xchg(&vma->pages, pages);/* did we race against a put_pages? */if (pages && pages != vma->obj->mm.pages) {sg_free_table(vma->pages);kfree(vma->pages);}What is this race exactly, can we add some more details here please? So we can more easily evaluate the lockless trickery here.
Ok, the lockless stuff just gets removed by the end of the series.