Re: [Intel-gfx] [RFC 06/17] drm: i915: fix sg_table nents vs. orig_nents misuse
Hi
On 28.04.2020 16:27, Tvrtko Ursulin wrote:
>
> On 28/04/2020 14:19, Marek Szyprowski wrote:
>> The Documentation/DMA-API-HOWTO.txt states that dma_map_sg returns the
>> numer of the created entries in the DMA address space. However the
>> subsequent calls to dma_sync_sg_for_{device,cpu} and dma_unmap_sg
>> must be
>> called with the original number of entries passed to dma_map_sg. The
>> sg_table->nents in turn holds the result of the dma_map_sg call as
>> stated
>> in include/linux/scatterlist.h. Adapt the code to obey those rules.
>>
>> Signed-off-by: Marek Szyprowski
>> ---
>> drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c | 13 +++--
>> drivers/gpu/drm/i915/gem/i915_gem_internal.c | 4 ++--
>> drivers/gpu/drm/i915/gem/i915_gem_region.c | 4 ++--
>> drivers/gpu/drm/i915/gem/i915_gem_shmem.c | 5 +++--
>> drivers/gpu/drm/i915/gem/selftests/huge_pages.c | 10 +-
>> drivers/gpu/drm/i915/gem/selftests/mock_dmabuf.c | 5 +++--
>> drivers/gpu/drm/i915/gt/intel_ggtt.c | 12 ++--
>> drivers/gpu/drm/i915/i915_gem_gtt.c | 12 +++-
>> drivers/gpu/drm/i915/i915_scatterlist.c | 4 ++--
>> drivers/gpu/drm/i915/selftests/scatterlist.c | 8
>> 10 files changed, 41 insertions(+), 36 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
>> b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
>> index 7db5a79..d829852 100644
>> --- a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
>> +++ b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
>> @@ -36,21 +36,22 @@ static struct sg_table
>> *i915_gem_map_dma_buf(struct dma_buf_attachment *attachme
>> goto err_unpin_pages;
>> }
>> - ret = sg_alloc_table(st, obj->mm.pages->nents, GFP_KERNEL);
>> + ret = sg_alloc_table(st, obj->mm.pages->orig_nents, GFP_KERNEL);
>> if (ret)
>> goto err_free;
>> src = obj->mm.pages->sgl;
>> dst = st->sgl;
>> - for (i = 0; i < obj->mm.pages->nents; i++) {
>> + for (i = 0; i < obj->mm.pages->orig_nents; i++) {
>> sg_set_page(dst, sg_page(src), src->length, 0);
>> dst = sg_next(dst);
>> src = sg_next(src);
>> }
>> - if (!dma_map_sg_attrs(attachment->dev,
>> - st->sgl, st->nents, dir,
>> - DMA_ATTR_SKIP_CPU_SYNC)) {
>> + st->nents = dma_map_sg_attrs(attachment->dev,
>> + st->sgl, st->orig_nents, dir,
>> + DMA_ATTR_SKIP_CPU_SYNC);
>> + if (!st->nents) {
>> ret = -ENOMEM;
>> goto err_free_sg;
>> }
>> @@ -74,7 +75,7 @@ static void i915_gem_unmap_dma_buf(struct
>> dma_buf_attachment *attachment,
>> struct drm_i915_gem_object *obj =
>> dma_buf_to_obj(attachment->dmabuf);
>> dma_unmap_sg_attrs(attachment->dev,
>> - sg->sgl, sg->nents, dir,
>> + sg->sgl, sg->orig_nents, dir,
>> DMA_ATTR_SKIP_CPU_SYNC);
>> sg_free_table(sg);
>> kfree(sg);
>> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_internal.c
>> b/drivers/gpu/drm/i915/gem/i915_gem_internal.c
>> index cbbff81..a8ebfdd 100644
>> --- a/drivers/gpu/drm/i915/gem/i915_gem_internal.c
>> +++ b/drivers/gpu/drm/i915/gem/i915_gem_internal.c
>> @@ -73,7 +73,7 @@ static int
>> i915_gem_object_get_pages_internal(struct drm_i915_gem_object *obj)
>> }
>> sg = st->sgl;
>> - st->nents = 0;
>> + st->nents = st->orig_nents = 0;
>> sg_page_sizes = 0;
>> do {
>> @@ -94,7 +94,7 @@ static int
>> i915_gem_object_get_pages_internal(struct drm_i915_gem_object *obj)
>> sg_set_page(sg, page, PAGE_SIZE << order, 0);
>> sg_page_sizes |= PAGE_SIZE << order;
>> - st->nents++;
>> + st->nents = st->orig_nents = st->nents + 1;
>> npages -= 1 << order;
>> if (!npages) {
>> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_region.c
>> b/drivers/gpu/drm/i915/gem/i915_gem_region.c
>> index 1515384..58ca560 100644
>> --- a/drivers/gpu/drm/i915/gem/i915_gem_region.c
>> +++ b/drivers/gpu/drm/i915/gem/i915_gem_region.c
>> @@ -53,7 +53,7 @@
>> GEM_BUG_ON(list_empty(blocks));
>> sg = st->sgl;
>> - st->nents = 0;
>> + st->nents = st->orig_nents = 0;
>> sg_page_sizes = 0;
>> prev_end = (resource_size_t)-1;
>> @@ -78,7 +78,7 @@
>> sg->length = block_size;
>> - st->nents++;
>> + st->nents = st->orig_nents = st->nents + 1;
>> } else {
>> sg->length += block_size;
>> sg_dma_len(sg) += block_size;
>> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
>> b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
>> index 5d5d7ee..851a732 100644
>> --- a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
>> +++ b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
>> @@ -80,7 +80,7 @@ static int shmem_get_pages(struct
>> drm_i915_gem_object *obj)
>> noreclaim |= __GFP_NORETRY
Re: [Intel-gfx] [RFC 06/17] drm: i915: fix sg_table nents vs. orig_nents misuse
On 28/04/2020 14:19, Marek Szyprowski wrote:
The Documentation/DMA-API-HOWTO.txt states that dma_map_sg returns the
numer of the created entries in the DMA address space. However the
subsequent calls to dma_sync_sg_for_{device,cpu} and dma_unmap_sg must be
called with the original number of entries passed to dma_map_sg. The
sg_table->nents in turn holds the result of the dma_map_sg call as stated
in include/linux/scatterlist.h. Adapt the code to obey those rules.
Signed-off-by: Marek Szyprowski
---
drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c | 13 +++--
drivers/gpu/drm/i915/gem/i915_gem_internal.c | 4 ++--
drivers/gpu/drm/i915/gem/i915_gem_region.c | 4 ++--
drivers/gpu/drm/i915/gem/i915_gem_shmem.c| 5 +++--
drivers/gpu/drm/i915/gem/selftests/huge_pages.c | 10 +-
drivers/gpu/drm/i915/gem/selftests/mock_dmabuf.c | 5 +++--
drivers/gpu/drm/i915/gt/intel_ggtt.c | 12 ++--
drivers/gpu/drm/i915/i915_gem_gtt.c | 12 +++-
drivers/gpu/drm/i915/i915_scatterlist.c | 4 ++--
drivers/gpu/drm/i915/selftests/scatterlist.c | 8
10 files changed, 41 insertions(+), 36 deletions(-)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
index 7db5a79..d829852 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
@@ -36,21 +36,22 @@ static struct sg_table *i915_gem_map_dma_buf(struct
dma_buf_attachment *attachme
goto err_unpin_pages;
}
- ret = sg_alloc_table(st, obj->mm.pages->nents, GFP_KERNEL);
+ ret = sg_alloc_table(st, obj->mm.pages->orig_nents, GFP_KERNEL);
if (ret)
goto err_free;
src = obj->mm.pages->sgl;
dst = st->sgl;
- for (i = 0; i < obj->mm.pages->nents; i++) {
+ for (i = 0; i < obj->mm.pages->orig_nents; i++) {
sg_set_page(dst, sg_page(src), src->length, 0);
dst = sg_next(dst);
src = sg_next(src);
}
- if (!dma_map_sg_attrs(attachment->dev,
- st->sgl, st->nents, dir,
- DMA_ATTR_SKIP_CPU_SYNC)) {
+ st->nents = dma_map_sg_attrs(attachment->dev,
+st->sgl, st->orig_nents, dir,
+DMA_ATTR_SKIP_CPU_SYNC);
+ if (!st->nents) {
ret = -ENOMEM;
goto err_free_sg;
}
@@ -74,7 +75,7 @@ static void i915_gem_unmap_dma_buf(struct dma_buf_attachment
*attachment,
struct drm_i915_gem_object *obj = dma_buf_to_obj(attachment->dmabuf);
dma_unmap_sg_attrs(attachment->dev,
- sg->sgl, sg->nents, dir,
+ sg->sgl, sg->orig_nents, dir,
DMA_ATTR_SKIP_CPU_SYNC);
sg_free_table(sg);
kfree(sg);
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_internal.c
b/drivers/gpu/drm/i915/gem/i915_gem_internal.c
index cbbff81..a8ebfdd 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_internal.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_internal.c
@@ -73,7 +73,7 @@ static int i915_gem_object_get_pages_internal(struct
drm_i915_gem_object *obj)
}
sg = st->sgl;
- st->nents = 0;
+ st->nents = st->orig_nents = 0;
sg_page_sizes = 0;
do {
@@ -94,7 +94,7 @@ static int i915_gem_object_get_pages_internal(struct
drm_i915_gem_object *obj)
sg_set_page(sg, page, PAGE_SIZE << order, 0);
sg_page_sizes |= PAGE_SIZE << order;
- st->nents++;
+ st->nents = st->orig_nents = st->nents + 1;
npages -= 1 << order;
if (!npages) {
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_region.c
b/drivers/gpu/drm/i915/gem/i915_gem_region.c
index 1515384..58ca560 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_region.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_region.c
@@ -53,7 +53,7 @@
GEM_BUG_ON(list_empty(blocks));
sg = st->sgl;
- st->nents = 0;
+ st->nents = st->orig_nents = 0;
sg_page_sizes = 0;
prev_end = (resource_size_t)-1;
@@ -78,7 +78,7 @@
sg->length = block_size;
- st->nents++;
+ st->nents = st->orig_nents = st->nents + 1;
} else {
sg->length += block_size;
sg_dma_len(sg) += block_size;
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
index 5d5d7ee..851a732 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
@@ -80,7 +80,7 @@ static int shmem_get_pages(struct drm_i915_gem_object *obj)
noreclaim |= __GFP_NORETRY | __GFP_NOWARN;
sg = st->sgl;
- st->nents = 0;
+ st->nents = st->orig_nents = 0;
sg_page_sizes = 0;
for (i = 0; i < page_count; i++) {
