On Mon, Nov 19, 2012 at 3:14 PM, Kyungmin Park <kmpark at infradead.org> wrote:
> Hi,
>
> On 11/15/12, Prathyush K <prathyush.k at samsung.com> wrote:
> > The 'pages' structure is not required since we can use the 'sgt'. Even
> for
> > CONTIG buffers, a SGT is created (which will have just one sgl). This SGT
> > can be used during mmap instead of 'pages'. The 'page_size' element of
> the
> > structure is also not used anywhere and is removed.
> > This patch also fixes a memory leak where the 'pages' structure was being
> > allocated during gem buffer allocation but not being freed during
> > deallocate.
> >
> > Signed-off-by: Prathyush K <prathyush.k at samsung.com>
> > ---
> > drivers/gpu/drm/exynos/exynos_drm_buf.c | 20 --------------
> > drivers/gpu/drm/exynos/exynos_drm_buf.h | 4 +-
> > drivers/gpu/drm/exynos/exynos_drm_dmabuf.c | 3 +-
> > drivers/gpu/drm/exynos/exynos_drm_gem.c | 39
> > +++++++++++----------------
> > drivers/gpu/drm/exynos/exynos_drm_gem.h | 4 ---
> > 5 files changed, 19 insertions(+), 51 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/exynos/exynos_drm_buf.c
> > b/drivers/gpu/drm/exynos/exynos_drm_buf.c
> > index 48c5896..72bf97b 100644
> > --- a/drivers/gpu/drm/exynos/exynos_drm_buf.c
> > +++ b/drivers/gpu/drm/exynos/exynos_drm_buf.c
> > @@ -34,8 +34,6 @@ static int lowlevel_buffer_allocate(struct drm_device
> > *dev,
> > unsigned int flags, struct exynos_drm_gem_buf *buf)
> > {
> > int ret = 0;
> > - unsigned int npages, i = 0;
> > - struct scatterlist *sgl;
> > enum dma_attr attr = DMA_ATTR_FORCE_CONTIGUOUS;
> >
> > DRM_DEBUG_KMS("%s\n", __FILE__);
> > @@ -73,22 +71,6 @@ static int lowlevel_buffer_allocate(struct drm_device
> > *dev,
> > goto err_free_sgt;
> > }
> >
> > - npages = buf->sgt->nents;
> > -
> > - buf->pages = kzalloc(sizeof(struct page) * npages, GFP_KERNEL);
> > - if (!buf->pages) {
> > - DRM_ERROR("failed to allocate pages.\n");
> > - ret = -ENOMEM;
> > - goto err_free_table;
> > - }
> > -
> > - sgl = buf->sgt->sgl;
> > - while (i < npages) {
> > - buf->pages[i] = sg_page(sgl);
> > - sgl = sg_next(sgl);
> > - i++;
> > - }
> > -
> > DRM_DEBUG_KMS("vaddr(0x%lx), dma_addr(0x%lx), size(0x%lx)\n",
> > (unsigned long)buf->kvaddr,
> > (unsigned long)buf->dma_addr,
> > @@ -96,8 +78,6 @@ static int lowlevel_buffer_allocate(struct drm_device
> > *dev,
> >
> > return ret;
> >
> > -err_free_table:
> > - sg_free_table(buf->sgt);
> > err_free_sgt:
> > kfree(buf->sgt);
> > buf->sgt = NULL;
> > diff --git a/drivers/gpu/drm/exynos/exynos_drm_buf.h
> > b/drivers/gpu/drm/exynos/exynos_drm_buf.h
> > index 3388e4e..25cf162 100644
> > --- a/drivers/gpu/drm/exynos/exynos_drm_buf.h
> > +++ b/drivers/gpu/drm/exynos/exynos_drm_buf.h
> > @@ -34,12 +34,12 @@ struct exynos_drm_gem_buf *exynos_drm_init_buf(struct
> > drm_device *dev,
> > void exynos_drm_fini_buf(struct drm_device *dev,
> > struct exynos_drm_gem_buf *buffer);
> >
> > -/* allocate physical memory region and setup sgt and pages. */
> > +/* allocate physical memory region and setup sgt. */
> > int exynos_drm_alloc_buf(struct drm_device *dev,
> > struct exynos_drm_gem_buf *buf,
> > unsigned int flags);
> >
> > -/* release physical memory region, sgt and pages. */
> > +/* release physical memory region, and sgt. */
> > void exynos_drm_free_buf(struct drm_device *dev,
> > unsigned int flags,
> > struct exynos_drm_gem_buf *buffer);
> > diff --git a/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
> > b/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
> > index b98da30..615a049 100644
> > --- a/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
> > +++ b/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
> > @@ -93,8 +93,7 @@ static struct sg_table *
> > goto err_unlock;
> > }
> >
> > - DRM_DEBUG_PRIME("buffer size = 0x%lx page_size = 0x%lx\n",
> > - buf->size, buf->page_size);
> > + DRM_DEBUG_PRIME("buffer size = 0x%lx\n", buf->size);
> >
> > err_unlock:
> > mutex_unlock(&dev->struct_mutex);
> > diff --git a/drivers/gpu/drm/exynos/exynos_drm_gem.c
> > b/drivers/gpu/drm/exynos/exynos_drm_gem.c
> > index 50d73f1..40999ac 100644
> > --- a/drivers/gpu/drm/exynos/exynos_drm_gem.c
> > +++ b/drivers/gpu/drm/exynos/exynos_drm_gem.c
> > @@ -99,34 +99,27 @@ static int exynos_drm_gem_map_buf(struct
> drm_gem_object
> > *obj,
> > unsigned long pfn;
> > int i;
> >
> > - if (exynos_gem_obj->flags & EXYNOS_BO_NONCONTIG) {
> > - if (!buf->sgt)
> > - return -EINTR;
> > -
> > - sgl = buf->sgt->sgl;
> > - for_each_sg(buf->sgt->sgl, sgl, buf->sgt->nents, i) {
> > - if (!sgl) {
> > - DRM_ERROR("invalid SG table\n");
> > - return -EINTR;
> > - }
> > - if (page_offset < (sgl->length >> PAGE_SHIFT))
> > - break;
> > - page_offset -= (sgl->length >> PAGE_SHIFT);
> > - }
> > -
> > - if (i >= buf->sgt->nents) {
> > - DRM_ERROR("invalid page offset\n");
> > - return -EINVAL;
> > - }
> > + if (!buf->sgt)
> > + return -EINTR;
> >
> > - pfn = __phys_to_pfn(sg_phys(sgl)) + page_offset;
> > - } else {
> > - if (!buf->pages)
> > + sgl = buf->sgt->sgl;
> > + for_each_sg(buf->sgt->sgl, sgl, buf->sgt->nents, i) {
> > + if (!sgl) {
> It's never happned by for_each_sg definition.
>
> Agreed. This normally should never happen.
But actually this is existing code. I have not changed this.
I had just moved the above code from inside a 'if else' condition to
outside.
> > + DRM_ERROR("invalid SG table\n");
> > return -EINTR;
> > + }
> > + if (page_offset < (sgl->length >> PAGE_SHIFT))
> > + break;
> > + page_offset -= (sgl->length >> PAGE_SHIFT);
> > + }
> >
> > - pfn = page_to_pfn(buf->pages[0]) + page_offset;
> > + if (i >= buf->sgt->nents) {
> ditto. IOW it's dead code.
>
> Again, this is also existing code.
But this error can actually happen if the page offset is not valid.
e.g. if page_offset > (buf_size >> PAGE_SHIFT)
In this case, the loop 'for_each_sg' will never break in between
and 'i' will be equal to nents. This check will return error which
is correct.
Thanks for reviewing. If required, I can post another patch
to remove the first redundant check. But I don't think it should
be part of this patch.
> Thank you,
> Kyungmin Park
> > + DRM_ERROR("invalid page offset\n");
> > + return -EINVAL;
> > }
> >
> > + pfn = __phys_to_pfn(sg_phys(sgl)) + page_offset;
> > +
> > return vm_insert_mixed(vma, f_vaddr, pfn);
> > }
> >
> > diff --git a/drivers/gpu/drm/exynos/exynos_drm_gem.h
> > b/drivers/gpu/drm/exynos/exynos_drm_gem.h
> > index 83d21ef..3600b3b 100644
> > --- a/drivers/gpu/drm/exynos/exynos_drm_gem.h
> > +++ b/drivers/gpu/drm/exynos/exynos_drm_gem.h
> > @@ -39,8 +39,6 @@
> > * - this address could be physical address without IOMMU and
> > * device address with IOMMU.
> > * @sgt: sg table to transfer page data.
> > - * @pages: contain all pages to allocated memory region.
> > - * @page_size: could be 4K, 64K or 1MB.
> > * @size: size of allocated memory region.
> > */
> > struct exynos_drm_gem_buf {
> > @@ -48,8 +46,6 @@ struct exynos_drm_gem_buf {
> > dma_addr_t dma_addr;
> > struct dma_attrs dma_attrs;
> > struct sg_table *sgt;
> > - struct page **pages;
> > - unsigned long page_size;
> > unsigned long size;
> > };
> >
> > --
> > 1.7.0.4
> >
> > _______________________________________________
> > dri-devel mailing list
> > dri-devel at lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/dri-devel
> >
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