staging: ion: fix common struct sg_table related issues
The Documentation/DMA-API-HOWTO.txt states that the dma_map_sg() function returns the number of the created entries in the DMA address space. However the subsequent calls to the dma_sync_sg_for_{device,cpu}() and dma_unmap_sg must be called with the original number of the entries passed to the dma_map_sg(). struct sg_table is a common structure used for describing a non-contiguous memory buffer, used commonly in the DRM and graphics subsystems. It consists of a scatterlist with memory pages and DMA addresses (sgl entry), as well as the number of scatterlist entries: CPU pages (orig_nents entry) and DMA mapped pages (nents entry). It turned out that it was a common mistake to misuse nents and orig_nents entries, calling DMA-mapping functions with a wrong number of entries or ignoring the number of mapped entries returned by the dma_map_sg() function. To avoid such issues, lets use a common dma-mapping wrappers operating directly on the struct sg_table objects and use scatterlist page iterators where possible. This, almost always, hides references to the nents and orig_nents entries, making the code robust, easier to follow and copy/paste safe. Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Link: https://lore.kernel.org/r/20200619103636.11974-31-m.szyprowski@samsung.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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@ -147,14 +147,14 @@ static struct sg_table *dup_sg_table(struct sg_table *table)
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if (!new_table)
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if (!new_table)
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return ERR_PTR(-ENOMEM);
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return ERR_PTR(-ENOMEM);
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ret = sg_alloc_table(new_table, table->nents, GFP_KERNEL);
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ret = sg_alloc_table(new_table, table->orig_nents, GFP_KERNEL);
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if (ret) {
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if (ret) {
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kfree(new_table);
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kfree(new_table);
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return ERR_PTR(-ENOMEM);
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return ERR_PTR(-ENOMEM);
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}
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}
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new_sg = new_table->sgl;
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new_sg = new_table->sgl;
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for_each_sg(table->sgl, sg, table->nents, i) {
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for_each_sgtable_sg(table, sg, i) {
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memcpy(new_sg, sg, sizeof(*sg));
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memcpy(new_sg, sg, sizeof(*sg));
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new_sg->dma_address = 0;
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new_sg->dma_address = 0;
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new_sg = sg_next(new_sg);
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new_sg = sg_next(new_sg);
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@ -224,12 +224,13 @@ static struct sg_table *ion_map_dma_buf(struct dma_buf_attachment *attachment,
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{
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{
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struct ion_dma_buf_attachment *a = attachment->priv;
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struct ion_dma_buf_attachment *a = attachment->priv;
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struct sg_table *table;
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struct sg_table *table;
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int ret;
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table = a->table;
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table = a->table;
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if (!dma_map_sg(attachment->dev, table->sgl, table->nents,
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ret = dma_map_sgtable(attachment->dev, table, direction, 0);
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direction))
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if (ret)
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return ERR_PTR(-ENOMEM);
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return ERR_PTR(ret);
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return table;
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return table;
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}
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}
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@ -238,7 +239,7 @@ static void ion_unmap_dma_buf(struct dma_buf_attachment *attachment,
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struct sg_table *table,
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struct sg_table *table,
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enum dma_data_direction direction)
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enum dma_data_direction direction)
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{
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{
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dma_unmap_sg(attachment->dev, table->sgl, table->nents, direction);
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dma_unmap_sgtable(attachment->dev, table, direction, 0);
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}
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}
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static int ion_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma)
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static int ion_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma)
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@ -296,10 +297,8 @@ static int ion_dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
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}
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}
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mutex_lock(&buffer->lock);
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mutex_lock(&buffer->lock);
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list_for_each_entry(a, &buffer->attachments, list) {
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list_for_each_entry(a, &buffer->attachments, list)
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dma_sync_sg_for_cpu(a->dev, a->table->sgl, a->table->nents,
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dma_sync_sgtable_for_cpu(a->dev, a->table, direction);
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direction);
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}
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unlock:
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unlock:
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mutex_unlock(&buffer->lock);
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mutex_unlock(&buffer->lock);
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@ -319,10 +318,8 @@ static int ion_dma_buf_end_cpu_access(struct dma_buf *dmabuf,
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}
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}
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mutex_lock(&buffer->lock);
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mutex_lock(&buffer->lock);
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list_for_each_entry(a, &buffer->attachments, list) {
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list_for_each_entry(a, &buffer->attachments, list)
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dma_sync_sg_for_device(a->dev, a->table->sgl, a->table->nents,
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dma_sync_sgtable_for_device(a->dev, a->table, direction);
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direction);
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}
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mutex_unlock(&buffer->lock);
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mutex_unlock(&buffer->lock);
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return 0;
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return 0;
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@ -20,8 +20,7 @@
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void *ion_heap_map_kernel(struct ion_heap *heap,
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void *ion_heap_map_kernel(struct ion_heap *heap,
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struct ion_buffer *buffer)
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struct ion_buffer *buffer)
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{
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{
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struct scatterlist *sg;
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struct sg_page_iter piter;
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int i, j;
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void *vaddr;
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void *vaddr;
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pgprot_t pgprot;
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pgprot_t pgprot;
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struct sg_table *table = buffer->sg_table;
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struct sg_table *table = buffer->sg_table;
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@ -38,14 +37,11 @@ void *ion_heap_map_kernel(struct ion_heap *heap,
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else
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else
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pgprot = pgprot_writecombine(PAGE_KERNEL);
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pgprot = pgprot_writecombine(PAGE_KERNEL);
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for_each_sg(table->sgl, sg, table->nents, i) {
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for_each_sgtable_page(table, &piter, 0) {
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int npages_this_entry = PAGE_ALIGN(sg->length) / PAGE_SIZE;
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BUG_ON(tmp - pages >= npages);
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struct page *page = sg_page(sg);
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*tmp++ = sg_page_iter_page(&piter);
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BUG_ON(i >= npages);
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for (j = 0; j < npages_this_entry; j++)
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*(tmp++) = page++;
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}
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}
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vaddr = vmap(pages, npages, VM_MAP, pgprot);
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vaddr = vmap(pages, npages, VM_MAP, pgprot);
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vfree(pages);
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vfree(pages);
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@ -64,32 +60,19 @@ void ion_heap_unmap_kernel(struct ion_heap *heap,
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int ion_heap_map_user(struct ion_heap *heap, struct ion_buffer *buffer,
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int ion_heap_map_user(struct ion_heap *heap, struct ion_buffer *buffer,
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struct vm_area_struct *vma)
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struct vm_area_struct *vma)
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{
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{
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struct sg_page_iter piter;
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struct sg_table *table = buffer->sg_table;
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struct sg_table *table = buffer->sg_table;
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unsigned long addr = vma->vm_start;
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unsigned long addr = vma->vm_start;
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unsigned long offset = vma->vm_pgoff * PAGE_SIZE;
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struct scatterlist *sg;
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int i;
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int ret;
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int ret;
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for_each_sg(table->sgl, sg, table->nents, i) {
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for_each_sgtable_page(table, &piter, vma->vm_pgoff) {
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struct page *page = sg_page(sg);
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struct page *page = sg_page_iter_page(&piter);
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unsigned long remainder = vma->vm_end - addr;
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unsigned long len = sg->length;
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if (offset >= sg->length) {
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ret = remap_pfn_range(vma, addr, page_to_pfn(page), PAGE_SIZE,
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offset -= sg->length;
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continue;
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} else if (offset) {
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page += offset / PAGE_SIZE;
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len = sg->length - offset;
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offset = 0;
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}
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len = min(len, remainder);
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ret = remap_pfn_range(vma, addr, page_to_pfn(page), len,
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vma->vm_page_prot);
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vma->vm_page_prot);
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if (ret)
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if (ret)
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return ret;
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return ret;
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addr += len;
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addr += PAGE_SIZE;
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if (addr >= vma->vm_end)
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if (addr >= vma->vm_end)
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return 0;
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return 0;
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}
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}
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@ -109,15 +92,14 @@ static int ion_heap_clear_pages(struct page **pages, int num, pgprot_t pgprot)
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return 0;
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return 0;
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}
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}
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static int ion_heap_sglist_zero(struct scatterlist *sgl, unsigned int nents,
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static int ion_heap_sglist_zero(struct sg_table *sgt, pgprot_t pgprot)
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pgprot_t pgprot)
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{
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{
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int p = 0;
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int p = 0;
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int ret = 0;
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int ret = 0;
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struct sg_page_iter piter;
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struct sg_page_iter piter;
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struct page *pages[32];
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struct page *pages[32];
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for_each_sg_page(sgl, &piter, nents, 0) {
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for_each_sgtable_page(sgt, &piter, 0) {
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pages[p++] = sg_page_iter_page(&piter);
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pages[p++] = sg_page_iter_page(&piter);
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if (p == ARRAY_SIZE(pages)) {
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if (p == ARRAY_SIZE(pages)) {
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ret = ion_heap_clear_pages(pages, p, pgprot);
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ret = ion_heap_clear_pages(pages, p, pgprot);
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@ -142,7 +124,7 @@ int ion_heap_buffer_zero(struct ion_buffer *buffer)
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else
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else
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pgprot = pgprot_writecombine(PAGE_KERNEL);
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pgprot = pgprot_writecombine(PAGE_KERNEL);
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return ion_heap_sglist_zero(table->sgl, table->nents, pgprot);
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return ion_heap_sglist_zero(table, pgprot);
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}
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}
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void ion_heap_freelist_add(struct ion_heap *heap, struct ion_buffer *buffer)
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void ion_heap_freelist_add(struct ion_heap *heap, struct ion_buffer *buffer)
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@ -162,7 +162,7 @@ static void ion_system_heap_free(struct ion_buffer *buffer)
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if (!(buffer->private_flags & ION_PRIV_FLAG_SHRINKER_FREE))
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if (!(buffer->private_flags & ION_PRIV_FLAG_SHRINKER_FREE))
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ion_heap_buffer_zero(buffer);
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ion_heap_buffer_zero(buffer);
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for_each_sg(table->sgl, sg, table->nents, i)
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for_each_sgtable_sg(table, sg, i)
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free_buffer_page(sys_heap, buffer, sg_page(sg));
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free_buffer_page(sys_heap, buffer, sg_page(sg));
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sg_free_table(table);
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sg_free_table(table);
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kfree(table);
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kfree(table);
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