FAILED: patch "[PATCH] drm/i915/dmabuf: fix sg_table handling in map_dma_buf" failed to apply to 4.9-stable tree

The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

Possible dependencies:

28d52f99bbca ("drm/i915/dmabuf: fix sg_table handling in map_dma_buf") 10be98a77c55 ("drm/i915: Move more GEM objects under gem/")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 28d52f99bbca7227008cf580c9194c9b3516968e Mon Sep 17 00:00:00 2001
From: Matthew Auld <[email protected]>
Date: Fri, 28 Oct 2022 16:50:26 +0100
Subject: [PATCH] drm/i915/dmabuf: fix sg_table handling in map_dma_buf
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

We need to iterate over the original entries here for the sg_table, pulling out the struct page for each one, to be remapped. However currently this incorrectly iterates over the final dma mapped entries, which is likely just one gigantic sg entry if the iommu is enabled, leading to us only mapping the first struct page (and any physically contiguous pages following it), even if there is potentially lots more data to follow.

index f5062d0c6333..824971a1ceec 100644
@@ -40,13 +40,13 @@ static struct sg_table *i915_gem_map_dma_buf(struct dma_buf_attachment *attachme
 		goto err;
 	}
 
-	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);