From 08644db02d43478f802755903212f5ee506af73b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Joan=20Bruguera=20Mic=C3=B3?= <joanbrugueram@gmail.com>
Date: Sat, 6 Sep 2025 20:36:38 +0000
Subject: [PATCH] Fix build for Linux 6.18-rc1
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It's no longer required to use nth_page() when iterating pages within a
single scatterlist entry.

Note I believe this code path in `sg_advance` is currently unreachable:
It is only called from `get_userbuf_srtp`, passing in a scatterlist
copied from one created by `__get_userbuf`, which only generates
entries such that `sg->offset + sg->length <= PAGE_SIZE`.
On the other hand, this code path in `sg_advance` requires that
`sg->offset + sg->length > sg->offset + consumed >= PAGE_SIZE`.

See also: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f8f03eb5f0f91fddc9bb8563c7e82bd7d3ba1dd0
          https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ce00897b94bc5c62fab962625efcf1ab824d3688

Signed-off-by: Joan Bruguera Micó <joanbrugueram@gmail.com>
---
 util.c | 5 +++++
 1 file changed, 5 insertions(+)

--- a/util.c
+++ b/util.c
@@ -21,6 +21,7 @@
 
 #include <crypto/scatterwalk.h>
 #include <linux/scatterlist.h>
+#include <linux/version.h>
 #include "util.h"
 
 /* These were taken from Maxim Levitsky's patch to lkml.
@@ -44,8 +45,12 @@ struct scatterlist *sg_advance(struct sc
 	sg->length -= consumed;
 
 	if (sg->offset >= PAGE_SIZE) {
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(6, 18, 0))
+		struct page *page = sg_page(sg) + (sg->offset / PAGE_SIZE);
+#else
 		struct page *page =
 			nth_page(sg_page(sg), sg->offset / PAGE_SIZE);
+#endif
 		sg_set_page(sg, page, sg->length, sg->offset % PAGE_SIZE);
 	}
 
