FAILED: patch "[PATCH] riscv: fix set_huge_pte_at() for NAPOT mappings when a swap" failed to apply to 6.5-stable tree

[<gregkh@xxxxxxxxxxxxxxxxxxx>]

The patch below does not apply to the 6.5-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 <stable@xxxxxxxxxxxxxxx>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.5.y
git checkout FETCH_HEAD
git cherry-pick -x 1de195dd0e05d9cba43dec16f83d4ee32af94dd2
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@xxxxxxxxxxxxxxx>' --in-reply-to '2023110127-chip-surfacing-4583@gregkh' --subject-prefix 'PATCH 6.5.y' HEAD^..

Possible dependencies:

1de195dd0e05 ("riscv: fix set_huge_pte_at() for NAPOT mappings when a swap entry is set")

thanks,

greg k-h

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

>From 1de195dd0e05d9cba43dec16f83d4ee32af94dd2 Mon Sep 17 00:00:00 2001
From: Alexandre Ghiti <alexghiti@xxxxxxxxxxxx>
Date: Thu, 28 Sep 2023 17:18:46 +0200
Subject: [PATCH] riscv: fix set_huge_pte_at() for NAPOT mappings when a swap
 entry is set

We used to determine the number of page table entries to set for a NAPOT
hugepage by using the pte value which actually fails when the pte to set
is a swap entry.

So take advantage of a recent fix for arm64 reported in [1] which
introduces the size of the mapping as an argument of set_huge_pte_at(): we
can then use this size to compute the number of page table entries to set
for a NAPOT region.

Link: https://lkml.kernel.org/r/20230928151846.8229-3-alexghiti@xxxxxxxxxxxx
Fixes: 82a1a1f3bfb6 ("riscv: mm: support Svnapot in hugetlb page")
Signed-off-by: Alexandre Ghiti <alexghiti@xxxxxxxxxxxx>
Reported-by: Ryan Roberts <ryan.roberts@xxxxxxx>
Closes: https://lore.kernel.org/linux-arm-kernel/20230922115804.2043771-1-ryan.roberts@xxxxxxx/ [1]
Reviewed-by: Andrew Jones <ajones@xxxxxxxxxxxxxxxx>
Cc: Albert Ou <aou@xxxxxxxxxxxxxxxxx>
Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx>
Cc: Paul Walmsley <paul.walmsley@xxxxxxxxxx>
Cc: Qinglin Pan <panqinglin2020@xxxxxxxxxxx>
Cc: Conor Dooley <conor@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>

diff --git a/arch/riscv/mm/hugetlbpage.c b/arch/riscv/mm/hugetlbpage.c
index e4a2ace92dbe..b52f0210481f 100644
--- a/arch/riscv/mm/hugetlbpage.c
+++ b/arch/riscv/mm/hugetlbpage.c
@@ -183,15 +183,22 @@ void set_huge_pte_at(struct mm_struct *mm,
 		     pte_t pte,
 		     unsigned long sz)
 {
+	unsigned long hugepage_shift;
 	int i, pte_num;
 
-	if (!pte_napot(pte)) {
-		set_pte_at(mm, addr, ptep, pte);
-		return;
-	}
+	if (sz >= PGDIR_SIZE)
+		hugepage_shift = PGDIR_SHIFT;
+	else if (sz >= P4D_SIZE)
+		hugepage_shift = P4D_SHIFT;
+	else if (sz >= PUD_SIZE)
+		hugepage_shift = PUD_SHIFT;
+	else if (sz >= PMD_SIZE)
+		hugepage_shift = PMD_SHIFT;
+	else
+		hugepage_shift = PAGE_SHIFT;
 
-	pte_num = napot_pte_num(napot_cont_order(pte));
-	for (i = 0; i < pte_num; i++, ptep++, addr += PAGE_SIZE)
+	pte_num = sz >> hugepage_shift;
+	for (i = 0; i < pte_num; i++, ptep++, addr += (1 << hugepage_shift))
 		set_pte_at(mm, addr, ptep, pte);
 }