From: Miao Wang <shankerwangmiao@gmail.com>
Date: Tue, 13 Aug 2024 17:12:13 +0000 (+0800)
Subject: mm: vmalloc: add optimization hint on page existence check
X-Git-Tag: v6.12-rc1~115^2~318
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=6963f00813f49375360544fe923e62f2070601af;p=thirdparty%2Fkernel%2Flinux.git

mm: vmalloc: add optimization hint on page existence check

In commit 21e516b913c1 ("mm: vmalloc: dump page owner info if page is
already mapped"), a BUG_ON macro was changed into an if statement, where
the compiler optimization hint introduced in the BUG_ON macro was removed
along with this change.  This patch adds back the hint.

Link: https://lkml.kernel.org/r/20240814-fix_vmap_unlikely-v1-1-cd7954775f12@gmail.com
Fixes: 21e516b913c1 ("mm: vmalloc: dump page owner info if page is already mapped")
Signed-off-by: Miao Wang <shankerwangmiao@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Hariom Panthi <hariom1.p@samsung.com>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 884e21fed28f1..dfa8f09e7e9dd 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -105,7 +105,7 @@ static int vmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
 	if (!pte)
 		return -ENOMEM;
 	do {
-		if (!pte_none(ptep_get(pte))) {
+		if (unlikely(!pte_none(ptep_get(pte)))) {
 			if (pfn_valid(pfn)) {
 				page = pfn_to_page(pfn);
 				dump_page(page, "remapping already mapped page");