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 1a5975947e5b439095b0c4eed48331b1757c4158..3f9b6bd707d2e7ce81506cf2ea8a442ee9aa7c48 100644 (file)
--- 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");