linux-kernel - [PATCH 4/4] filemap: Check address range in filemap_map_folio

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Date:   Tue, 30 May 2023 16:07:31 +0800
From:   Yin Fengwei <fengwei.yin@...el.com>
To:     willy@...radead.org, ryan.roberts@....com,
        linux-arch@...r.kernel.org, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org
Cc:     fengwei.yin@...el.com
Subject: [PATCH 4/4] filemap: Check address range in filemap_map_folio_range()

With filemap_map_folio_range(), the addr is updated with range
also. Address range checking is needed to make sure correct
return value (VM_FAULT_NOPAGE) if vmf->address is handled.

Signed-off-by: Yin Fengwei <fengwei.yin@...el.com>
---
 mm/filemap.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/mm/filemap.c b/mm/filemap.c
index fdb3e0a339b3..0f4baba1cd31 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -3488,15 +3488,15 @@ static vm_fault_t filemap_map_folio_range(struct vm_fault *vmf,
 		if (!pte_none(vmf->pte[count]))
 			goto skip;
 
-		if (vmf->address == addr)
-			ret = VM_FAULT_NOPAGE;
-
 		count++;
 		continue;
 skip:
 		if (count) {
 			set_pte_range(vmf, folio, page, count, addr);
 			folio_ref_add(folio, count);
+			if ((vmf->address < (addr + count * PAGE_SIZE)) &&
+					(vmf->address >= addr))
+				ret = VM_FAULT_NOPAGE;
 		}
 
 		count++;
@@ -3509,6 +3509,9 @@ static vm_fault_t filemap_map_folio_range(struct vm_fault *vmf,
 	if (count) {
 		set_pte_range(vmf, folio, page, count, addr);
 		folio_ref_add(folio, count);
+		if ((vmf->address < (addr + count * PAGE_SIZE)) &&
+				(vmf->address >= addr))
+			ret = VM_FAULT_NOPAGE;
 	}
 
 	vmf->pte = old_ptep;
-- 
2.30.2