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[172.10.233.147]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2d613b2048fsm8379942a91.54.2024.08.25.15.42.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 25 Aug 2024 15:42:46 -0700 (PDT) Date: Sun, 25 Aug 2024 15:42:45 -0700 (PDT) From: Hugh Dickins To: Andrew Morton cc: "Kirill A. Shutemov" , Baolin Wang , Hugh Dickins , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH] mm: shmem: fix minor off-by-one in shrinkable calculation Message-ID: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" There has been a long-standing and very minor off-by-one, where shmem_get_folio_gfp() decides if a large folio extends beyond i_size far enough to leave a page or more for freeing later under pressure. This is not something needed for stable: but it will be proportionately more significant as support for smaller large folios is added, and is best fixed before duplicating the check in other places. Fixes: 779750d20b93 ("shmem: split huge pages beyond i_size under memory pr= essure") Signed-off-by: Hugh Dickins Reviewed-by: Baolin Wang Reviewed-by: David Hildenbrand --- mm/shmem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/shmem.c b/mm/shmem.c index 85e3bd3e709e..37c300f69baf 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2326,7 +2326,7 @@ static int shmem_get_folio_gfp(struct inode *inode, p= goff_t index, alloced =3D true; if (folio_test_large(folio) && DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE) < - folio_next_index(folio) - 1) { + folio_next_index(folio)) { struct shmem_sb_info *sbinfo =3D SHMEM_SB(inode->i_sb); struct shmem_inode_info *info =3D SHMEM_I(inode); /* --=20 2.35.3