| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <20260126164445.11867-5-kalyazin@amazon.com>
Date: Mon, 26 Jan 2026 16:47:34 +0000
From: "Kalyazin, Nikita" <kalyazin@...zon.co.uk>
To: "kvm@...r.kernel.org" <kvm@...r.kernel.org>, "linux-doc@...r.kernel.org"
<linux-doc@...r.kernel.org>, "linux-kernel@...r.kernel.org"
<linux-kernel@...r.kernel.org>, "linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>, "kvmarm@...ts.linux.dev"
<kvmarm@...ts.linux.dev>, "linux-fsdevel@...r.kernel.org"
<linux-fsdevel@...r.kernel.org>, "linux-mm@...ck.org" <linux-mm@...ck.org>,
"bpf@...r.kernel.org" <bpf@...r.kernel.org>,
"linux-kselftest@...r.kernel.org" <linux-kselftest@...r.kernel.org>,
"kernel@...0n.name" <kernel@...0n.name>, "linux-riscv@...ts.infradead.org"
<linux-riscv@...ts.infradead.org>, "linux-s390@...r.kernel.org"
<linux-s390@...r.kernel.org>, "loongarch@...ts.linux.dev"
<loongarch@...ts.linux.dev>
CC: "pbonzini@...hat.com" <pbonzini@...hat.com>, "corbet@....net"
<corbet@....net>, "maz@...nel.org" <maz@...nel.org>, "oupton@...nel.org"
<oupton@...nel.org>, "joey.gouly@....com" <joey.gouly@....com>,
"suzuki.poulose@....com" <suzuki.poulose@....com>, "yuzenghui@...wei.com"
<yuzenghui@...wei.com>, "catalin.marinas@....com" <catalin.marinas@....com>,
"will@...nel.org" <will@...nel.org>, "seanjc@...gle.com" <seanjc@...gle.com>,
"tglx@...nel.org" <tglx@...nel.org>, "mingo@...hat.com" <mingo@...hat.com>,
"bp@...en8.de" <bp@...en8.de>, "dave.hansen@...ux.intel.com"
<dave.hansen@...ux.intel.com>, "x86@...nel.org" <x86@...nel.org>,
"hpa@...or.com" <hpa@...or.com>, "luto@...nel.org" <luto@...nel.org>,
"peterz@...radead.org" <peterz@...radead.org>, "willy@...radead.org"
<willy@...radead.org>, "akpm@...ux-foundation.org"
<akpm@...ux-foundation.org>, "david@...nel.org" <david@...nel.org>,
"lorenzo.stoakes@...cle.com" <lorenzo.stoakes@...cle.com>, "vbabka@...e.cz"
<vbabka@...e.cz>, "rppt@...nel.org" <rppt@...nel.org>, "surenb@...gle.com"
<surenb@...gle.com>, "mhocko@...e.com" <mhocko@...e.com>, "ast@...nel.org"
<ast@...nel.org>, "daniel@...earbox.net" <daniel@...earbox.net>,
"andrii@...nel.org" <andrii@...nel.org>, "martin.lau@...ux.dev"
<martin.lau@...ux.dev>, "eddyz87@...il.com" <eddyz87@...il.com>,
"song@...nel.org" <song@...nel.org>, "yonghong.song@...ux.dev"
<yonghong.song@...ux.dev>, "john.fastabend@...il.com"
<john.fastabend@...il.com>, "kpsingh@...nel.org" <kpsingh@...nel.org>,
"sdf@...ichev.me" <sdf@...ichev.me>, "haoluo@...gle.com" <haoluo@...gle.com>,
"jolsa@...nel.org" <jolsa@...nel.org>, "jgg@...pe.ca" <jgg@...pe.ca>,
"jhubbard@...dia.com" <jhubbard@...dia.com>, "peterx@...hat.com"
<peterx@...hat.com>, "jannh@...gle.com" <jannh@...gle.com>,
"pfalcato@...e.de" <pfalcato@...e.de>, "shuah@...nel.org" <shuah@...nel.org>,
"riel@...riel.com" <riel@...riel.com>, "ryan.roberts@....com"
<ryan.roberts@....com>, "jgross@...e.com" <jgross@...e.com>,
"yu-cheng.yu@...el.com" <yu-cheng.yu@...el.com>, "kas@...nel.org"
<kas@...nel.org>, "coxu@...hat.com" <coxu@...hat.com>,
"kevin.brodsky@....com" <kevin.brodsky@....com>, "ackerleytng@...gle.com"
<ackerleytng@...gle.com>, "maobibo@...ngson.cn" <maobibo@...ngson.cn>,
"prsampat@....com" <prsampat@....com>, "mlevitsk@...hat.com"
<mlevitsk@...hat.com>, "jmattson@...gle.com" <jmattson@...gle.com>,
"jthoughton@...gle.com" <jthoughton@...gle.com>, "agordeev@...ux.ibm.com"
<agordeev@...ux.ibm.com>, "alex@...ti.fr" <alex@...ti.fr>,
"aou@...s.berkeley.edu" <aou@...s.berkeley.edu>, "borntraeger@...ux.ibm.com"
<borntraeger@...ux.ibm.com>, "chenhuacai@...nel.org" <chenhuacai@...nel.org>,
"dev.jain@....com" <dev.jain@....com>, "gor@...ux.ibm.com"
<gor@...ux.ibm.com>, "hca@...ux.ibm.com" <hca@...ux.ibm.com>,
"palmer@...belt.com" <palmer@...belt.com>, "pjw@...nel.org" <pjw@...nel.org>,
"shijie@...amperecomputing.com" <shijie@...amperecomputing.com>,
"svens@...ux.ibm.com" <svens@...ux.ibm.com>, "thuth@...hat.com"
<thuth@...hat.com>, "wyihan@...gle.com" <wyihan@...gle.com>,
"yang@...amperecomputing.com" <yang@...amperecomputing.com>,
"Jonathan.Cameron@...wei.com" <Jonathan.Cameron@...wei.com>,
"Liam.Howlett@...cle.com" <Liam.Howlett@...cle.com>, "urezki@...il.com"
<urezki@...il.com>, "zhengqi.arch@...edance.com"
<zhengqi.arch@...edance.com>, "gerald.schaefer@...ux.ibm.com"
<gerald.schaefer@...ux.ibm.com>, "jiayuan.chen@...pee.com"
<jiayuan.chen@...pee.com>, "lenb@...nel.org" <lenb@...nel.org>,
"osalvador@...e.de" <osalvador@...e.de>, "pavel@...nel.org"
<pavel@...nel.org>, "rafael@...nel.org" <rafael@...nel.org>,
"vannapurve@...gle.com" <vannapurve@...gle.com>, "jackmanb@...gle.com"
<jackmanb@...gle.com>, "aneesh.kumar@...nel.org" <aneesh.kumar@...nel.org>,
"patrick.roy@...ux.dev" <patrick.roy@...ux.dev>, "Thomson, Jack"
<jackabt@...zon.co.uk>, "Itazuri, Takahiro" <itazur@...zon.co.uk>,
"Manwaring, Derek" <derekmn@...zon.com>, "Cali, Marco"
<xmarcalx@...zon.co.uk>, "Kalyazin, Nikita" <kalyazin@...zon.co.uk>
Subject: [PATCH v10 04/15] mm/gup: drop local variable in
gup_fast_folio_allowed
From: Nikita Kalyazin <kalyazin@...zon.com>
Move the check for pinning closer to where the result is used.
No functional changes.
Signed-off-by: Nikita Kalyazin <kalyazin@...zon.com>
---
mm/gup.c | 19 ++++++++-----------
1 file changed, 8 insertions(+), 11 deletions(-)
diff --git a/mm/gup.c b/mm/gup.c
index 9cad53acbc99..e72dacce3e34 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -2737,18 +2737,9 @@ EXPORT_SYMBOL(get_user_pages_unlocked);
*/
static bool gup_fast_folio_allowed(struct folio *folio, unsigned int flags)
{
- bool reject_file_backed = false;
struct address_space *mapping;
unsigned long mapping_flags;
- /*
- * If we aren't pinning then no problematic write can occur. A long term
- * pin is the most egregious case so this is the one we disallow.
- */
- if ((flags & (FOLL_PIN | FOLL_LONGTERM | FOLL_WRITE)) ==
- (FOLL_PIN | FOLL_LONGTERM | FOLL_WRITE))
- reject_file_backed = true;
-
/* We hold a folio reference, so we can safely access folio fields. */
if (WARN_ON_ONCE(folio_test_slab(folio)))
return false;
@@ -2793,8 +2784,14 @@ static bool gup_fast_folio_allowed(struct folio *folio, unsigned int flags)
*/
if (secretmem_mapping(mapping))
return false;
- /* The only remaining allowed file system is shmem. */
- return !reject_file_backed || shmem_mapping(mapping);
+
+ /*
+ * If we aren't pinning then no problematic write can occur. A long term
+ * pin is the most egregious case so this is the one we disallow.
+ * Also check the only remaining allowed file system - shmem.
+ */
+ return (flags & (FOLL_PIN | FOLL_LONGTERM | FOLL_WRITE)) !=
+ (FOLL_PIN | FOLL_LONGTERM | FOLL_WRITE) || shmem_mapping(mapping);
}
static void __maybe_unused gup_fast_undo_dev_pagemap(int *nr, int nr_start,
--
2.50.1
Powered by blists - more mailing lists