| 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: <20250625231838.1897085-26-pasha.tatashin@soleen.com>
Date: Wed, 25 Jun 2025 23:18:12 +0000
From: Pasha Tatashin <pasha.tatashin@...een.com>
To: pratyush@...nel.org,
jasonmiu@...gle.com,
graf@...zon.com,
changyuanl@...gle.com,
pasha.tatashin@...een.com,
rppt@...nel.org,
dmatlack@...gle.com,
rientjes@...gle.com,
corbet@....net,
rdunlap@...radead.org,
ilpo.jarvinen@...ux.intel.com,
kanie@...ux.alibaba.com,
ojeda@...nel.org,
aliceryhl@...gle.com,
masahiroy@...nel.org,
akpm@...ux-foundation.org,
tj@...nel.org,
yoann.congal@...le.fr,
mmaurer@...gle.com,
roman.gushchin@...ux.dev,
chenridong@...wei.com,
axboe@...nel.dk,
mark.rutland@....com,
jannh@...gle.com,
vincent.guittot@...aro.org,
hannes@...xchg.org,
dan.j.williams@...el.com,
david@...hat.com,
joel.granados@...nel.org,
rostedt@...dmis.org,
anna.schumaker@...cle.com,
song@...nel.org,
zhangguopeng@...inos.cn,
linux@...ssschuh.net,
linux-kernel@...r.kernel.org,
linux-doc@...r.kernel.org,
linux-mm@...ck.org,
gregkh@...uxfoundation.org,
tglx@...utronix.de,
mingo@...hat.com,
bp@...en8.de,
dave.hansen@...ux.intel.com,
x86@...nel.org,
hpa@...or.com,
rafael@...nel.org,
dakr@...nel.org,
bartosz.golaszewski@...aro.org,
cw00.choi@...sung.com,
myungjoo.ham@...sung.com,
yesanishhere@...il.com,
Jonathan.Cameron@...wei.com,
quic_zijuhu@...cinc.com,
aleksander.lobakin@...el.com,
ira.weiny@...el.com,
andriy.shevchenko@...ux.intel.com,
leon@...nel.org,
lukas@...ner.de,
bhelgaas@...gle.com,
wagi@...nel.org,
djeffery@...hat.com,
stuart.w.hayes@...il.com,
ptyadav@...zon.de,
lennart@...ttering.net,
brauner@...nel.org,
linux-api@...r.kernel.org,
linux-fsdevel@...r.kernel.org
Subject: [PATCH v1 25/32] mm: shmem: use SHMEM_F_* flags instead of VM_* flags
From: Pratyush Yadav <ptyadav@...zon.de>
shmem_inode_info::flags can have the VM flags VM_NORESERVE and
VM_LOCKED. These are used to suppress pre-accounting or to lock the
pages in the inode respectively. Using the VM flags directly makes it
difficult to add shmem-specific flags that are unrelated to VM behavior
since one would need to find a VM flag not used by shmem and re-purpose
it.
Introduce SHMEM_F_NORESERVE and SHMEM_F_LOCKED which represent the same
information, but their bits are independent of the VM flags. Callers can
still pass VM_NORESERVE to shmem_get_inode(), but it gets transformed to
the shmem-specific flag internally.
No functional changes intended.
Signed-off-by: Pratyush Yadav <ptyadav@...zon.de>
Signed-off-by: Pasha Tatashin <pasha.tatashin@...een.com>
---
include/linux/shmem_fs.h | 6 ++++++
mm/shmem.c | 24 +++++++++++++-----------
2 files changed, 19 insertions(+), 11 deletions(-)
diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h
index 5f03a39a26f7..578a5f3d1935 100644
--- a/include/linux/shmem_fs.h
+++ b/include/linux/shmem_fs.h
@@ -10,6 +10,7 @@
#include <linux/xattr.h>
#include <linux/fs_parser.h>
#include <linux/userfaultfd_k.h>
+#include <linux/bits.h>
/* inode in-kernel data */
@@ -17,6 +18,11 @@
#define SHMEM_MAXQUOTAS 2
#endif
+/* Suppress pre-accounting of the entire object size. */
+#define SHMEM_F_NORESERVE BIT(0)
+/* Disallow swapping. */
+#define SHMEM_F_LOCKED BIT(1)
+
struct shmem_inode_info {
spinlock_t lock;
unsigned int seals; /* shmem seals */
diff --git a/mm/shmem.c b/mm/shmem.c
index 3a5a65b1f41a..953d89f62882 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -175,20 +175,20 @@ static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb)
*/
static inline int shmem_acct_size(unsigned long flags, loff_t size)
{
- return (flags & VM_NORESERVE) ?
+ return (flags & SHMEM_F_NORESERVE) ?
0 : security_vm_enough_memory_mm(current->mm, VM_ACCT(size));
}
static inline void shmem_unacct_size(unsigned long flags, loff_t size)
{
- if (!(flags & VM_NORESERVE))
+ if (!(flags & SHMEM_F_NORESERVE))
vm_unacct_memory(VM_ACCT(size));
}
static inline int shmem_reacct_size(unsigned long flags,
loff_t oldsize, loff_t newsize)
{
- if (!(flags & VM_NORESERVE)) {
+ if (!(flags & SHMEM_F_NORESERVE)) {
if (VM_ACCT(newsize) > VM_ACCT(oldsize))
return security_vm_enough_memory_mm(current->mm,
VM_ACCT(newsize) - VM_ACCT(oldsize));
@@ -206,7 +206,7 @@ static inline int shmem_reacct_size(unsigned long flags,
*/
static inline int shmem_acct_blocks(unsigned long flags, long pages)
{
- if (!(flags & VM_NORESERVE))
+ if (!(flags & SHMEM_F_NORESERVE))
return 0;
return security_vm_enough_memory_mm(current->mm,
@@ -215,7 +215,7 @@ static inline int shmem_acct_blocks(unsigned long flags, long pages)
static inline void shmem_unacct_blocks(unsigned long flags, long pages)
{
- if (flags & VM_NORESERVE)
+ if (flags & SHMEM_F_NORESERVE)
vm_unacct_memory(pages * VM_ACCT(PAGE_SIZE));
}
@@ -1557,7 +1557,7 @@ int shmem_writeout(struct folio *folio, struct writeback_control *wbc)
if (WARN_ON_ONCE(!wbc->for_reclaim))
goto redirty;
- if ((info->flags & VM_LOCKED) || sbinfo->noswap)
+ if ((info->flags & SHMEM_F_LOCKED) || sbinfo->noswap)
goto redirty;
if (!total_swap_pages)
@@ -2910,15 +2910,15 @@ int shmem_lock(struct file *file, int lock, struct ucounts *ucounts)
* ipc_lock_object() when called from shmctl_do_lock(),
* no serialization needed when called from shm_destroy().
*/
- if (lock && !(info->flags & VM_LOCKED)) {
+ if (lock && !(info->flags & SHMEM_F_LOCKED)) {
if (!user_shm_lock(inode->i_size, ucounts))
goto out_nomem;
- info->flags |= VM_LOCKED;
+ info->flags |= SHMEM_F_LOCKED;
mapping_set_unevictable(file->f_mapping);
}
- if (!lock && (info->flags & VM_LOCKED) && ucounts) {
+ if (!lock && (info->flags & SHMEM_F_LOCKED) && ucounts) {
user_shm_unlock(inode->i_size, ucounts);
- info->flags &= ~VM_LOCKED;
+ info->flags &= ~SHMEM_F_LOCKED;
mapping_clear_unevictable(file->f_mapping);
}
retval = 0;
@@ -3062,7 +3062,9 @@ static struct inode *__shmem_get_inode(struct mnt_idmap *idmap,
spin_lock_init(&info->lock);
atomic_set(&info->stop_eviction, 0);
info->seals = F_SEAL_SEAL;
- info->flags = flags & VM_NORESERVE;
+ info->flags = 0;
+ if (flags & VM_NORESERVE)
+ info->flags |= SHMEM_F_NORESERVE;
info->i_crtime = inode_get_mtime(inode);
info->fsflags = (dir == NULL) ? 0 :
SHMEM_I(dir)->fsflags & SHMEM_FL_INHERITED;
--
2.50.0.727.gbf7dc18ff4-goog
Powered by blists - more mailing lists