From: Hugh Dickins <hughd@google.com> To: Andrew Morton <akpm@linux-foundation.org> Cc: Hugh Dickins <hughd@google.com>, Shakeel Butt <shakeelb@google.com>, "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>, Yang Shi <shy828301@gmail.com>, Miaohe Lin <linmiaohe@huawei.com>, Mike Kravetz <mike.kravetz@oracle.com>, Michal Hocko <mhocko@suse.com>, Rik van Riel <riel@surriel.com>, Christoph Hellwig <hch@infradead.org>, Matthew Wilcox <willy@infradead.org>, "Eric W. Biederman" <ebiederm@xmission.com>, Alexey Gladkov <legion@kernel.org>, Chris Wilson <chris@chris-wilson.co.uk>, Matthew Auld <matthew.auld@intel.com>, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH 16/16] memfd: memfd_create(name, MFD_MEM_LOCK) for memlocked shmem Date: Fri, 30 Jul 2021 01:13:00 -0700 (PDT) [thread overview] Message-ID: <be7c30cc-20fd-b5d6-83a2-366410753145@google.com> (raw) In-Reply-To: <2862852d-badd-7486-3a8e-c5ea9666d6fb@google.com> Now that the size of a memlocked file can be changed, memfd_create() can accept an MFD_MEM_LOCK flag to request memlocking, even though the initial size is of course 0. Signed-off-by: Hugh Dickins <hughd@google.com> --- include/uapi/linux/memfd.h | 1 + mm/memfd.c | 7 +++++-- mm/shmem.c | 13 ++++++++++++- 3 files changed, 18 insertions(+), 3 deletions(-) diff --git a/include/uapi/linux/memfd.h b/include/uapi/linux/memfd.h index 8358a69e78cc..9113b5aa1763 100644 --- a/include/uapi/linux/memfd.h +++ b/include/uapi/linux/memfd.h @@ -9,6 +9,7 @@ #define MFD_ALLOW_SEALING 0x0002U #define MFD_HUGETLB 0x0004U /* Use hugetlbfs */ #define MFD_HUGEPAGE 0x0008U /* Use huge tmpfs */ +#define MFD_MEM_LOCK 0x0010U /* Memlock tmpfs */ /* * Huge page size encoding when MFD_HUGETLB is specified, and a huge page diff --git a/mm/memfd.c b/mm/memfd.c index 0d1a504d2fc9..e39f9eed55d2 100644 --- a/mm/memfd.c +++ b/mm/memfd.c @@ -248,7 +248,8 @@ long memfd_fcntl(struct file *file, unsigned int cmd, unsigned long arg) #define MFD_ALL_FLAGS (MFD_CLOEXEC | \ MFD_ALLOW_SEALING | \ MFD_HUGETLB | \ - MFD_HUGEPAGE) + MFD_HUGEPAGE | \ + MFD_MEM_LOCK) SYSCALL_DEFINE2(memfd_create, const char __user *, uname, @@ -262,7 +263,7 @@ SYSCALL_DEFINE2(memfd_create, if (flags & MFD_HUGETLB) { /* Disallow huge tmpfs when choosing hugetlbfs */ - if (flags & MFD_HUGEPAGE) + if (flags & (MFD_HUGEPAGE | MFD_MEM_LOCK)) return -EINVAL; /* Allow huge page size encoding in flags. */ if (flags & ~(unsigned int)(MFD_ALL_FLAGS | @@ -314,6 +315,8 @@ SYSCALL_DEFINE2(memfd_create, if (flags & MFD_HUGEPAGE) vm_flags |= VM_HUGEPAGE; + if (flags & MFD_MEM_LOCK) + vm_flags |= VM_LOCKED; file = shmem_file_setup(name, 0, vm_flags); } diff --git a/mm/shmem.c b/mm/shmem.c index fa4a264453bf..a0a83e59ae07 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2395,7 +2395,7 @@ static struct inode *shmem_get_inode(struct super_block *sb, const struct inode spin_lock_init(&info->lock); atomic_set(&info->stop_eviction, 0); info->seals = F_SEAL_SEAL; - info->flags = flags & VM_NORESERVE; + info->flags = flags & (VM_NORESERVE | VM_LOCKED); if ((flags & VM_HUGEPAGE) && transparent_hugepage_allowed(sbinfo) && !test_bit(MMF_DISABLE_THP, ¤t->mm->flags)) @@ -4254,6 +4254,17 @@ static struct file *__shmem_file_setup(struct vfsmount *mnt, const char *name, l inode->i_size = size; clear_nlink(inode); /* It is unlinked */ res = ERR_PTR(ramfs_nommu_expand_for_mapping(inode, size)); + if (!IS_ERR(res) && (flags & VM_LOCKED)) { + struct ucounts *ucounts = current_ucounts(); + /* + * Only memfd_create() may pass VM_LOCKED, and it passes + * size 0; but avoid that assumption in case it changes. + */ + if (user_shm_lock(size, ucounts, true)) + SHMEM_I(inode)->mlock_ucounts = ucounts; + else + res = ERR_PTR(-EPERM); + } if (!IS_ERR(res)) res = alloc_file_pseudo(inode, mnt, name, O_RDWR, &shmem_file_operations); -- 2.26.2
prev parent reply other threads:[~2021-07-30 8:13 UTC|newest] Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-07-30 7:22 [PATCH 00/16] tmpfs: HUGEPAGE and MEM_LOCK fcntls and memfds Hugh Dickins 2021-07-30 7:25 ` [PATCH 01/16] huge tmpfs: fix fallocate(vanilla) advance over huge pages Hugh Dickins 2021-07-30 21:36 ` Yang Shi 2021-08-01 3:38 ` Hugh Dickins 2021-08-02 20:36 ` Yang Shi 2021-07-30 7:28 ` [PATCH 02/16] huge tmpfs: fix split_huge_page() after FALLOC_FL_KEEP_SIZE Hugh Dickins 2021-07-30 23:48 ` Yang Shi 2021-07-30 7:30 ` [PATCH 03/16] huge tmpfs: remove shrinklist addition from shmem_setattr() Hugh Dickins 2021-07-30 21:50 ` Yang Shi 2021-07-30 7:36 ` [PATCH 04/16] huge tmpfs: revert shmem's use of transhuge_vma_enabled() Hugh Dickins 2021-07-30 21:56 ` Yang Shi 2021-08-01 4:01 ` Hugh Dickins 2021-08-02 20:39 ` Yang Shi 2021-07-30 7:39 ` [PATCH 05/16] huge tmpfs: move shmem_huge_enabled() upwards Hugh Dickins 2021-07-30 21:57 ` Yang Shi 2021-07-30 7:42 ` [PATCH 06/16] huge tmpfs: shmem_is_huge(vma, inode, index) Hugh Dickins 2021-07-30 23:34 ` Yang Shi 2021-08-01 5:22 ` Hugh Dickins 2021-08-01 5:37 ` Hugh Dickins 2021-08-02 21:14 ` Yang Shi 2021-08-04 8:28 ` Hugh Dickins 2021-08-04 19:01 ` Yang Shi 2021-08-06 5:21 ` Hugh Dickins 2021-08-06 17:41 ` Yang Shi 2021-08-05 23:04 ` Yang Shi 2021-08-06 5:43 ` Hugh Dickins 2021-08-06 17:57 ` Yang Shi 2021-08-12 18:19 ` Yang Shi 2021-07-30 7:45 ` [PATCH 07/16] memfd: memfd_create(name, MFD_HUGEPAGE) for shmem huge pages Hugh Dickins 2021-08-04 14:03 ` Kirill A. Shutemov 2021-08-06 3:33 ` Hugh Dickins 2021-07-30 7:48 ` [PATCH 08/16] huge tmpfs: fcntl(fd, F_HUGEPAGE) and fcntl(fd, F_NOHUGEPAGE) Hugh Dickins 2021-08-04 14:08 ` Kirill A. Shutemov 2021-08-06 4:34 ` Hugh Dickins 2021-07-30 7:51 ` [PATCH 09/16] huge tmpfs: decide stat.st_blksize by shmem_is_huge() Hugh Dickins 2021-07-30 23:40 ` Yang Shi 2021-07-30 7:55 ` [PATCH 10/16] tmpfs: fcntl(fd, F_MEM_LOCK) to memlock a tmpfs file Hugh Dickins 2021-08-03 1:38 ` Matthew Wilcox 2021-08-04 9:15 ` Hugh Dickins 2021-07-30 7:57 ` [PATCH 11/16] tmpfs: fcntl(fd, F_MEM_LOCKED) to test if memlocked Hugh Dickins 2021-07-30 8:00 ` [PATCH 12/16] tmpfs: refuse memlock when fallocated beyond i_size Hugh Dickins 2021-07-30 8:03 ` [PATCH 13/16] mm: bool user_shm_lock(loff_t size, struct ucounts *) Hugh Dickins 2021-07-30 8:06 ` [PATCH 14/16] mm: user_shm_lock(,,getuc) and user_shm_unlock(,,putuc) Hugh Dickins 2021-07-30 8:09 ` [PATCH 15/16] tmpfs: permit changing size of memlocked file Hugh Dickins 2021-07-30 8:13 ` Hugh Dickins [this message]
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