From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-f72.google.com (mail-oi0-f72.google.com [209.85.218.72]) by kanga.kvack.org (Postfix) with ESMTP id D90BD6B026D for ; Tue, 31 Oct 2017 14:41:18 -0400 (EDT) Received: by mail-oi0-f72.google.com with SMTP id q4so19772461oic.12 for ; Tue, 31 Oct 2017 11:41:18 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id 32si1301809otg.512.2017.10.31.11.41.17 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 31 Oct 2017 11:41:17 -0700 (PDT) From: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= Subject: [PATCH 5/6] shmem: add sealing support to hugetlb-backed memfd Date: Tue, 31 Oct 2017 19:40:51 +0100 Message-Id: <20171031184052.25253-6-marcandre.lureau@redhat.com> In-Reply-To: <20171031184052.25253-1-marcandre.lureau@redhat.com> References: <20171031184052.25253-1-marcandre.lureau@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org List-ID: To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: aarcange@redhat.com, hughd@google.com, nyc@holomorphy.com, mike.kravetz@oracle.com, =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= Adapt add_seals()/get_seals() to work with hugetbfs-backed memory. Teach memfd_create() to allow sealing operations on MFD_HUGETLB. Signed-off-by: Marc-AndrA(C) Lureau --- mm/shmem.c | 51 ++++++++++++++++++++++++++++++--------------------- 1 file changed, 30 insertions(+), 21 deletions(-) diff --git a/mm/shmem.c b/mm/shmem.c index b7811979611f..b7c59d993c19 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2717,6 +2717,19 @@ static int shmem_wait_for_pins(struct address_space *mapping) return error; } +static unsigned int *memfd_get_seals(struct file *file) +{ + if (file->f_op == &shmem_file_operations) + return &SHMEM_I(file_inode(file))->seals; + +#ifdef CONFIG_HUGETLBFS + if (file->f_op == &hugetlbfs_file_operations) + return &HUGETLBFS_I(file_inode(file))->seals; +#endif + + return NULL; +} + #define F_ALL_SEALS (F_SEAL_SEAL | \ F_SEAL_SHRINK | \ F_SEAL_GROW | \ @@ -2725,7 +2738,7 @@ static int shmem_wait_for_pins(struct address_space *mapping) static int memfd_add_seals(struct file *file, unsigned int seals) { struct inode *inode = file_inode(file); - struct shmem_inode_info *info = SHMEM_I(inode); + unsigned int *file_seals; int error; /* @@ -2758,8 +2771,6 @@ static int memfd_add_seals(struct file *file, unsigned int seals) * other file types. */ - if (file->f_op != &shmem_file_operations) - return -EINVAL; if (!(file->f_mode & FMODE_WRITE)) return -EPERM; if (seals & ~(unsigned int)F_ALL_SEALS) @@ -2767,12 +2778,18 @@ static int memfd_add_seals(struct file *file, unsigned int seals) inode_lock(inode); - if (info->seals & F_SEAL_SEAL) { + file_seals = memfd_get_seals(file); + if (!file_seals) { + error = -EINVAL; + goto unlock; + } + + if (*file_seals & F_SEAL_SEAL) { error = -EPERM; goto unlock; } - if ((seals & F_SEAL_WRITE) && !(info->seals & F_SEAL_WRITE)) { + if ((seals & F_SEAL_WRITE) && !(*file_seals & F_SEAL_WRITE)) { error = mapping_deny_writable(file->f_mapping); if (error) goto unlock; @@ -2784,7 +2801,7 @@ static int memfd_add_seals(struct file *file, unsigned int seals) } } - info->seals |= seals; + *file_seals |= seals; error = 0; unlock: @@ -2792,12 +2809,11 @@ static int memfd_add_seals(struct file *file, unsigned int seals) return error; } -static int memfd_get_seals(struct file *file) +static int memfd_fcntl_get_seals(struct file *file) { - if (file->f_op != &shmem_file_operations) - return -EINVAL; + unsigned int *seals = memfd_get_seals(file); - return SHMEM_I(file_inode(file))->seals; + return seals ? *seals : -EINVAL; } long memfd_fcntl(struct file *file, unsigned int cmd, unsigned long arg) @@ -2813,7 +2829,7 @@ long memfd_fcntl(struct file *file, unsigned int cmd, unsigned long arg) error = memfd_add_seals(file, arg); break; case F_GET_SEALS: - error = memfd_get_seals(file); + error = memfd_fcntl_get_seals(file); break; default: error = -EINVAL; @@ -3657,7 +3673,7 @@ SYSCALL_DEFINE2(memfd_create, const char __user *, uname, unsigned int, flags) { - struct shmem_inode_info *info; + unsigned int *file_seals; struct file *file; int fd, error; char *name; @@ -3667,9 +3683,6 @@ SYSCALL_DEFINE2(memfd_create, if (flags & ~(unsigned int)MFD_ALL_FLAGS) return -EINVAL; } else { - /* Sealing not supported in hugetlbfs (MFD_HUGETLB) */ - if (flags & MFD_ALLOW_SEALING) - return -EINVAL; /* Allow huge page size encoding in flags. */ if (flags & ~(unsigned int)(MFD_ALL_FLAGS | (MFD_HUGE_MASK << MFD_HUGE_SHIFT))) @@ -3722,12 +3735,8 @@ SYSCALL_DEFINE2(memfd_create, file->f_flags |= O_RDWR | O_LARGEFILE; if (flags & MFD_ALLOW_SEALING) { - /* - * flags check at beginning of function ensures - * this is not a hugetlbfs (MFD_HUGETLB) file. - */ - info = SHMEM_I(file_inode(file)); - info->seals &= ~F_SEAL_SEAL; + file_seals = memfd_get_seals(file); + *file_seals &= ~F_SEAL_SEAL; } fd_install(fd, file); -- 2.15.0.rc0.40.gaefcc5f6f -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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