From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932995AbdKFX5K (ORCPT ); Mon, 6 Nov 2017 18:57:10 -0500 Received: from aserp1040.oracle.com ([141.146.126.69]:18010 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932549AbdKFX5G (ORCPT ); Mon, 6 Nov 2017 18:57:06 -0500 Subject: Re: [PATCH v2 5/9] shmem: add sealing support to hugetlb-backed memfd To: =?UTF-8?Q?Marc-Andr=c3=a9_Lureau?= , linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: aarcange@redhat.com, hughd@google.com, nyc@holomorphy.com References: <20171106143944.13821-1-marcandre.lureau@redhat.com> <20171106143944.13821-6-marcandre.lureau@redhat.com> From: Mike Kravetz Message-ID: <11ac4287-18a0-6b10-79a2-7521a64e1738@oracle.com> Date: Mon, 6 Nov 2017 15:56:48 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 MIME-Version: 1.0 In-Reply-To: <20171106143944.13821-6-marcandre.lureau@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-Source-IP: userv0021.oracle.com [156.151.31.71] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/06/2017 06:39 AM, Marc-André Lureau wrote: > 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-André Lureau Looks fine to me, Reviewed-by: Mike Kravetz -- Mike Kravetz > --- > mm/shmem.c | 47 ++++++++++++++++++++++++++++------------------- > 1 file changed, 28 insertions(+), 19 deletions(-) > > diff --git a/mm/shmem.c b/mm/shmem.c > index b7811979611f..b08ba5d84d84 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_file_seals_ptr(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_file_seals_ptr(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: > @@ -2794,10 +2811,9 @@ static int memfd_add_seals(struct file *file, unsigned int seals) > > static int memfd_get_seals(struct file *file) > { > - if (file->f_op != &shmem_file_operations) > - return -EINVAL; > + unsigned int *seals = memfd_file_seals_ptr(file); > > - return SHMEM_I(file_inode(file))->seals; > + return seals ? *seals : -EINVAL; > } > > long memfd_fcntl(struct file *file, unsigned int cmd, unsigned long arg) > @@ -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_file_seals_ptr(file); > + *file_seals &= ~F_SEAL_SEAL; > } > > fd_install(fd, file); >