Hi ----- Original Message ----- > On 10/31/2017 11:40 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 <marcandre.lureau@xxxxxxxxxx> > > --- > > 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) > > I would have named this something like 'memfd_file_seal_ptr', and not > changed the name of memfd_get_seals below. Just my preference, and it > does not carry as much weight as Hugh who originally write this code. > agreed and changed, thanks > > +{ > > + 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; > > +} > > + > > As mentioned in patch 2, I think this code will need to be restructured > so that hugetlbfs file sealing will work even is CONFIG_TMPFS is not > defined. The above routine is behind #ifdef CONFIG_TMPFS. > > In general the code looks fine, but this config issue needs to be addressed. See discussion in patch 2 > -- > Mike Kravetz > > > #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); > > > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@xxxxxxxxx. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: <a href=mailto:"dont@xxxxxxxxx"> email@xxxxxxxxx </a> > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href