[PATCH v7 2/7] kernfs: do not alloc iattrs in kernfs_xattr_get
From: Ondrej Mosnacek <omosnace@redhat.com>
Date: 2019-02-22 14:57:54
Also in:
linux-fsdevel, selinux
Subsystem:
filesystems (vfs and infrastructure), kernfs, the rest · Maintainers:
Alexander Viro, Christian Brauner, Greg Kroah-Hartman, Tejun Heo, Linus Torvalds
This is a read-only operation, so we can simply return -ENODATA if kn->iattr is NULL. Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com> --- fs/kernfs/inode.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-)
diff --git a/fs/kernfs/inode.c b/fs/kernfs/inode.c
index ffd1ef962728..7a7985961bbf 100644
--- a/fs/kernfs/inode.c
+++ b/fs/kernfs/inode.c@@ -31,14 +31,14 @@ static const struct inode_operations kernfs_iops = { .listxattr = kernfs_iop_listxattr, }; -static struct kernfs_iattrs *kernfs_iattrs(struct kernfs_node *kn) +static struct kernfs_iattrs *__kernfs_iattrs(struct kernfs_node *kn, int alloc) { static DEFINE_MUTEX(iattr_mutex); struct kernfs_iattrs *ret; mutex_lock(&iattr_mutex); - if (kn->iattr) + if (kn->iattr || !alloc) goto out_unlock; kn->iattr = kzalloc(sizeof(struct kernfs_iattrs), GFP_KERNEL);
@@ -60,6 +60,16 @@ out_unlock: return ret; } +static struct kernfs_iattrs *kernfs_iattrs(struct kernfs_node *kn) +{ + return __kernfs_iattrs(kn, 1); +} + +static struct kernfs_iattrs *kernfs_iattrs_noalloc(struct kernfs_node *kn) +{ + return __kernfs_iattrs(kn, 0); +} + int __kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr) { struct kernfs_iattrs *attrs;
@@ -306,9 +316,9 @@ static int kernfs_xattr_get(const struct xattr_handler *handler, struct kernfs_node *kn = inode->i_private; struct kernfs_iattrs *attrs; - attrs = kernfs_iattrs(kn); + attrs = kernfs_iattrs_noalloc(kn); if (!attrs) - return -ENOMEM; + return -ENODATA; return simple_xattr_get(&attrs->xattrs, name, value, size); }
--
2.20.1