kernfs: do not alloc iattrs in kernfs_xattr_get

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>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
[PM: minor merge fixes]
Signed-off-by: Paul Moore <paul@paul-moore.com>
This commit is contained in:
Ondrej Mosnacek 2019-02-22 15:57:13 +01:00 committed by Paul Moore
parent 0589521962
commit d0c9c153b4

View File

@ -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 = kmem_cache_zalloc(kernfs_iattrs_cache, GFP_KERNEL);
@ -60,6 +60,16 @@ static struct kernfs_iattrs *kernfs_iattrs(struct kernfs_node *kn)
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);
}