From d0c9c153b4bd6963c8fcccbc0caa12e8fa8d971d Mon Sep 17 00:00:00 2001 From: Ondrej Mosnacek Date: Fri, 22 Feb 2019 15:57:13 +0100 Subject: [PATCH] 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 Acked-by: Casey Schaufler [PM: minor merge fixes] Signed-off-by: Paul Moore --- 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 7d30b4949a84..5c5569fb2110 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 = 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); }