@@ -237,7 +237,7 @@ static inline struct cred *get_new_cred(struct cred *cred)
* @cred: The credentials to reference
*
* Get a reference on the specified set of credentials. The caller must
- * release the reference.
+ * release the reference. If %NULL is passed, it is returned with no action.
*
* This is used to deal with a committed set of credentials. Although the
* pointer is const, this will temporarily discard the const and increment the
@@ -248,6 +248,8 @@ static inline struct cred *get_new_cred(struct cred *cred)
static inline const struct cred *get_cred(const struct cred *cred)
{
struct cred *nonconst_cred = (struct cred *) cred;
+ if (!cred)
+ return cred;
validate_creds(cred);
return get_new_cred(nonconst_cred);
}
@@ -268,7 +270,7 @@ static inline const struct cred *get_cred_rcu(const struct cred *cred)
* @cred: The credentials to release
*
* Release a reference to a set of credentials, deleting them when the last ref
- * is released.
+ * is released. If %NULL is passed, nothing is done.
*
* This takes a const pointer to a set of credentials because the credentials
* on task_struct are attached by const pointers to prevent accidental
@@ -278,9 +280,11 @@ static inline void put_cred(const struct cred *_cred)
{
struct cred *cred = (struct cred *) _cred;
- validate_creds(cred);
- if (atomic_dec_and_test(&(cred)->usage))
- __put_cred(cred);
+ if (cred) {
+ validate_creds(cred);
+ if (atomic_dec_and_test(&(cred)->usage))
+ __put_cred(cred);
+ }
}
/**
It is common practice for helpers like this to silently, accept a NULL pointer. get_rpccred() and put_rpccred() used by NFS act this way and using the same interface will ease the conversion for NFS, and simplify the resulting code. Signed-off-by: NeilBrown <neilb@suse.com> --- include/linux/cred.h | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-)