From: NeilBrown neilb@suse.com
stable inclusion from linux-4.19.209 commit 7581fdf6c01991f03b1b51d524f1b7b64c920ce3
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commit f06bc03339ad4c1baa964a5f0606247ac1c3c50b upstream.
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 Signed-off-by: Anna Schumaker Anna.Schumaker@Netapp.com Cc: Eric Dumazet edumazet@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Acked-by: Jason Yan yanaijie@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- include/linux/cred.h | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/include/linux/cred.h b/include/linux/cred.h index 1dc351d8548bf..4b081e4911c84 100644 --- a/include/linux/cred.h +++ b/include/linux/cred.h @@ -240,7 +240,7 @@ 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 @@ -251,6 +251,8 @@ 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); nonconst_cred->non_rcu = 0; return get_new_cred(nonconst_cred); @@ -261,7 +263,7 @@ static inline const struct cred *get_cred(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 @@ -271,9 +273,11 @@ 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); + } }
/**