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Commit 7581fdf6 authored by NeilBrown's avatar NeilBrown Committed by Greg Kroah-Hartman
Browse files

cred: allow get_cred() and put_cred() to be given NULL. 



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: default avatarNeilBrown <neilb@suse.com>
Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 764ac04d

include/linux/cred.h

+9 −5
Original line number Diff line number Diff line
@@ -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
@@ -271,10 +273,12 @@ static inline void put_cred(const struct cred *_cred) 
{

	struct cred *cred = (struct cred *) _cred;



	if (cred) {

		validate_creds(cred);

		if (atomic_dec_and_test(&(cred)->usage))

			__put_cred(cred);

	}

}



/**

 * current_cred - Access the current task's subjective credentials