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-rw-r--r--include/linux/cred.h26
1 files changed, 21 insertions, 5 deletions
diff --git a/include/linux/cred.h b/include/linux/cred.h
index 7eed6101c791..4907c9df86b3 100644
--- a/include/linux/cred.h
+++ b/include/linux/cred.h
@@ -169,6 +169,7 @@ extern int change_create_files_as(struct cred *, struct inode *);
extern int set_security_override(struct cred *, u32);
extern int set_security_override_from_ctx(struct cred *, const char *);
extern int set_create_files_as(struct cred *, struct inode *);
+extern int cred_fscmp(const struct cred *, const struct cred *);
extern void __init cred_init(void);
/*
@@ -236,7 +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
@@ -247,16 +248,29 @@ 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);
}
+static inline const struct cred *get_cred_rcu(const struct cred *cred)
+{
+ struct cred *nonconst_cred = (struct cred *) cred;
+ if (!cred)
+ return NULL;
+ if (!atomic_inc_not_zero(&nonconst_cred->usage))
+ return NULL;
+ validate_creds(cred);
+ return cred;
+}
+
/**
* put_cred - Release a reference to a set of credentials
* @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
@@ -266,9 +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);
+ }
}
/**