find_or_insert_direct_key

Name:Find/insert the given key into the fscrypt_direct_keys table. If found, it* is returned with elevated refcount, and 'to_insert' is freed if non-NULL. If* not found, 'to_insert' is inserted and returned if it's non-NULL; otherwise* NULL is returned.

Proto:static struct fscrypt_direct_key *find_or_insert_direct_key(struct fscrypt_direct_key *to_insert, const u8 *raw_key, const struct fscrypt_info *ci)

Type:struct fscrypt_direct_key

Parameter:

Type	Parameter	Name
struct fscrypt_direct_key *	to_insert
const u8 *	raw_key
const struct fscrypt_info *	ci

191

BUILD_BUG_ON - break compile if a condition is true( size of hash_key > FSCRYPT_KEY_DESCRIPTOR_SIZE)

192

memcpy( & hash_key, master_key_descriptor, size of hash_key )

195

spin_lock( & fscrypt_direct_keys_lock)

196

hash_for_each_possible - iterate over all possible objects hashing to the* same bucket*@name: hashtable to iterate*@obj: the type * to use as a loop cursor for each entry*@member: the name of the hlist_node within the struct*@key: the key of the objects (Table of keys referenced by DIRECT_KEY policies , dk, dk_node, hash_key)

197

If memcmp(master_key_descriptor, dk_descriptor, FSCRYPT_KEY_DESCRIPTOR_SIZE) != 0 Then Continue

200

If Encryption mode used for this inode. It corresponds to either the* contents or filenames encryption mode, depending on the inode type. != dk_mode Then Continue

202

If rypto_memneq - Compare two areas of memory without leaking* timing information.*@a: One area of memory*@b: Another area of memory*@size: The size of the area.* Returns 0 when data is equal, 1 otherwise. Then Continue

205

_inc - increment a refcount*@r: the refcount to increment* Similar to atomic_inc(), but will saturate at REFCOUNT_SATURATED and WARN

206

spin_unlock( & fscrypt_direct_keys_lock)

207

free_direct_key(to_insert)

208

Return dk

210

If to_insert Then hash_add - add an object to a hashtable*@hashtable: hashtable to add to*@node: the &struct hlist_node of the object to be added*@key: the key of the object to be added(Table of keys referenced by DIRECT_KEY policies , & dk_node, hash_key)

212

spin_unlock( & fscrypt_direct_keys_lock)

213

Return to_insert

**Caller**
Name	Describe
fscrypt_get_direct_key	Prepare to encrypt directly using the master key in the given mode

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