locking/static_keys: Fix up the static keys documentation

DEFINE_STATIC_KEY_TRUE(key);

DEFINE_STATIC_KEY_TRUE(key);

DEFINE_STATIC_KEY_FALSE(key);

DEFINE_STATIC_KEY_FALSE(key);

static_key_likely()

static_branch_likely()

static_key_unlikely()

static_branch_unlikely()

0) Abstract

0) Abstract

 *

 *

 * DEFINE_STATIC_KEY_TRUE(key);

 * DEFINE_STATIC_KEY_TRUE(key);

 * DEFINE_STATIC_KEY_FALSE(key);

 * DEFINE_STATIC_KEY_FALSE(key);

 * static_key_likely()

 * static_branch_likely()

 * static_key_unlikely()

 * static_branch_unlikely()

 *

 *

 * Jump labels provide an interface to generate dynamic branches using

 * Jump labels provide an interface to generate dynamic branches using

 * self-modifying code. Assuming toolchain and architecture support, if we

 * self-modifying code. Assuming toolchain and architecture support, if we

 * statement, setting the key to true requires us to patch in a jump

 * statement, setting the key to true requires us to patch in a jump

 * to the out-of-line of true branch.

 * to the out-of-line of true branch.

 *

 *

 * In addtion to static_branch_{enable,disable}, we can also reference count

 * In addition to static_branch_{enable,disable}, we can also reference count

 * the key or branch direction via static_branch_{inc,dec}. Thus,

 * the key or branch direction via static_branch_{inc,dec}. Thus,

 * static_branch_inc() can be thought of as a 'make more true' and

 * static_branch_inc() can be thought of as a 'make more true' and

 * static_branch_dec() as a 'make more false'. The inc()/dec()

 * static_branch_dec() as a 'make more false'.

 * interface is meant to be used exclusively from the inc()/dec() for a given

 * key.

 *

 *

 * Since this relies on modifying code, the branch modifying functions

 * Since this relies on modifying code, the branch modifying functions

 * must be considered absolute slow paths (machine wide synchronization etc.).

 * must be considered absolute slow paths (machine wide synchronization etc.).