Commit 058cc23b authored by Mauro Carvalho Chehab's avatar Mauro Carvalho Chehab Committed by Paul E. McKenney

docs: RCU: Convert lockdep.txt to ReST

- Add a SPDX header;
- Adjust document title;
- Mark literal blocks as such;
- Add it to RCU/index.rst.
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
parent a3b0a79f
......@@ -11,6 +11,7 @@ RCU concepts
arrayRCU
checklist
lockdep
lockdep-splat
rcubarrier
rcu_dereference
......
.. SPDX-License-Identifier: GPL-2.0
========================
RCU and lockdep checking
========================
All flavors of RCU have lockdep checking available, so that lockdep is
aware of when each task enters and leaves any flavor of RCU read-side
......@@ -8,7 +12,7 @@ tracking to include RCU state, which can sometimes help when debugging
deadlocks and the like.
In addition, RCU provides the following primitives that check lockdep's
state:
state::
rcu_read_lock_held() for normal RCU.
rcu_read_lock_bh_held() for RCU-bh.
......@@ -63,7 +67,7 @@ checking of rcu_dereference() primitives:
The rcu_dereference_check() check expression can be any boolean
expression, but would normally include a lockdep expression. However,
any boolean expression can be used. For a moderately ornate example,
consider the following:
consider the following::
file = rcu_dereference_check(fdt->fd[fd],
lockdep_is_held(&files->file_lock) ||
......@@ -82,7 +86,7 @@ RCU read-side critical sections, in case (2) the ->file_lock prevents
any change from taking place, and finally, in case (3) the current task
is the only task accessing the file_struct, again preventing any change
from taking place. If the above statement was invoked only from updater
code, it could instead be written as follows:
code, it could instead be written as follows::
file = rcu_dereference_protected(fdt->fd[fd],
lockdep_is_held(&files->file_lock) ||
......@@ -105,7 +109,7 @@ false and they are called from outside any RCU read-side critical section.
For example, the workqueue for_each_pwq() macro is intended to be used
either within an RCU read-side critical section or with wq->mutex held.
It is thus implemented as follows:
It is thus implemented as follows::
#define for_each_pwq(pwq, wq)
list_for_each_entry_rcu((pwq), &(wq)->pwqs, pwqs_node,
......
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