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Commit 57d34a6c authored by Kees Cook's avatar Kees Cook Committed by Paul E. McKenney
Browse files

rcu: Update docs to include kfree_rcu() 



Mention kfree_rcu() in the call_rcu() section.  Additionally fix the
example code for list replacement that used the wrong structure element.

Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent 0f9574d8

Documentation/RCU/listRCU.txt

+1 −1
Original line number Diff line number Diff line
@@ -205,7 +205,7 @@ RCU ("read-copy update") its name. The RCU code is as follows: 
				audit_copy_rule(&ne->rule, &e->rule);

				ne->rule.action = newaction;

				ne->rule.file_count = newfield_count;

				list_replace_rcu(e, ne);

				list_replace_rcu(&e->list, &ne->list);

				call_rcu(&e->rcu, audit_free_rule);

				return 0;

			}

Documentation/RCU/whatisRCU.txt

+11 −2
Original line number Diff line number Diff line
@@ -499,6 +499,8 @@ The foo_reclaim() function might appear as follows: 
	{

		struct foo *fp = container_of(rp, struct foo, rcu);



		foo_cleanup(fp->a);



		kfree(fp);

	}
@@ -521,6 +523,12 @@ o Use call_rcu() -after- removing a data element from an 
	read-side critical sections that might be referencing that

	data item.



If the callback for call_rcu() is not doing anything more than calling

kfree() on the structure, you can use kfree_rcu() instead of call_rcu()

to avoid having to write your own callback:



	kfree_rcu(old_fp, rcu);



Again, see checklist.txt for additional rules governing the use of RCU.
@@ -773,8 +781,8 @@ a single atomic update, converting to RCU will require special care. 


Also, the presence of synchronize_rcu() means that the RCU version of

delete() can now block.  If this is a problem, there is a callback-based

mechanism that never blocks, namely call_rcu(), that can be used in

place of synchronize_rcu().

mechanism that never blocks, namely call_rcu() or kfree_rcu(), that can

be used in place of synchronize_rcu().





7.  FULL LIST OF RCU APIs
@@ -813,6 +821,7 @@ RCU: Critical sections Grace period Barrier 
	rcu_read_unlock		synchronize_rcu

	rcu_dereference		synchronize_rcu_expedited

				call_rcu

				kfree_rcu





bh:	Critical sections	Grace period		Barrier