Commit 34a64b6b authored by Lai Jiangshan's avatar Lai Jiangshan Committed by Paul E. McKenney
Browse files

srcu: Update synchronize_srcu()'s comments 



The core of SRCU is changed, but synchronize_srcu()'s comments describe
the old algorithm.  This commit therefore updates them to match the
new algorithm.

Signed-off-by: default avatarLai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent 511a0868

kernel/srcu.c

+6 −4
Original line number Diff line number Diff line
@@ -450,10 +450,12 @@ static void __synchronize_srcu(struct srcu_struct *sp, int trycount) 
 * synchronize_srcu - wait for prior SRCU read-side critical-section completion

 * @sp: srcu_struct with which to synchronize.

 *

 * Flip the completed counter, and wait for the old count to drain to zero.

 * As with classic RCU, the updater must use some separate means of

 * synchronizing concurrent updates.  Can block; must be called from

 * process context.

 * Wait for the count to drain to zero of both indexes. To avoid the

 * possible starvation of synchronize_srcu(), it waits for the count of

 * the index=((->completed & 1) ^ 1) to drain to zero at first,

 * and then flip the completed and wait for the count of the other index.

 *

 * Can block; must be called from process context.

 *

 * Note that it is illegal to call synchronize_srcu() from the corresponding

 * SRCU read-side critical section; doing so will result in deadlock.