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authorPaul E. McKenney <paulmck@kernel.org>2020-11-13 12:54:48 -0800
committerPaul E. McKenney <paulmck@kernel.org>2021-01-04 13:53:38 -0800
commit8b5bd67cf6422b63ee100d76d8de8960ca2df7f0 (patch)
tree9bc4242c2aa4cfaad727526339abf4ede5d15eb0 /include/linux/srcutiny.h
parent29d2bb94a8a126ce80ffbb433b648b32fdea524e (diff)
srcu: Provide polling interfaces for Tiny SRCU grace periods
There is a need for a polling interface for SRCU grace periods, so this commit supplies get_state_synchronize_srcu(), start_poll_synchronize_srcu(), and poll_state_synchronize_srcu() for this purpose. The first can be used if future grace periods are inevitable (perhaps due to a later call_srcu() invocation), the second if future grace periods might not otherwise happen, and the third to check if a grace period has elapsed since the corresponding call to either of the first two. As with get_state_synchronize_rcu() and cond_synchronize_rcu(), the return value from either get_state_synchronize_srcu() or start_poll_synchronize_srcu() must be passed in to a later call to poll_state_synchronize_srcu(). Link: https://lore.kernel.org/rcu/20201112201547.GF3365678@moria.home.lan/ Reported-by: Kent Overstreet <kent.overstreet@gmail.com> [ paulmck: Add EXPORT_SYMBOL_GPL() per kernel test robot feedback. ] [ paulmck: Apply feedback from Neeraj Upadhyay. ] Link: https://lore.kernel.org/lkml/20201117004017.GA7444@paulmck-ThinkPad-P72/ Reviewed-by: Neeraj Upadhyay <neeraju@codeaurora.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'include/linux/srcutiny.h')
-rw-r--r--include/linux/srcutiny.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/srcutiny.h b/include/linux/srcutiny.h
index b8b42d0a24f1..0e0cf4d6a72a 100644
--- a/include/linux/srcutiny.h
+++ b/include/linux/srcutiny.h
@@ -16,6 +16,7 @@
struct srcu_struct {
short srcu_lock_nesting[2]; /* srcu_read_lock() nesting depth. */
unsigned short srcu_idx; /* Current reader array element in bit 0x2. */
+ unsigned short srcu_idx_max; /* Furthest future srcu_idx request. */
u8 srcu_gp_running; /* GP workqueue running? */
u8 srcu_gp_waiting; /* GP waiting for readers? */
struct swait_queue_head srcu_wq;