This commit renames the srcu_check_read_flavor_lite() function to
srcu_check_read_flavor_force() and adds a read_flavor argument in order to
support an srcu_read_lock_fast() variant that is to avoid array indexing
in both the lock and unlock primitives.
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
Cc: Andrii Nakryiko <andrii@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Kent Overstreet <kent.overstreet@xxxxxxxxx>
Cc: <bpf@xxxxxxxxxxxxxxx>
---
include/linux/srcu.h | 2 +-
include/linux/srcutiny.h | 2 +-
include/linux/srcutree.h | 10 ++++++----
3 files changed, 8 insertions(+), 6 deletions(-)
diff --git a/include/linux/srcu.h b/include/linux/srcu.h
index f6f779b9d9ff2..ca00b9af7c237 100644
--- a/include/linux/srcu.h
+++ b/include/linux/srcu.h
@@ -279,7 +279,7 @@ static inline int srcu_read_lock_lite(struct srcu_struct *ssp) __acquires(ssp)
{
int retval;
- srcu_check_read_flavor_lite(ssp);
+ srcu_check_read_flavor_force(ssp, SRCU_READ_FLAVOR_LITE);
retval = __srcu_read_lock_lite(ssp);
rcu_try_lock_acquire(&ssp->dep_map);
return retval;
diff --git a/include/linux/srcutiny.h b/include/linux/srcutiny.h
index 31b59b4be2a74..6b1a7276aa4c9 100644
--- a/include/linux/srcutiny.h
+++ b/include/linux/srcutiny.h
@@ -82,7 +82,7 @@ static inline void srcu_barrier(struct srcu_struct *ssp)
}
#define srcu_check_read_flavor(ssp, read_flavor) do { } while (0)
-#define srcu_check_read_flavor_lite(ssp) do { } while (0)
+#define srcu_check_read_flavor_force(ssp, read_flavor) do { } while (0)
/* Defined here to avoid size increase for non-torture kernels. */
static inline void srcu_torture_stats_print(struct srcu_struct *ssp,
diff --git a/include/linux/srcutree.h b/include/linux/srcutree.h
index 6b7eba59f3849..e29cc57eac81d 100644
--- a/include/linux/srcutree.h
+++ b/include/linux/srcutree.h
@@ -251,16 +251,18 @@ static inline void __srcu_read_unlock_lite(struct srcu_struct *ssp, int idx)
void __srcu_check_read_flavor(struct srcu_struct *ssp, int read_flavor);
-// Record _lite() usage even for CONFIG_PROVE_RCU=n kernels.
-static inline void srcu_check_read_flavor_lite(struct srcu_struct *ssp)
+// Record reader usage even for CONFIG_PROVE_RCU=n kernels. This is
+// needed only for flavors that require grace-period smp_mb() calls to be
+// promoted to synchronize_rcu().
+static inline void srcu_check_read_flavor_force(struct srcu_struct *ssp, int read_flavor)
{
struct srcu_data *sdp = raw_cpu_ptr(ssp->sda);
- if (likely(READ_ONCE(sdp->srcu_reader_flavor) & SRCU_READ_FLAVOR_LITE))
+ if (likely(READ_ONCE(sdp->srcu_reader_flavor) & read_flavor))
return;
// Note that the cmpxchg() in __srcu_check_read_flavor() is fully ordered.
- __srcu_check_read_flavor(ssp, SRCU_READ_FLAVOR_LITE);
+ __srcu_check_read_flavor(ssp, read_flavor);
}
// Record non-_lite() usage only for CONFIG_PROVE_RCU=y kernels.
--
2.40.1
