[PATCH rcu 08/20] srcu: Rename srcu_check_read_flavor_lite() to srcu_check_read_flavor_force()

[Boqun Feng]

From: "Paul E. McKenney" <paul...@kernel.org>

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 <paul...@kernel.org>
Cc: Alexei Starovoitov <a...@kernel.org>
Cc: Andrii Nakryiko <and...@kernel.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Kent Overstreet <kent.overstr...@linux.dev>
Cc: <b...@vger.kernel.org>
Signed-off-by: Boqun Feng <boqun.f...@gmail.com>
---
 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 f6f779b9d9ff..ca00b9af7c23 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 1321da803274..b347bde1aac2 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 6b7eba59f384..e29cc57eac81 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.
-- 
2.39.5 (Apple Git-154)