git: 65f775157e0d - main - seqc: add seqc_read_notmodify

[Mateusz Guzik]

The branch main has been updated by mjg:

URL: https://cgit.FreeBSD.org/src/commit/?id=65f775157e0d239f311e912086600f620d0c15cf

commit 65f775157e0d239f311e912086600f620d0c15cf
Author:     Mateusz Guzik <mjg at FreeBSD.org>
AuthorDate: 2021-01-06 06:11:15 +0000
Commit:     Mateusz Guzik <mjg at FreeBSD.org>
CommitDate: 2021-01-06 07:28:06 +0000

    seqc: add seqc_read_notmodify
    
    The routine can be used when the caller does not expect to ever have to
    wait for anything. Checking later with seqc_consistent retains all the
    guarantees.
---
 sys/sys/seqc.h | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/sys/sys/seqc.h b/sys/sys/seqc.h
index a04e342ad7d3..3cfaaf3acbda 100644
--- a/sys/sys/seqc.h
+++ b/sys/sys/seqc.h
@@ -81,6 +81,13 @@ seqc_read_any(const seqc_t *seqcp)
 	return (atomic_load_acq_int(__DECONST(seqc_t *, seqcp)));
 }
 
+static __inline seqc_t
+seqc_read_notmodify(const seqc_t *seqcp)
+{
+
+	return (atomic_load_acq_int(__DECONST(seqc_t *, seqcp)) & ~1);
+}
+
 static __inline seqc_t
 seqc_read(const seqc_t *seqcp)
 {