The branch main has been updated by rlibby:
URL:
https://cgit.FreeBSD.org/src/commit/?id=ae4a8e52072a87bfd49d553b9b14450c626269f8
commit ae4a8e52072a87bfd49d553b9b14450c626269f8
Author: Ryan Libby <rli...@freebsd.org>
AuthorDate: 2020-12-31 21:02:45 +0000
Commit: Ryan Libby <rli...@freebsd.org>
CommitDate: 2020-12-31 21:02:45 +0000
bitset: implement BIT_TEST_CLR_ATOMIC & BIT_TEST_SET_ATOMIC
That is, provide wrappers around the atomic_testandclear and
atomic_testandset primitives.
Submitted by: jeff
Reviewed by: cem, kib, markj
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D22702
---
share/man/man9/bitset.9 | 14 +++++++++++++-
sys/sys/bitset.h | 14 ++++++++++++++
2 files changed, 27 insertions(+), 1 deletion(-)
diff --git a/share/man/man9/bitset.9 b/share/man/man9/bitset.9
index d597282fea9a..1e080f515788 100644
--- a/share/man/man9/bitset.9
+++ b/share/man/man9/bitset.9
@@ -24,7 +24,7 @@
.\"
.\" $FreeBSD$
.\"
-.Dd August 25, 2020
+.Dd December 31, 2020
.Dt BITSET 9
.Os
.Sh NAME
@@ -60,6 +60,8 @@
.Nm BIT_CLR_ATOMIC ,
.Nm BIT_SET_ATOMIC ,
.Nm BIT_SET_ATOMIC_ACQ ,
+.Nm BIT_TEST_SET_ATOMIC ,
+.Nm BIT_TEST_CLR_ATOMIC ,
.Nm BIT_AND_ATOMIC ,
.Nm BIT_OR_ATOMIC ,
.Nm BIT_COPY_STORE_REL
@@ -137,6 +139,10 @@
.Fn BIT_CLR_ATOMIC "const SETSIZE" "size_t bit" "struct STRUCTNAME *bitset"
.Fn BIT_SET_ATOMIC "const SETSIZE" "size_t bit" "struct STRUCTNAME *bitset"
.Fn BIT_SET_ATOMIC_ACQ "const SETSIZE" "size_t bit" "struct STRUCTNAME *bitset"
+.Ft bool
+.Fn BIT_TEST_SET_ATOMIC "const SETSIZE" "size_t bit" "struct STRUCTNAME
*bitset"
+.Ft bool
+.Fn BIT_TEST_CLR_ATOMIC "const SETSIZE" "size_t bit" "struct STRUCTNAME
*bitset"
.\"
.Fo BIT_AND_ATOMIC
.Fa "const SETSIZE" "struct STRUCTNAME *dst" "struct STRUCTNAME *src"
@@ -205,6 +211,9 @@ in the bitset pointed to by
The
.Fn BIT_CLR_ATOMIC
macro is identical, but the bit is cleared atomically.
+The
+.Fn BIT_TEST_CLR_ATOMIC
+macro atomically clears the bit and returns whether it was set.
.Pp
The
.Fn BIT_COPY
@@ -236,6 +245,9 @@ macro is identical, but the bit is set atomically.
The
.Fn BIT_SET_ATOMIC_ACQ
macro sets the bit with acquire semantics.
+The
+.Fn BIT_TEST_SET_ATOMIC
+macro atomically sets the bit and returns whether it was set.
.Pp
The
.Fn BIT_ZERO
diff --git a/sys/sys/bitset.h b/sys/sys/bitset.h
index 97f18def7236..2b5df78a8193 100644
--- a/sys/sys/bitset.h
+++ b/sys/sys/bitset.h
@@ -173,6 +173,12 @@
(d)->__bits[__i] = (s1)->__bits[__i] ^ (s2)->__bits[__i];\
} while (0)
+/*
+ * Note, the atomic(9) API is not consistent between clear/set and
+ * testandclear/testandset in whether the value argument is a mask
+ * or a bit index.
+ */
+
#define BIT_CLR_ATOMIC(_s, n, p)
\
atomic_clear_long(&(p)->__bits[__bitset_word(_s, n)], \
__bitset_mask((_s), n))
@@ -185,6 +191,14 @@
atomic_set_acq_long(&(p)->__bits[__bitset_word(_s, n)], \
__bitset_mask((_s), n))
+#define BIT_TEST_CLR_ATOMIC(_s, n, p)
\
+ (atomic_testandclear_long( \
+ &(p)->__bits[__bitset_word((_s), (n))], (n)) != 0)
+
+#define BIT_TEST_SET_ATOMIC(_s, n, p)
\
+ (atomic_testandset_long( \
+ &(p)->__bits[__bitset_word((_s), (n))], (n)) != 0)
+
/* Convenience functions catering special cases. */
#define BIT_AND_ATOMIC(_s, d, s) do {
\
__size_t __i; \
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