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GET /api/patches/1525721/?format=api
{ "id": 1525721, "url": "http://patchwork.ozlabs.org/api/patches/1525721/?format=api", "web_url": "http://patchwork.ozlabs.org/project/openvswitch/patch/38c9b941c662fc08a47f5759a3e6b32267212590.1631094144.git.grive@u256.net/", "project": { "id": 47, "url": "http://patchwork.ozlabs.org/api/projects/47/?format=api", "name": "Open vSwitch", "link_name": "openvswitch", "list_id": "ovs-dev.openvswitch.org", "list_email": "ovs-dev@openvswitch.org", "web_url": "http://openvswitch.org/", "scm_url": "git@github.com:openvswitch/ovs.git", "webscm_url": "https://github.com/openvswitch/ovs", "list_archive_url": "", "list_archive_url_format": "", "commit_url_format": "" }, "msgid": "<38c9b941c662fc08a47f5759a3e6b32267212590.1631094144.git.grive@u256.net>", "list_archive_url": null, "date": "2021-09-08T09:47:35", "name": "[ovs-dev,v5,11/27] ovs-atomic: Expose atomic exchange operation", "commit_ref": "5878b9252209528d04c481c425f4bd41ab7943b6", "pull_url": null, "state": "accepted", "archived": false, "hash": "83f9741c1a040605cf414bb3d934fb9f12b89f85", "submitter": { "id": 78795, "url": "http://patchwork.ozlabs.org/api/people/78795/?format=api", "name": "Gaetan Rivet", "email": "grive@u256.net" }, "delegate": null, "mbox": "http://patchwork.ozlabs.org/project/openvswitch/patch/38c9b941c662fc08a47f5759a3e6b32267212590.1631094144.git.grive@u256.net/mbox/", "series": [ { "id": 261424, "url": "http://patchwork.ozlabs.org/api/series/261424/?format=api", "web_url": "http://patchwork.ozlabs.org/project/openvswitch/list/?series=261424", "date": "2021-09-08T09:47:24", "name": "dpif-netdev: Parallel offload processing", "version": 5, "mbox": "http://patchwork.ozlabs.org/series/261424/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/patches/1525721/comments/", "check": "success", "checks": "http://patchwork.ozlabs.org/api/patches/1525721/checks/", "tags": {}, "related": [], "headers": { "Return-Path": "<ovs-dev-bounces@openvswitch.org>", "X-Original-To": [ "incoming@patchwork.ozlabs.org", "ovs-dev@openvswitch.org" ], "Delivered-To": [ "patchwork-incoming@bilbo.ozlabs.org", "ovs-dev@lists.linuxfoundation.org" ], "Authentication-Results": [ "ozlabs.org;\n\tdkim=fail reason=\"signature verification failed\" (2048-bit key;\n unprotected) header.d=u256.net header.i=@u256.net header.a=rsa-sha256\n header.s=fm2 header.b=wumMUmwI;\n\tdkim=fail reason=\"signature verification failed\" (2048-bit key;\n unprotected) header.d=messagingengine.com header.i=@messagingengine.com\n header.a=rsa-sha256 header.s=fm3 header.b=IQzpW0lh;\n\tdkim-atps=neutral", "ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=openvswitch.org\n (client-ip=140.211.166.137; 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charset=\"us-ascii\"", "Content-Transfer-Encoding": "7bit", "Errors-To": "ovs-dev-bounces@openvswitch.org", "Sender": "\"dev\" <ovs-dev-bounces@openvswitch.org>" }, "content": "The atomic exchange operation is a useful primitive that should be\navailable as well. Most compilers already expose or offer a way\nto use it, but a single symbol needs to be defined.\n\nSigned-off-by: Gaetan Rivet <grive@u256.net>\nReviewed-by: Eli Britstein <elibr@nvidia.com>\nReviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>\n---\n lib/ovs-atomic-c++.h | 3 +++\n lib/ovs-atomic-clang.h | 5 +++++\n lib/ovs-atomic-gcc4+.h | 5 +++++\n lib/ovs-atomic-gcc4.7+.h | 5 +++++\n lib/ovs-atomic-i586.h | 5 +++++\n lib/ovs-atomic-locked.h | 9 +++++++++\n lib/ovs-atomic-msvc.h | 22 ++++++++++++++++++++++\n lib/ovs-atomic-pthreads.h | 5 +++++\n lib/ovs-atomic-x86_64.h | 5 +++++\n lib/ovs-atomic.h | 8 +++++++-\n 10 files changed, 71 insertions(+), 1 deletion(-)", "diff": "diff --git a/lib/ovs-atomic-c++.h b/lib/ovs-atomic-c++.h\nindex d47b8dd39..8605fa9d3 100644\n--- a/lib/ovs-atomic-c++.h\n+++ b/lib/ovs-atomic-c++.h\n@@ -29,6 +29,9 @@ using std::atomic_compare_exchange_strong_explicit;\n using std::atomic_compare_exchange_weak;\n using std::atomic_compare_exchange_weak_explicit;\n \n+using std::atomic_exchange;\n+using std::atomic_exchange_explicit;\n+\n #define atomic_read(SRC, DST) \\\n atomic_read_explicit(SRC, DST, memory_order_seq_cst)\n #define atomic_read_explicit(SRC, DST, ORDER) \\\ndiff --git a/lib/ovs-atomic-clang.h b/lib/ovs-atomic-clang.h\nindex 34cc2faa7..cdf02a512 100644\n--- a/lib/ovs-atomic-clang.h\n+++ b/lib/ovs-atomic-clang.h\n@@ -67,6 +67,11 @@ typedef enum {\n #define atomic_compare_exchange_weak_explicit(DST, EXP, SRC, ORD1, ORD2) \\\n __c11_atomic_compare_exchange_weak(DST, EXP, SRC, ORD1, ORD2)\n \n+#define atomic_exchange(RMW, ARG) \\\n+ atomic_exchange_explicit(RMW, ARG, memory_order_seq_cst)\n+#define atomic_exchange_explicit(RMW, ARG, ORDER) \\\n+ __c11_atomic_exchange(RMW, ARG, ORDER)\n+\n #define atomic_add(RMW, ARG, ORIG) \\\n atomic_add_explicit(RMW, ARG, ORIG, memory_order_seq_cst)\n #define atomic_sub(RMW, ARG, ORIG) \\\ndiff --git a/lib/ovs-atomic-gcc4+.h b/lib/ovs-atomic-gcc4+.h\nindex 25bcf20a0..f9accde1a 100644\n--- a/lib/ovs-atomic-gcc4+.h\n+++ b/lib/ovs-atomic-gcc4+.h\n@@ -128,6 +128,11 @@ atomic_signal_fence(memory_order order)\n #define atomic_compare_exchange_weak_explicit \\\n atomic_compare_exchange_strong_explicit\n \n+#define atomic_exchange_explicit(DST, SRC, ORDER) \\\n+ __sync_lock_test_and_set(DST, SRC)\n+#define atomic_exchange(DST, SRC) \\\n+ atomic_exchange_explicit(DST, SRC, memory_order_seq_cst)\n+\n #define atomic_op__(RMW, OP, ARG, ORIG) \\\n ({ \\\n typeof(RMW) rmw__ = (RMW); \\\ndiff --git a/lib/ovs-atomic-gcc4.7+.h b/lib/ovs-atomic-gcc4.7+.h\nindex 4c197ebe0..846e05775 100644\n--- a/lib/ovs-atomic-gcc4.7+.h\n+++ b/lib/ovs-atomic-gcc4.7+.h\n@@ -61,6 +61,11 @@ typedef enum {\n #define atomic_compare_exchange_weak_explicit(DST, EXP, SRC, ORD1, ORD2) \\\n __atomic_compare_exchange_n(DST, EXP, SRC, true, ORD1, ORD2)\n \n+#define atomic_exchange_explicit(DST, SRC, ORDER) \\\n+ __atomic_exchange_n(DST, SRC, ORDER)\n+#define atomic_exchange(DST, SRC) \\\n+ atomic_exchange_explicit(DST, SRC, memory_order_seq_cst)\n+\n #define atomic_add(RMW, OPERAND, ORIG) \\\n atomic_add_explicit(RMW, OPERAND, ORIG, memory_order_seq_cst)\n #define atomic_sub(RMW, OPERAND, ORIG) \\\ndiff --git a/lib/ovs-atomic-i586.h b/lib/ovs-atomic-i586.h\nindex 9a385ce84..35a0959ff 100644\n--- a/lib/ovs-atomic-i586.h\n+++ b/lib/ovs-atomic-i586.h\n@@ -400,6 +400,11 @@ atomic_signal_fence(memory_order order)\n #define atomic_compare_exchange_weak_explicit \\\n atomic_compare_exchange_strong_explicit\n \n+#define atomic_exchange_explicit(RMW, ARG, ORDER) \\\n+ atomic_exchange__(RMW, ARG, ORDER)\n+#define atomic_exchange(RMW, ARG) \\\n+ atomic_exchange_explicit(RMW, ARG, memory_order_seq_cst)\n+\n #define atomic_add__(RMW, ARG, CLOB) \\\n asm volatile(\"lock; xadd %0,%1 ; \" \\\n \"# atomic_add__ \" \\\ndiff --git a/lib/ovs-atomic-locked.h b/lib/ovs-atomic-locked.h\nindex f8f0ba2a5..bf38c4a43 100644\n--- a/lib/ovs-atomic-locked.h\n+++ b/lib/ovs-atomic-locked.h\n@@ -31,6 +31,15 @@ void atomic_unlock__(void *);\n atomic_unlock__(DST), \\\n false)))\n \n+#define atomic_exchange_locked(DST, SRC) \\\n+ ({ \\\n+ atomic_lock__(DST); \\\n+ typeof(*(DST)) __tmp = *(DST); \\\n+ *(DST) = SRC; \\\n+ atomic_unlock__(DST); \\\n+ __tmp; \\\n+ })\n+\n #define atomic_op_locked_add +=\n #define atomic_op_locked_sub -=\n #define atomic_op_locked_or |=\ndiff --git a/lib/ovs-atomic-msvc.h b/lib/ovs-atomic-msvc.h\nindex 9def887d3..ef8310269 100644\n--- a/lib/ovs-atomic-msvc.h\n+++ b/lib/ovs-atomic-msvc.h\n@@ -345,6 +345,28 @@ atomic_signal_fence(memory_order order)\n #define atomic_compare_exchange_weak_explicit \\\n atomic_compare_exchange_strong_explicit\n \n+/* While intrinsics offering different memory ordering\n+ * are available in MSVC C compiler, they are not defined\n+ * in the C++ compiler. Ignore for compatibility.\n+ *\n+ * Use nested ternary operators as the GNU extension ({})\n+ * is not available.\n+ */\n+\n+#define atomic_exchange_explicit(DST, SRC, ORDER) \\\n+ ((sizeof *(DST) == 1) ? \\\n+ _InterlockedExchange8((char volatile *) DST, SRC) \\\n+ : (sizeof *(DST) == 2) ? \\\n+ _InterlockedExchange16((short volatile *) DST, SRC) \\\n+ : (sizeof *(DST) == 4) ? \\\n+ _InterlockedExchange((long int volatile *) DST, SRC) \\\n+ : (sizeof *(DST) == 8) ? \\\n+ _InterlockedExchange64((__int64 volatile *) DST, SRC) \\\n+ : (ovs_abort(), 0))\n+\n+#define atomic_exchange(DST, SRC) \\\n+ atomic_exchange_explicit(DST, SRC, memory_order_seq_cst)\n+\n /* MSVCs c++ compiler implements c11 atomics and looking through its\n * implementation (in xatomic.h), orders are ignored for x86 platform.\n * Do the same here. */\ndiff --git a/lib/ovs-atomic-pthreads.h b/lib/ovs-atomic-pthreads.h\nindex 12234e79e..570a67fe4 100644\n--- a/lib/ovs-atomic-pthreads.h\n+++ b/lib/ovs-atomic-pthreads.h\n@@ -77,6 +77,11 @@ atomic_signal_fence(memory_order order OVS_UNUSED)\n #define atomic_compare_exchange_weak_explicit \\\n atomic_compare_exchange_strong_explicit\n \n+#define atomic_exchange(DST, SRC) \\\n+ atomic_exchange_locked(DST, SRC)\n+#define atomic_exchange_explicit(DST, SRC, ORDER) \\\n+ ((void) (ORDER), atomic_exchange(DST, SRC))\n+\n #define atomic_add(RMW, ARG, ORIG) atomic_op_locked(RMW, add, ARG, ORIG)\n #define atomic_sub(RMW, ARG, ORIG) atomic_op_locked(RMW, sub, ARG, ORIG)\n #define atomic_or( RMW, ARG, ORIG) atomic_op_locked(RMW, or, ARG, ORIG)\ndiff --git a/lib/ovs-atomic-x86_64.h b/lib/ovs-atomic-x86_64.h\nindex 1e7d42707..3bdaf2f08 100644\n--- a/lib/ovs-atomic-x86_64.h\n+++ b/lib/ovs-atomic-x86_64.h\n@@ -274,6 +274,11 @@ atomic_signal_fence(memory_order order)\n #define atomic_compare_exchange_weak_explicit \\\n atomic_compare_exchange_strong_explicit\n \n+#define atomic_exchange_explicit(RMW, ARG, ORDER) \\\n+ atomic_exchange__(RMW, ARG, ORDER)\n+#define atomic_exchange(RMW, ARG) \\\n+ atomic_exchange_explicit(RMW, ARG, memory_order_seq_cst)\n+\n #define atomic_add__(RMW, ARG, CLOB) \\\n asm volatile(\"lock; xadd %0,%1 ; \" \\\n \"# atomic_add__ \" \\\ndiff --git a/lib/ovs-atomic.h b/lib/ovs-atomic.h\nindex 11fa19268..8fdce0cf8 100644\n--- a/lib/ovs-atomic.h\n+++ b/lib/ovs-atomic.h\n@@ -210,7 +210,7 @@\n * In this section, A is an atomic type and C is the corresponding non-atomic\n * type.\n *\n- * The \"store\" and \"compare_exchange\" primitives match C11:\n+ * The \"store\", \"exchange\", and \"compare_exchange\" primitives match C11:\n *\n * void atomic_store(A *object, C value);\n * void atomic_store_explicit(A *object, C value, memory_order);\n@@ -244,6 +244,12 @@\n * efficiently, so it should be used if the application will need to\n * loop anyway.\n *\n+ * C atomic_exchange(A *object, C desired);\n+ * C atomic_exchange_explicit(A *object, C desired, memory_order);\n+ *\n+ * Atomically stores 'desired' into '*object', returning the value\n+ * previously held.\n+ *\n * The following primitives differ from the C11 ones (and have different names)\n * because there does not appear to be a way to implement the standard\n * primitives in standard C:\n", "prefixes": [ "ovs-dev", "v5", "11/27" ] }