X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=lib%2Fringbuffer%2Fbackend_internal.h;h=aec5298dda75503227ffda4cdb973dd440e4bb01;hb=5760f3f4e64af16249a4f208e680c7dcffb4f990;hp=e03d8c0b1b23a1363fdebbe5ed8589223226983c;hpb=85a07c33f3b180d9c1be38832961d0feef66be66;p=lttng-modules.git

diff --git a/lib/ringbuffer/backend_internal.h b/lib/ringbuffer/backend_internal.h
index e03d8c0b..aec5298d 100644
--- a/lib/ringbuffer/backend_internal.h
+++ b/lib/ringbuffer/backend_internal.h
@@ -1,31 +1,19 @@
-#ifndef _LIB_RING_BUFFER_BACKEND_INTERNAL_H
-#define _LIB_RING_BUFFER_BACKEND_INTERNAL_H
-
-/*
+/* SPDX-License-Identifier: (GPL-2.0-only OR LGPL-2.1-only)
+ *
  * lib/ringbuffer/backend_internal.h
  *
  * Ring buffer backend (internal helpers).
  *
  * Copyright (C) 2008-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; only
- * version 2.1 of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
-#include <wrapper/ringbuffer/config.h>
-#include <wrapper/ringbuffer/backend_types.h>
-#include <wrapper/ringbuffer/frontend_types.h>
+#ifndef _LIB_RING_BUFFER_BACKEND_INTERNAL_H
+#define _LIB_RING_BUFFER_BACKEND_INTERNAL_H
+
+#include <wrapper/compiler.h>
+#include <include/ringbuffer/config.h>
+#include <include/ringbuffer/backend_types.h>
+#include <include/ringbuffer/frontend_types.h>
 #include <linux/string.h>
 #include <linux/uaccess.h>
 
@@ -171,7 +159,7 @@ void subbuffer_id_set_noref_offset(const struct lib_ring_buffer_config *config,
 		tmp |= offset << SB_ID_OFFSET_SHIFT;
 		tmp |= SB_ID_NOREF_MASK;
 		/* Volatile store, read concurrently by readers. */
-		ACCESS_ONCE(*id) = tmp;
+		WRITE_ONCE(*id, tmp);
 	}
 }
 
@@ -379,7 +367,7 @@ void lib_ring_buffer_clear_noref(const struct lib_ring_buffer_config *config,
 	 * Performing a volatile access to read the sb_pages, because we want to
 	 * read a coherent version of the pointer and the associated noref flag.
 	 */
-	id = ACCESS_ONCE(bufb->buf_wsb[idx].id);
+	id = READ_ONCE(bufb->buf_wsb[idx].id);
 	for (;;) {
 		/* This check is called on the fast path for each record. */
 		if (likely(!subbuffer_id_is_noref(config, id))) {
@@ -448,7 +436,7 @@ int update_read_sb_index(const struct lib_ring_buffer_config *config,
 	if (config->mode == RING_BUFFER_OVERWRITE) {
 		/*
 		 * Exchange the target writer subbuffer with our own unused
-		 * subbuffer. No need to use ACCESS_ONCE() here to read the
+		 * subbuffer. No need to use READ_ONCE() here to read the
 		 * old_wpage, because the value read will be confirmed by the
 		 * following cmpxchg().
 		 */
@@ -478,6 +466,28 @@ int update_read_sb_index(const struct lib_ring_buffer_config *config,
 	return 0;
 }
 
+static inline __attribute__((always_inline))
+void lttng_inline_memcpy(void *dest, const void *src,
+		unsigned long len)
+{
+	switch (len) {
+	case 1:
+		*(uint8_t *) dest = *(const uint8_t *) src;
+		break;
+	case 2:
+		*(uint16_t *) dest = *(const uint16_t *) src;
+		break;
+	case 4:
+		*(uint32_t *) dest = *(const uint32_t *) src;
+		break;
+	case 8:
+		*(uint64_t *) dest = *(const uint64_t *) src;
+		break;
+	default:
+		memcpy(dest, src, len);
+	}
+}
+
 /*
  * Use the architecture-specific memcpy implementation for constant-sized
  * inputs, but rely on an inline memcpy for length statically unknown.
@@ -489,7 +499,7 @@ do {								\
 	if (__builtin_constant_p(len))				\
 		memcpy(dest, src, __len);			\
 	else							\
-		inline_memcpy(dest, src, __len);		\
+		lttng_inline_memcpy(dest, src, __len);		\
 } while (0)
 
 /*