[PATCH 4/6] move the aio_ring defintion and empty check into a header

[Christoph Hellwig <hch@lst.de>]

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 src/aio_ring.h     | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 src/io_getevents.c | 28 +++-------------------------
 2 files changed, 52 insertions(+), 25 deletions(-)
 create mode 100644 src/aio_ring.h

diff --git a/src/aio_ring.h b/src/aio_ring.h
new file mode 100644
index 0000000..3842c4b
--- /dev/null
+++ b/src/aio_ring.h
@@ -0,0 +1,49 @@
+/*
+   libaio Linux async I/O interface
+   Copyright 2002 Red Hat, Inc.
+
+   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; either
+   version 2 of the License, or (at your option) any later version.
+
+   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., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
+ */
+#ifndef _AIO_RING_H
+#define _AIO_RING_H
+
+#define AIO_RING_MAGIC                  0xa10a10a1
+
+struct aio_ring {
+	unsigned        id;     /* kernel internal index number */
+	unsigned        nr;     /* number of io_events */
+	unsigned        head;
+	unsigned        tail;
+
+	unsigned        magic;
+	unsigned        compat_features;
+	unsigned        incompat_features;
+	unsigned        header_length;  /* size of aio_ring */
+};
+
+static inline int aio_ring_is_empty(io_context_t ctx, struct timespec *timeout)
+{
+	struct aio_ring *ring = (struct aio_ring *)ctx;
+
+	if (!ring || ring->magic != AIO_RING_MAGIC)
+		return 0;
+	if (!timeout || timeout->tv_sec || timeout->tv_nsec)
+		return 0;
+	if (ring->head != ring->tail)
+		return 0;
+	return 1;
+}
+
+#endif /* _AIO_RING_H */
diff --git a/src/io_getevents.c b/src/io_getevents.c
index 5a05174..90d6081 100644
--- a/src/io_getevents.c
+++ b/src/io_getevents.c
@@ -21,36 +21,14 @@
 #include <stdlib.h>
 #include <time.h>
 #include "syscall.h"
+#include "aio_ring.h"
 
 io_syscall5(int, __io_getevents_0_4, io_getevents, io_context_t, ctx, long, min_nr, long, nr, struct io_event *, events, struct timespec *, timeout)
 
-#define AIO_RING_MAGIC                  0xa10a10a1
-
-/* Ben will hate me for this */
-struct aio_ring {
-	unsigned        id;     /* kernel internal index number */
-	unsigned        nr;     /* number of io_events */
-	unsigned        head;
-	unsigned        tail;
- 
-	unsigned        magic;
-	unsigned        compat_features;
-	unsigned        incompat_features;
-	unsigned        header_length;  /* size of aio_ring */
-};
-
 int io_getevents_0_4(io_context_t ctx, long min_nr, long nr, struct io_event * events, struct timespec * timeout)
 {
-	struct aio_ring *ring;
-	ring = (struct aio_ring*)ctx;
-	if (ring==NULL || ring->magic != AIO_RING_MAGIC)
-		goto do_syscall;
-	if (timeout!=NULL && timeout->tv_sec == 0 && timeout->tv_nsec == 0) {
-		if (ring->head == ring->tail)
-			return 0;
-	}
-	
-do_syscall:	
+	if (aio_ring_is_empty(ctx, timeout))
+		return 0;
 	return __io_getevents_0_4(ctx, min_nr, nr, events, timeout);
 }
 
-- 
2.14.2

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