This patch avoids that multiple definitions of barrier primitives occur in
the tools directory. This patch does not change the behavior of the code on
x86 since on x86 smp_rmb() and smp_wmb() are defined as follows in
tools/arch/x86/include/asm/barrier.h:
#define barrier() __asm__ __volatile__("": : :"memory")
#define smp_rmb() barrier()
#define smp_wmb() barrier()
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
---
tools/io_uring/barrier.h | 16 ----------------
tools/io_uring/io_uring-bench.c | 12 ++++++------
tools/io_uring/liburing.h | 4 ++--
tools/io_uring/queue.c | 14 +++++++-------
4 files changed, 15 insertions(+), 31 deletions(-)
delete mode 100644 tools/io_uring/barrier.h
diff --git a/tools/io_uring/barrier.h b/tools/io_uring/barrier.h
deleted file mode 100644
index ef00f6722ba9..000000000000
--- a/tools/io_uring/barrier.h
+++ /dev/null
@@ -1,16 +0,0 @@
-#ifndef LIBURING_BARRIER_H
-#define LIBURING_BARRIER_H
-
-#if defined(__x86_64) || defined(__i386__)
-#define read_barrier() __asm__ __volatile__("":::"memory")
-#define write_barrier() __asm__ __volatile__("":::"memory")
-#else
-/*
- * Add arch appropriate definitions. Be safe and use full barriers for
- * archs we don't have support for.
- */
-#define read_barrier() __sync_synchronize()
-#define write_barrier() __sync_synchronize()
-#endif
-
-#endif
diff --git a/tools/io_uring/io_uring-bench.c b/tools/io_uring/io_uring-bench.c
index 0f257139b003..3ce715247c5e 100644
--- a/tools/io_uring/io_uring-bench.c
+++ b/tools/io_uring/io_uring-bench.c
@@ -28,9 +28,9 @@
#include <string.h>
#include <pthread.h>
#include <sched.h>
+#include <asm/barrier.h>
#include "liburing.h"
-#include "barrier.h"
#define min(a, b) ((a < b) ? (a) : (b))
@@ -199,7 +199,7 @@ static int prep_more_ios(struct submitter *s, unsigned max_ios)
next_tail = tail = *ring->tail;
do {
next_tail++;
- read_barrier();
+ smp_rmb();
if (next_tail == *ring->head)
break;
@@ -212,9 +212,9 @@ static int prep_more_ios(struct submitter *s, unsigned max_ios)
if (*ring->tail != tail) {
/* order tail store with writes to sqes above */
- write_barrier();
+ smp_wmb();
*ring->tail = tail;
- write_barrier();
+ smp_wmb();
}
return prepped;
}
@@ -251,7 +251,7 @@ static int reap_events(struct submitter *s)
do {
struct file *f;
- read_barrier();
+ smp_rmb();
if (head == *ring->tail)
break;
cqe = &ring->cqes[head & cq_ring_mask];
@@ -271,7 +271,7 @@ static int reap_events(struct submitter *s)
s->inflight -= reaped;
*ring->head = head;
- write_barrier();
+ smp_wmb();
return reaped;
}
diff --git a/tools/io_uring/liburing.h b/tools/io_uring/liburing.h
index 5f305c86b892..3670a08101c7 100644
--- a/tools/io_uring/liburing.h
+++ b/tools/io_uring/liburing.h
@@ -10,7 +10,7 @@ extern "C" {
#include <string.h>
#include "../../include/uapi/linux/io_uring.h"
#include <inttypes.h>
-#include "barrier.h"
+#include <asm/barrier.h>
/*
* Library interface to io_uring
@@ -87,7 +87,7 @@ static inline void io_uring_cqe_seen(struct io_uring *ring,
* Ensure that the kernel sees our new head, the kernel has
* the matching read barrier.
*/
- write_barrier();
+ smp_wmb();
}
}
diff --git a/tools/io_uring/queue.c b/tools/io_uring/queue.c
index 321819c132c7..aadf4d926c8e 100644
--- a/tools/io_uring/queue.c
+++ b/tools/io_uring/queue.c
@@ -4,9 +4,9 @@
#include <unistd.h>
#include <errno.h>
#include <string.h>
+#include <asm/barrier.h>
#include "liburing.h"
-#include "barrier.h"
static int __io_uring_get_cqe(struct io_uring *ring,
struct io_uring_cqe **cqe_ptr, int wait)
@@ -20,13 +20,13 @@ static int __io_uring_get_cqe(struct io_uring *ring,
head = *cq->khead;
do {
/*
- * It's necessary to use a read_barrier() before reading
+ * It's necessary to use a smp_rmb() before reading
* the CQ tail, since the kernel updates it locklessly. The
* kernel has the matching store barrier for the update. The
* kernel also ensures that previous stores to CQEs are ordered
* with the tail update.
*/
- read_barrier();
+ smp_rmb();
if (head != *cq->ktail) {
*cqe_ptr = &cq->cqes[head & mask];
break;
@@ -77,7 +77,7 @@ int io_uring_submit(struct io_uring *ring)
* read barrier here to match the kernels store barrier when updating
* the SQ head.
*/
- read_barrier();
+ smp_rmb();
if (*sq->khead != *sq->ktail) {
submitted = *sq->kring_entries;
goto submit;
@@ -94,7 +94,7 @@ int io_uring_submit(struct io_uring *ring)
to_submit = sq->sqe_tail - sq->sqe_head;
while (to_submit--) {
ktail_next++;
- read_barrier();
+ smp_rmb();
sq->array[ktail & mask] = sq->sqe_head & mask;
ktail = ktail_next;
@@ -113,13 +113,13 @@ int io_uring_submit(struct io_uring *ring)
* will never see a tail update without the preceeding sQE
* stores being done.
*/
- write_barrier();
+ smp_wmb();
*sq->ktail = ktail;
/*
* The kernel has the matching read barrier for reading the
* SQ tail.
*/
- write_barrier();
+ smp_wmb();
}
submit:
--
2.22.0.410.gd8fdbe21b5-goog
