[PATCH 1/3] tools/virtio-trace: Ignore EAGAIN error on splice()

[Masami Hiramatsu (Google)]

splice() can return EAGAIN error instead of returning 0 size read.
In that case, wait a while and try to call splice() again.

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
---
 tools/virtio/virtio-trace/trace-agent-rw.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/tools/virtio/virtio-trace/trace-agent-rw.c b/tools/virtio/virtio-trace/trace-agent-rw.c
index ddfe7875eb16..e8a4c4f0c499 100644
--- a/tools/virtio/virtio-trace/trace-agent-rw.c
+++ b/tools/virtio/virtio-trace/trace-agent-rw.c
@@ -8,6 +8,7 @@
  */
 
 #define _GNU_SOURCE
+#include <errno.h>
 #include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -127,10 +128,10 @@ static void *rw_thread_main(void *thread_info)
 		rlen = splice(ts->in_fd, NULL, ts->read_pipe, NULL,
 				ts->pipe_size, SPLICE_F_MOVE | SPLICE_F_MORE);
 
-		if (rlen < 0) {
-			pr_err("Splice_read in rw-thread(%d)\n", ts->cpu_num);
+		if (rlen < 0 && errno != EAGAIN) {
+			pr_err("Splice_read error (%d) in rw-thread(%d)\n", errno, ts->cpu_num);
 			goto error;
-		} else if (rlen == 0) {
+		} else if (rlen == 0 || errno == EAGAIN) {
 			/*
 			 * If trace data do not exist or are unreadable not
 			 * for exceeding the page size, splice_read returns
-- 
2.34.1


-- 
Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>