Patchwork [v2,2/2] sheepdog: set io_flush handler in do_co_req

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Submitter MORITA Kazutaka
Date March 12, 2013, 7:05 a.m.
Message ID <1363071943-29248-3-git-send-email-morita.kazutaka@lab.ntt.co.jp>
Download mbox | patch
Permalink /patch/226825/
State New
Headers show

Comments

MORITA Kazutaka - March 12, 2013, 7:05 a.m.
If an io_flush handler is not set, qemu_aio_wait doesn't invoke
callbacks.

Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
---
 block/sheepdog.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

Patch

diff --git a/block/sheepdog.c b/block/sheepdog.c
index 27abef2..4245328 100644
--- a/block/sheepdog.c
+++ b/block/sheepdog.c
@@ -501,6 +501,13 @@  static void restart_co_req(void *opaque)
     qemu_coroutine_enter(co, NULL);
 }
 
+static int have_co_req(void *opaque)
+{
+    /* this handler is set only when there is a pending request, so
+     * always returns 1. */
+    return 1;
+}
+
 typedef struct SheepdogReqCo {
     int sockfd;
     SheepdogReq *hdr;
@@ -523,14 +530,14 @@  static coroutine_fn void do_co_req(void *opaque)
     unsigned int *rlen = srco->rlen;
 
     co = qemu_coroutine_self();
-    qemu_aio_set_fd_handler(sockfd, NULL, restart_co_req, NULL, co);
+    qemu_aio_set_fd_handler(sockfd, NULL, restart_co_req, have_co_req, co);
 
     ret = send_co_req(sockfd, hdr, data, wlen);
     if (ret < 0) {
         goto out;
     }
 
-    qemu_aio_set_fd_handler(sockfd, restart_co_req, NULL, NULL, co);
+    qemu_aio_set_fd_handler(sockfd, restart_co_req, NULL, have_co_req, co);
 
     ret = qemu_co_recv(sockfd, hdr, sizeof(*hdr));
     if (ret < sizeof(*hdr)) {
@@ -553,6 +560,8 @@  static coroutine_fn void do_co_req(void *opaque)
     }
     ret = 0;
 out:
+    /* there is at most one request for this sockfd, so it is safe to
+     * set each handler to NULL. */
     qemu_aio_set_fd_handler(sockfd, NULL, NULL, NULL, NULL);
 
     srco->ret = ret;