[Qemu-devel] [PATCH 08/12] Threadlet: Add aio_signal_handler threadlet API

[Arun R Bharadwaj <arun@linux.vnet.ibm.com>]

This patch adds aio_signal_handler threadlet API. Earler
posix-aio-compat.c had its own signal handler code. Now
abstract this, in the later patch it is moved to a generic
code so that it can be used by other subsystems.

Signed-off-by: Arun R Bharadwaj <arun@linux.vnet.ibm.com>
---
 posix-aio-compat.c |   49 +++++++++++++++++++++++++++----------------------
 qemu-thread.h      |    1 +
 vl.c               |    3 +++
 3 files changed, 31 insertions(+), 22 deletions(-)

diff --git a/posix-aio-compat.c b/posix-aio-compat.c
index 8c5bb46..94dd007 100644
--- a/posix-aio-compat.c
+++ b/posix-aio-compat.c
@@ -327,11 +327,14 @@ static void *threadlet_worker(void *data)
     return NULL;
 }
 
+static PosixAioState *posix_aio_state;
+
 static void handle_work(ThreadletWork *work)
 {
     pid_t pid;
     ssize_t ret = 0;
     struct qemu_paiocb *aiocb;
+    char byte = 0;
 
     pid = getpid();
     qemu_mutex_lock(&aiocb_mutex);
@@ -360,11 +363,35 @@ static void handle_work(ThreadletWork *work)
     qemu_cond_broadcast(&aiocb_completion);
     qemu_mutex_unlock(&aiocb_mutex);
 
+    ret = write(posix_aio_state->wfd, &byte, sizeof(byte));
+    if (ret < 0 && errno != EAGAIN) {
+        die("write()");
+    }
+
     if (kill(pid, aiocb->ev_signo)) {
         die("kill failed");
     }
 }
 
+static void threadlet_io_completion_signal_handler(int signum)
+{
+    qemu_service_io();
+}
+
+static void threadlet_register_signal_handler(void)
+{
+    struct sigaction act;
+    sigfillset(&act.sa_mask);
+    act.sa_flags = 0; /* do not restart syscalls to interrupt select() */
+    act.sa_handler = threadlet_io_completion_signal_handler;
+    sigaction(SIGUSR2, &act, NULL);
+}
+
+void threadlet_init(void)
+{
+    threadlet_register_signal_handler();
+}
+
 static void spawn_threadlet(ThreadletQueue *queue)
 {
     QemuThread thread;
@@ -520,22 +547,6 @@ static int posix_aio_flush(void *opaque)
     return !!s->first_aio;
 }
 
-static PosixAioState *posix_aio_state;
-
-static void aio_signal_handler(int signum)
-{
-    if (posix_aio_state) {
-        char byte = 0;
-        ssize_t ret;
-
-        ret = write(posix_aio_state->wfd, &byte, sizeof(byte));
-        if (ret < 0 && errno != EAGAIN)
-            die("write()");
-    }
-
-    qemu_service_io();
-}
-
 static void paio_remove(struct qemu_paiocb *acb)
 {
     struct qemu_paiocb **pacb;
@@ -642,7 +653,6 @@ BlockDriverAIOCB *paio_ioctl(BlockDriverState *bs, int fd,
 
 int paio_init(void)
 {
-    struct sigaction act;
     PosixAioState *s;
     int fds[2];
 
@@ -654,11 +664,6 @@ int paio_init(void)
 
     s = qemu_malloc(sizeof(PosixAioState));
 
-    sigfillset(&act.sa_mask);
-    act.sa_flags = 0; /* do not restart syscalls to interrupt select() */
-    act.sa_handler = aio_signal_handler;
-    sigaction(SIGUSR2, &act, NULL);
-
     s->first_aio = NULL;
     if (qemu_pipe(fds) == -1) {
         fprintf(stderr, "failed to create pipe\n");
diff --git a/qemu-thread.h b/qemu-thread.h
index 19bb30c..c5b579c 100644
--- a/qemu-thread.h
+++ b/qemu-thread.h
@@ -40,5 +40,6 @@ void qemu_thread_signal(QemuThread *thread, int sig);
 void qemu_thread_self(QemuThread *thread);
 int qemu_thread_equal(QemuThread *thread1, QemuThread *thread2);
 void qemu_thread_exit(void *retval);
+void threadlet_init(void);
 
 #endif
diff --git a/vl.c b/vl.c
index df414ef..aba805f 100644
--- a/vl.c
+++ b/vl.c
@@ -148,6 +148,7 @@ int main(int argc, char **argv)
 #include "qemu-config.h"
 #include "qemu-objects.h"
 #include "qemu-options.h"
+#include "qemu-thread.h"
 #ifdef CONFIG_VIRTFS
 #include "fsdev/qemu-fsdev.h"
 #endif
@@ -2922,6 +2923,8 @@ int main(int argc, char **argv, char **envp)
             exit(1);
     }
 
+    threadlet_init();
+
     /* init generic devices */
     if (qemu_opts_foreach(qemu_find_opts("device"), device_init_func, NULL, 1) != 0)
         exit(1);