[Qemu-devel] [PATCH 02/12] Introduce work concept in posix-aio-compat.c

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

This patch introduces work concept by introducing the
ThreadletWork structure.

Signed-off-by: Arun R Bharadwaj <arun@linux.vnet.ibm.com>
Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
---
 posix-aio-compat.c |   20 ++++++++++++++------
 1 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/posix-aio-compat.c b/posix-aio-compat.c
index 82862ec..ddf42f5 100644
--- a/posix-aio-compat.c
+++ b/posix-aio-compat.c
@@ -33,6 +33,10 @@
 
 static QemuMutex aiocb_mutex;
 static QemuCond aiocb_completion;
+typedef struct ThreadletWork
+{
+    QTAILQ_ENTRY(ThreadletWork) node;
+} ThreadletWork;
 
 struct qemu_paiocb {
     BlockDriverAIOCB common;
@@ -47,13 +51,13 @@ struct qemu_paiocb {
     int ev_signo;
     off_t aio_offset;
 
-    QTAILQ_ENTRY(qemu_paiocb) node;
     int aio_type;
     ssize_t ret;
     int active;
     struct qemu_paiocb *next;
 
     int async_context_id;
+    ThreadletWork work;
 };
 
 typedef struct PosixAioState {
@@ -69,7 +73,7 @@ static pthread_attr_t attr;
 static int max_threads = 64;
 static int cur_threads = 0;
 static int idle_threads = 0;
-static QTAILQ_HEAD(, qemu_paiocb) request_list;
+static QTAILQ_HEAD(, ThreadletWork) request_list;
 
 #ifdef CONFIG_PREADV
 static int preadv_present = 1;
@@ -307,6 +311,7 @@ static ssize_t handle_aiocb_rw(struct qemu_paiocb *aiocb)
 static void *aio_thread(void *unused)
 {
     pid_t pid;
+    ThreadletWork *work;
 
     pid = getpid();
 
@@ -330,8 +335,11 @@ static void *aio_thread(void *unused)
         if (QTAILQ_EMPTY(&request_list))
             break;
 
-        aiocb = QTAILQ_FIRST(&request_list);
-        QTAILQ_REMOVE(&request_list, aiocb, node);
+        work = QTAILQ_FIRST(&request_list);
+        QTAILQ_REMOVE(&request_list, work, node);
+
+        aiocb = container_of(work, struct qemu_paiocb, work);
+
         aiocb->active = 1;
         idle_threads--;
         mutex_unlock(&lock);
@@ -398,7 +406,7 @@ static void qemu_paio_submit(struct qemu_paiocb *aiocb)
     mutex_lock(&lock);
     if (idle_threads == 0 && cur_threads < max_threads)
         spawn_thread();
-    QTAILQ_INSERT_TAIL(&request_list, aiocb, node);
+    QTAILQ_INSERT_TAIL(&request_list, &aiocb->work, node);
     mutex_unlock(&lock);
     cond_signal(&cond);
 }
@@ -548,7 +556,7 @@ static void paio_cancel(BlockDriverAIOCB *blockacb)
 
     qemu_mutex_lock(&aiocb_mutex);
     if (!acb->active) {
-        QTAILQ_REMOVE(&request_list, acb, node);
+        QTAILQ_REMOVE(&request_list, &acb->work, node);
         acb->ret = -ECANCELED;
     } else if (acb->ret == -EINPROGRESS) {
         active = 1;