[Qemu-devel] [PATCH v6 2/4] block: add the block queue support

[Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>]

Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
---
 Makefile.objs     |    2 +-
 block/blk-queue.c |  226 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 block/blk-queue.h |   63 +++++++++++++++
 3 files changed, 290 insertions(+), 1 deletions(-)
 create mode 100644 block/blk-queue.c
 create mode 100644 block/blk-queue.h

diff --git a/Makefile.objs b/Makefile.objs
index d1f3e5d..96a7323 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -33,7 +33,7 @@ block-nested-y += raw.o cow.o qcow.o vdi.o vmdk.o cloop.o dmg.o bochs.o vpc.o vv
 block-nested-y += qcow2.o qcow2-refcount.o qcow2-cluster.o qcow2-snapshot.o qcow2-cache.o
 block-nested-y += qed.o qed-gencb.o qed-l2-cache.o qed-table.o qed-cluster.o
 block-nested-y += qed-check.o
-block-nested-y += parallels.o nbd.o blkdebug.o sheepdog.o blkverify.o
+block-nested-y += parallels.o nbd.o blkdebug.o sheepdog.o blkverify.o blk-queue.o
 block-nested-$(CONFIG_WIN32) += raw-win32.o
 block-nested-$(CONFIG_POSIX) += raw-posix.o
 block-nested-$(CONFIG_CURL) += curl.o
diff --git a/block/blk-queue.c b/block/blk-queue.c
new file mode 100644
index 0000000..eac824c
--- /dev/null
+++ b/block/blk-queue.c
@@ -0,0 +1,226 @@
+/*
+ * QEMU System Emulator queue definition for block layer
+ *
+ * Copyright (c) IBM, Corp. 2011
+ *
+ * Authors:
+ *  Zhi Yong Wu  <zwu.kernel@gmail.com>
+ *  Stefan Hajnoczi <stefanha@gmail.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "block_int.h"
+#include "block/blk-queue.h"
+#include "qemu-common.h"
+
+/* The APIs for block request queue on qemu block layer.
+ */
+
+struct BlockIORequest {
+    QTAILQ_ENTRY(BlockIORequest) entry;
+    BlockDriverState *bs;
+    BlockRequestHandler *handler;
+    int64_t sector_num;
+    QEMUIOVector *qiov;
+    int nb_sectors;
+    BlockDriverCompletionFunc *cb;
+    void *opaque;
+    BlockDriverAIOCB *acb;
+};
+
+struct BlockQueue {
+    QTAILQ_HEAD(requests, BlockIORequest) requests;
+    BlockIORequest *request;
+    bool flushing;
+};
+
+struct BlockQueueAIOCB {
+    BlockDriverAIOCB common;
+    BlockDriverCompletionFunc *real_cb;
+    BlockDriverAIOCB *real_acb;
+    void *opaque;
+    BlockIORequest *request;
+};
+
+static void qemu_block_queue_dequeue(BlockQueue *queue, BlockIORequest *request)
+{
+    BlockIORequest *req;
+
+    while (!QTAILQ_EMPTY(&queue->requests)) {
+        req = QTAILQ_FIRST(&queue->requests);
+        if (req == request) {
+            QTAILQ_REMOVE(&queue->requests, req, entry);
+            break;
+        }
+    }
+}
+
+static void qemu_block_queue_cancel(BlockDriverAIOCB *acb)
+{
+    BlockQueueAIOCB *blkacb = container_of(acb, BlockQueueAIOCB, common);
+    if (blkacb->real_acb) {
+        bdrv_aio_cancel(blkacb->real_acb);
+    } else {
+        assert(blkacb->common.bs->block_queue);
+        qemu_block_queue_dequeue(blkacb->common.bs->block_queue,
+                                 blkacb->request);
+    }
+
+    qemu_aio_release(blkacb);
+}
+
+static AIOPool block_queue_pool = {
+    .aiocb_size         = sizeof(struct BlockQueueAIOCB),
+    .cancel             = qemu_block_queue_cancel,
+};
+
+static void qemu_block_queue_callback(void *opaque, int ret)
+{
+    BlockQueueAIOCB *acb = opaque;
+
+    if (acb->real_cb) {
+        acb->real_cb(acb->opaque, ret);
+    }
+
+    qemu_aio_release(acb);
+}
+
+BlockQueue *qemu_new_block_queue(void)
+{
+    BlockQueue *queue;
+
+    queue = g_malloc0(sizeof(BlockQueue));
+
+    QTAILQ_INIT(&queue->requests);
+
+    queue->flushing = false;
+    queue->request  = NULL;
+
+    return queue;
+}
+
+void qemu_del_block_queue(BlockQueue *queue)
+{
+    BlockIORequest *request, *next;
+
+    QTAILQ_FOREACH_SAFE(request, &queue->requests, entry, next) {
+        QTAILQ_REMOVE(&queue->requests, request, entry);
+        g_free(request);
+    }
+
+    g_free(queue);
+}
+
+BlockDriverAIOCB *qemu_block_queue_enqueue(BlockQueue *queue,
+                        BlockDriverState *bs,
+                        BlockRequestHandler *handler,
+                        int64_t sector_num,
+                        QEMUIOVector *qiov,
+                        int nb_sectors,
+                        BlockDriverCompletionFunc *cb,
+                        void *opaque)
+{
+    BlockIORequest *request;
+    BlockDriverAIOCB *acb;
+    BlockQueueAIOCB *blkacb;
+
+    if (queue->request) {
+        request             = queue->request;
+        assert(request->acb);
+        acb                 = request->acb;
+        QTAILQ_INSERT_TAIL(&queue->requests, request, entry);
+        queue->request      = NULL;
+    } else {
+        request             = g_malloc0(sizeof(BlockIORequest));
+        request->bs         = bs;
+        request->handler    = handler;
+        request->sector_num = sector_num;
+        request->qiov       = qiov;
+        request->nb_sectors = nb_sectors;
+        request->cb         = qemu_block_queue_callback;
+        QTAILQ_INSERT_TAIL(&queue->requests, request, entry);
+
+        acb = qemu_aio_get(&block_queue_pool, bs,
+                           qemu_block_queue_callback, opaque);
+        blkacb = container_of(acb, BlockQueueAIOCB, common);
+        blkacb->real_cb     = cb;
+        blkacb->real_acb    = NULL;
+        blkacb->opaque      = opaque;
+        blkacb->request     = request;
+
+        request->acb        = acb;
+        request->opaque = (void *)blkacb;
+    }
+
+    return acb;
+}
+
+static int qemu_block_queue_handler(BlockIORequest *request)
+{
+    int ret;
+    BlockDriverAIOCB *res;
+
+    res = request->handler(request->bs, request->sector_num,
+                           request->qiov, request->nb_sectors,
+                           request->cb, request->opaque);
+    if (res) {
+        BlockQueueAIOCB *blkacb =
+                container_of(request->acb, BlockQueueAIOCB, common);
+        blkacb->real_acb = res;
+    }
+
+    ret = (res == NULL) ? 0 : 1;
+
+    return ret;
+}
+
+void qemu_block_queue_flush(BlockQueue *queue)
+{
+    queue->flushing = true;
+    while (!QTAILQ_EMPTY(&queue->requests)) {
+        BlockIORequest *request = NULL;
+        int ret = 0;
+
+        request = QTAILQ_FIRST(&queue->requests);
+        QTAILQ_REMOVE(&queue->requests, request, entry);
+
+        queue->request = request;
+        ret = qemu_block_queue_handler(request);
+
+        if (ret == 0) {
+            QTAILQ_INSERT_HEAD(&queue->requests, request, entry);
+            queue->request = NULL;
+            break;
+        }
+
+        if (queue->request) {
+            g_free(request);
+        }
+
+        queue->request = NULL;
+    }
+
+    queue->flushing = false;
+}
+
+bool qemu_block_queue_has_pending(BlockQueue *queue)
+{
+    return !queue->flushing && !QTAILQ_EMPTY(&queue->requests);
+}
diff --git a/block/blk-queue.h b/block/blk-queue.h
new file mode 100644
index 0000000..84c2407
--- /dev/null
+++ b/block/blk-queue.h
@@ -0,0 +1,63 @@
+/*
+ * QEMU System Emulator queue declaration for block layer
+ *
+ * Copyright (c) IBM, Corp. 2011
+ *
+ * Authors:
+ *  Zhi Yong Wu  <zwu.kernel@gmail.com>
+ *  Stefan Hajnoczi <stefanha@gmail.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef QEMU_BLOCK_QUEUE_H
+#define QEMU_BLOCK_QUEUE_H
+
+#include "block.h"
+#include "qemu-queue.h"
+
+typedef BlockDriverAIOCB* (BlockRequestHandler) (BlockDriverState *bs,
+                                int64_t sector_num, QEMUIOVector *qiov,
+                                int nb_sectors, BlockDriverCompletionFunc *cb,
+                                void *opaque);
+
+typedef struct BlockIORequest BlockIORequest;
+
+typedef struct BlockQueue BlockQueue;
+
+typedef struct BlockQueueAIOCB BlockQueueAIOCB;
+
+BlockQueue *qemu_new_block_queue(void);
+
+void qemu_del_block_queue(BlockQueue *queue);
+
+BlockDriverAIOCB *qemu_block_queue_enqueue(BlockQueue *queue,
+                        BlockDriverState *bs,
+                        BlockRequestHandler *handler,
+                        int64_t sector_num,
+                        QEMUIOVector *qiov,
+                        int nb_sectors,
+                        BlockDriverCompletionFunc *cb,
+                        void *opaque);
+
+void qemu_block_queue_flush(BlockQueue *queue);
+
+bool qemu_block_queue_has_pending(BlockQueue *queue);
+
+#endif /* QEMU_BLOCK_QUEUE_H */
-- 
1.7.6