Refactor aio callback allocation to use an aiocb pool (Avi Kivity)

Move the AIOCB allocation code to use a dedicate structure, AIOPool.  AIOCB
specific information, such as the AIOCB size and cancellation routine, is
moved into the pool.

At present, there is exactly one pool per block format driver, maintaining
the status quo.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6870 c046a42c-6fe2-441c-8c8c-71466251a162

2 files changed, 40 insertions, 16 deletions

diff --git a/block.c b/block.c
index 3f262fa590..1aa3de573b 100644
--- a/block.c
+++ b/block.c
@@ -141,6 +141,7 @@ static void bdrv_register(BlockDriver *bdrv)
         bdrv->bdrv_read = bdrv_read_em;
         bdrv->bdrv_write = bdrv_write_em;
     }
+    aio_pool_init(&bdrv->aio_pool, bdrv->aiocb_size, bdrv->bdrv_aio_cancel);
     bdrv->next = first_drv;
     first_drv = bdrv;
 }
@@ -1443,14 +1444,12 @@ BlockDriverAIOCB *bdrv_aio_write(BlockDriverState *bs, int64_t sector_num,
 
 void bdrv_aio_cancel(BlockDriverAIOCB *acb)
 {
-    BlockDriver *drv = acb->bs->drv;
-
     if (acb->cb == bdrv_aio_rw_vector_cb) {
         VectorTranslationState *s = acb->opaque;
         acb = s->aiocb;
     }
 
-    drv->bdrv_aio_cancel(acb);
+    acb->pool->cancel(acb);
 }
 
 
@@ -1568,18 +1567,25 @@ void bdrv_init(void)
     bdrv_register(&bdrv_nbd);
 }
 
-void *qemu_aio_get(BlockDriverState *bs, BlockDriverCompletionFunc *cb,
-                   void *opaque)
+void aio_pool_init(AIOPool *pool, int aiocb_size,
+                   void (*cancel)(BlockDriverAIOCB *acb))
+{
+    pool->aiocb_size = aiocb_size;
+    pool->cancel = cancel;
+    pool->free_aiocb = NULL;
+}
+
+void *qemu_aio_get_pool(AIOPool *pool, BlockDriverState *bs,
+                        BlockDriverCompletionFunc *cb, void *opaque)
 {
-    BlockDriver *drv;
     BlockDriverAIOCB *acb;
 
-    drv = bs->drv;
-    if (drv->free_aiocb) {
-        acb = drv->free_aiocb;
-        drv->free_aiocb = acb->next;
+    if (pool->free_aiocb) {
+        acb = pool->free_aiocb;
+        pool->free_aiocb = acb->next;
     } else {
-        acb = qemu_mallocz(drv->aiocb_size);
+        acb = qemu_mallocz(pool->aiocb_size);
+        acb->pool = pool;
     }
     acb->bs = bs;
     acb->cb = cb;
@@ -1587,12 +1593,18 @@ void *qemu_aio_get(BlockDriverState *bs, BlockDriverCompletionFunc *cb,
     return acb;
 }
 
+void *qemu_aio_get(BlockDriverState *bs, BlockDriverCompletionFunc *cb,
+                   void *opaque)
+{
+    return qemu_aio_get_pool(&bs->drv->aio_pool, bs, cb, opaque);
+}
+
 void qemu_aio_release(void *p)
 {
-    BlockDriverAIOCB *acb = p;
-    BlockDriver *drv = acb->bs->drv;
-    acb->next = drv->free_aiocb;
-    drv->free_aiocb = acb;
+    BlockDriverAIOCB *acb = (BlockDriverAIOCB *)p;
+    AIOPool *pool = acb->pool;
+    acb->next = pool->free_aiocb;
+    pool->free_aiocb = acb;
 }
 
 /**************************************************************/
diff --git a/block_int.h b/block_int.h
index c6af1c64da..e58163773a 100644
--- a/block_int.h
+++ b/block_int.h
@@ -30,6 +30,12 @@
 #define BLOCK_FLAG_COMPRESS	2
 #define BLOCK_FLAG_COMPAT6	4
 
+typedef struct AIOPool {
+    void (*cancel)(BlockDriverAIOCB *acb);
+    int aiocb_size;
+    BlockDriverAIOCB *free_aiocb;
+} AIOPool;
+
 struct BlockDriver {
     const char *format_name;
     int instance_size;
@@ -90,7 +96,7 @@ struct BlockDriver {
     /* to control generic scsi devices */
     int (*bdrv_ioctl)(BlockDriverState *bs, unsigned long int req, void *buf);
 
-    BlockDriverAIOCB *free_aiocb;
+    AIOPool aio_pool;
     struct BlockDriver *next;
 };
 
@@ -140,6 +146,7 @@ struct BlockDriverState {
 };
 
 struct BlockDriverAIOCB {
+    AIOPool *pool;
     BlockDriverState *bs;
     BlockDriverCompletionFunc *cb;
     void *opaque;
@@ -148,8 +155,13 @@ struct BlockDriverAIOCB {
 
 void get_tmp_filename(char *filename, int size);
 
+void aio_pool_init(AIOPool *pool, int aiocb_size,
+                   void (*cancel)(BlockDriverAIOCB *acb));
+
 void *qemu_aio_get(BlockDriverState *bs, BlockDriverCompletionFunc *cb,
                    void *opaque);
+void *qemu_aio_get_pool(AIOPool *pool, BlockDriverState *bs,
+                        BlockDriverCompletionFunc *cb, void *opaque);
 void qemu_aio_release(void *p);
 
 extern BlockDriverState *bdrv_first;