From: Ian Jackson <ian.jackson@eu.citrix.com>
Date: Wed, 7 Oct 2009 14:36:19 +0000 (+0100)
Subject: Refactor aio callback allocation to use an aiocb pool (Avi Kivity)
X-Git-Tag: xen-3.4.3-rc5-broken~44
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=efb4162ee6ad7ea15d1589eb09409854379f5139;p=qemu-xen-3.4-testing.git

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

[ Backported from 6bbff9a0b495918309074ac60375be5f9dc868b3
  by Stefano Stabellini. ]

Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
---

diff --git a/block.c b/block.c
index 36f5eb91..c26d4aa6 100644
--- a/block.c
+++ b/block.c
@@ -145,6 +145,7 @@ static void bdrv_register(BlockDriver *bdrv)
     }
     if (!bdrv->bdrv_aio_flush)
         bdrv->bdrv_aio_flush = bdrv_aio_flush_em;
+    aio_pool_init(&bdrv->aio_pool, bdrv->aiocb_size, bdrv->bdrv_aio_cancel);
     bdrv->next = first_drv;
     first_drv = bdrv;
 }
@@ -1479,14 +1480,12 @@ 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);
 }
 
 BlockDriverAIOCB *bdrv_aio_flush(BlockDriverState *bs, 
@@ -1633,18 +1632,25 @@ void bdrv_init(void)
 #endif
 }
 
-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;
@@ -1652,12 +1658,18 @@ 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 1c8655b2..6d2c2fc4 100644
--- a/block_int.h
+++ b/block_int.h
@@ -32,6 +32,12 @@
 
 #define BLOCK_DRIVER_FLAG_EXTENDABLE  0x0001u
 
+typedef struct AIOPool {
+    void (*cancel)(BlockDriverAIOCB *acb);
+    int aiocb_size;
+    BlockDriverAIOCB *free_aiocb;
+} AIOPool;
+
 struct BlockDriver {
     const char *format_name;
     int instance_size;
@@ -95,7 +101,7 @@ struct BlockDriver {
     int (*bdrv_ioctl)(BlockDriverState *bs, unsigned long int req, void *buf);
 
     unsigned bdrv_flags;
-    BlockDriverAIOCB *free_aiocb;
+    AIOPool aio_pool;
     struct BlockDriver *next;
 };
 
@@ -146,6 +152,7 @@ struct BlockDriverState {
 };
 
 struct BlockDriverAIOCB {
+    AIOPool *pool;
     BlockDriverState *bs;
     BlockDriverCompletionFunc *cb;
     void *opaque;
@@ -154,8 +161,13 @@ 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;