[Qemu-devel] [STABLE][PATCH 2/4] Move block dma helpers aiocb to store dma state

[Mark McLoughlin <markmc@redhat.com>]

From: Avi Kivity <avi@redhat.com>

Use the dedicated dma aiocb to store intermediate state for dma block
transactions.

Signed-off-by: Avi Kivity <avi@redhat.com>

---
 dma-helpers.c |   37 ++++++++++++++++++++-----------------
 1 files changed, 20 insertions(+), 17 deletions(-)

diff --git a/dma-helpers.c b/dma-helpers.c
index 19fa4f0..96a120c 100644
--- a/dma-helpers.c
+++ b/dma-helpers.c
@@ -39,6 +39,7 @@ void qemu_sglist_destroy(QEMUSGList *qsg)
 }
 
 typedef struct {
+    BlockDriverAIOCB common;
     BlockDriverState *bs;
     BlockDriverAIOCB *acb;
     QEMUSGList *sg;
@@ -48,13 +49,13 @@ typedef struct {
     target_phys_addr_t sg_cur_byte;
     QEMUIOVector iov;
     QEMUBH *bh;
-} DMABlockState;
+} DMAAIOCB;
 
 static void dma_bdrv_cb(void *opaque, int ret);
 
 static void reschedule_dma(void *opaque)
 {
-    DMABlockState *dbs = (DMABlockState *)opaque;
+    DMAAIOCB *dbs = (DMAAIOCB *)opaque;
 
     qemu_bh_delete(dbs->bh);
     dbs->bh = NULL;
@@ -63,7 +64,7 @@ static void reschedule_dma(void *opaque)
 
 static void continue_after_map_failure(void *opaque)
 {
-    DMABlockState *dbs = (DMABlockState *)opaque;
+    DMAAIOCB *dbs = (DMAAIOCB *)opaque;
 
     dbs->bh = qemu_bh_new(reschedule_dma, dbs);
     qemu_bh_schedule(dbs->bh);
@@ -71,11 +72,12 @@ static void continue_after_map_failure(void *opaque)
 
 static void dma_bdrv_cb(void *opaque, int ret)
 {
-    DMABlockState *dbs = (DMABlockState *)opaque;
+    DMAAIOCB *dbs = (DMAAIOCB *)opaque;
     target_phys_addr_t cur_addr, cur_len;
     void *mem;
     int i;
 
+    dbs->acb = NULL;
     dbs->sector_num += dbs->iov.size / 512;
     for (i = 0; i < dbs->iov.niov; ++i) {
         cpu_physical_memory_unmap(dbs->iov.iov[i].iov_base,
@@ -85,10 +87,9 @@ static void dma_bdrv_cb(void *opaque, int ret)
     qemu_iovec_reset(&dbs->iov);
 
     if (dbs->sg_cur_index == dbs->sg->nsg || ret < 0) {
-        dbs->acb->cb(dbs->acb->opaque, ret);
+        dbs->common.cb(dbs->common.opaque, ret);
         qemu_iovec_destroy(&dbs->iov);
-        qemu_aio_release(dbs->acb);
-        qemu_free(dbs);
+        qemu_aio_release(dbs);
         return;
     }
 
@@ -112,11 +113,11 @@ static void dma_bdrv_cb(void *opaque, int ret)
     }
 
     if (dbs->is_write) {
-        bdrv_aio_writev(dbs->bs, dbs->sector_num, &dbs->iov,
-                        dbs->iov.size / 512, dma_bdrv_cb, dbs);
+        dbs->acb = bdrv_aio_writev(dbs->bs, dbs->sector_num, &dbs->iov,
+                                   dbs->iov.size / 512, dma_bdrv_cb, dbs);
     } else {
-        bdrv_aio_readv(dbs->bs, dbs->sector_num, &dbs->iov,
-                       dbs->iov.size / 512, dma_bdrv_cb, dbs);
+        dbs->acb = bdrv_aio_readv(dbs->bs, dbs->sector_num, &dbs->iov,
+                                  dbs->iov.size / 512, dma_bdrv_cb, dbs);
     }
 }
 
@@ -125,10 +126,10 @@ static BlockDriverAIOCB *dma_bdrv_io(
     BlockDriverCompletionFunc *cb, void *opaque,
     int is_write)
 {
-    DMABlockState *dbs = qemu_malloc(sizeof(*dbs));
+    DMAAIOCB *dbs =  qemu_aio_get_pool(&dma_aio_pool, bs, cb, opaque);
 
+    dbs->acb = NULL;
     dbs->bs = bs;
-    dbs->acb = qemu_aio_get_pool(&dma_aio_pool, bs, cb, opaque);
     dbs->sg = sg;
     dbs->sector_num = sector_num;
     dbs->sg_cur_index = 0;
@@ -137,7 +138,7 @@ static BlockDriverAIOCB *dma_bdrv_io(
     dbs->bh = NULL;
     qemu_iovec_init(&dbs->iov, sg->nsg);
     dma_bdrv_cb(dbs, 0);
-    return dbs->acb;
+    return &dbs->common;
 }
 
 
@@ -157,12 +158,14 @@ BlockDriverAIOCB *dma_bdrv_write(BlockDriverState *bs,
 
 static void dma_aio_cancel(BlockDriverAIOCB *acb)
 {
-    DMABlockState *dbs = (DMABlockState *)acb->opaque;
+    DMAAIOCB *dbs = container_of(acb, DMAAIOCB, common);
 
-    bdrv_aio_cancel(dbs->acb);
+    if (dbs->acb) {
+        bdrv_aio_cancel(dbs->acb);
+    }
 }
 
 void dma_helper_init(void)
 {
-    aio_pool_init(&dma_aio_pool, sizeof(BlockDriverAIOCB), dma_aio_cancel);
+    aio_pool_init(&dma_aio_pool, sizeof(DMAAIOCB), dma_aio_cancel);
 }
-- 
1.6.0.6