Re: [Qemu-devel] [PATCH 4/6] block: switch bdrv_aio_readv() to coroutines

[Kevin Wolf]

Am 05.10.2011 18:17, schrieb Stefan Hajnoczi:
 More sync, aio, and coroutine unification.  Make bdrv_aio_readv() go
 through coroutine request processing.
 
 Signed-off-by: Stefan Hajnoczi stefa...@linux.vnet.ibm.com
 ---
  block.c |   48 +++-
  1 files changed, 35 insertions(+), 13 deletions(-)
 
 diff --git a/block.c b/block.c
 index 90c29db..b83e911 100644
 --- a/block.c
 +++ b/block.c
 @@ -78,6 +78,15 @@ static int coroutine_fn bdrv_co_do_readv(BlockDriverState 
 *bs,
  int64_t sector_num, int nb_sectors, QEMUIOVector *qiov);
  static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs,
  int64_t sector_num, int nb_sectors, QEMUIOVector *qiov);
 +static BlockDriverAIOCB *bdrv_co_aio_rw_vector(BlockDriverState *bs,
 +   int64_t sector_num,
 +   QEMUIOVector *qiov,
 +   int nb_sectors,
 +   BlockDriverCompletionFunc *cb,
 +   void *opaque,
 +   bool is_write,
 +   CoroutineEntry *entry);
 +static void coroutine_fn bdrv_co_do_rw(void *opaque);
  
  static QTAILQ_HEAD(, BlockDriverState) bdrv_states =
  QTAILQ_HEAD_INITIALIZER(bdrv_states);
 @@ -2346,17 +2355,10 @@ BlockDriverAIOCB *bdrv_aio_readv(BlockDriverState 
 *bs, int64_t sector_num,
   QEMUIOVector *qiov, int nb_sectors,
   BlockDriverCompletionFunc *cb, void *opaque)
  {
 -BlockDriver *drv = bs-drv;
 -
  trace_bdrv_aio_readv(bs, sector_num, nb_sectors, opaque);
  
 -if (!drv)
 -return NULL;
 -if (bdrv_check_request(bs, sector_num, nb_sectors))
 -return NULL;
 -
 -return drv-bdrv_aio_readv(bs, sector_num, qiov, nb_sectors,
 -   cb, opaque);
 +return bdrv_co_aio_rw_vector(bs, sector_num, qiov, nb_sectors,
 + cb, opaque, false, bdrv_co_do_rw);
  }
  
  typedef struct BlockCompleteData {
 @@ -2803,6 +2805,7 @@ static void bdrv_co_rw_bh(void *opaque)
  qemu_aio_release(acb);
  }
  
 +/* Invoke .bdrv_co_readv/.bdrv_co_writev */
  static void coroutine_fn bdrv_co_rw(void *opaque)
  {
  BlockDriverAIOCBCoroutine *acb = opaque;
 @@ -2820,13 +2823,32 @@ static void coroutine_fn bdrv_co_rw(void *opaque)
  qemu_bh_schedule(acb-bh);
  }
  
 +/* Invoke bdrv_co_do_readv/bdrv_co_do_writev */
 +static void coroutine_fn bdrv_co_do_rw(void *opaque)
 +{
 +BlockDriverAIOCBCoroutine *acb = opaque;
 +BlockDriverState *bs = acb-common.bs;
 +
 +if (!acb-is_write) {
 +acb-req.error = bdrv_co_do_readv(bs, acb-req.sector,
 +acb-req.nb_sectors, acb-req.qiov);
 +} else {
 +acb-req.error = bdrv_co_do_writev(bs, acb-req.sector,
 +acb-req.nb_sectors, acb-req.qiov);
 +}
 +
 +acb-bh = qemu_bh_new(bdrv_co_rw_bh, acb);
 +qemu_bh_schedule(acb-bh);
 +}

The difference between the existing bdrv_co_rw and the new bdrv_co_do_rw
is that the former directly calls drv-... whereas the latter does some
checks first.

I think you could just switch bdrv_co_rw to do the checks. If I'm not
mistaken, the other path is dead code anyway after this change.
Actually, it looks like this series leaves quite a bit of dead code
behind, but I need to apply all patches and check the result to be sure.

Kevin

[Qemu-devel] [PATCH 4/6] block: switch bdrv_aio_readv() to coroutines

[Stefan Hajnoczi]

More sync, aio, and coroutine unification.  Make bdrv_aio_readv() go
through coroutine request processing.

Signed-off-by: Stefan Hajnoczi stefa...@linux.vnet.ibm.com
---
 block.c |   48 +++-
 1 files changed, 35 insertions(+), 13 deletions(-)

diff --git a/block.c b/block.c
index 90c29db..b83e911 100644
--- a/block.c
+++ b/block.c
@@ -78,6 +78,15 @@ static int coroutine_fn bdrv_co_do_readv(BlockDriverState 
*bs,
 int64_t sector_num, int nb_sectors, QEMUIOVector *qiov);
 static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs,
 int64_t sector_num, int nb_sectors, QEMUIOVector *qiov);
+static BlockDriverAIOCB *bdrv_co_aio_rw_vector(BlockDriverState *bs,
+   int64_t sector_num,
+   QEMUIOVector *qiov,
+   int nb_sectors,
+   BlockDriverCompletionFunc *cb,
+   void *opaque,
+   bool is_write,
+   CoroutineEntry *entry);
+static void coroutine_fn bdrv_co_do_rw(void *opaque);
 
 static QTAILQ_HEAD(, BlockDriverState) bdrv_states =
 QTAILQ_HEAD_INITIALIZER(bdrv_states);
@@ -2346,17 +2355,10 @@ BlockDriverAIOCB *bdrv_aio_readv(BlockDriverState *bs, 
int64_t sector_num,
  QEMUIOVector *qiov, int nb_sectors,
  BlockDriverCompletionFunc *cb, void *opaque)
 {
-BlockDriver *drv = bs-drv;
-
 trace_bdrv_aio_readv(bs, sector_num, nb_sectors, opaque);
 
-if (!drv)
-return NULL;
-if (bdrv_check_request(bs, sector_num, nb_sectors))
-return NULL;
-
-return drv-bdrv_aio_readv(bs, sector_num, qiov, nb_sectors,
-   cb, opaque);
+return bdrv_co_aio_rw_vector(bs, sector_num, qiov, nb_sectors,
+ cb, opaque, false, bdrv_co_do_rw);
 }
 
 typedef struct BlockCompleteData {
@@ -2803,6 +2805,7 @@ static void bdrv_co_rw_bh(void *opaque)
 qemu_aio_release(acb);
 }
 
+/* Invoke .bdrv_co_readv/.bdrv_co_writev */
 static void coroutine_fn bdrv_co_rw(void *opaque)
 {
 BlockDriverAIOCBCoroutine *acb = opaque;
@@ -2820,13 +2823,32 @@ static void coroutine_fn bdrv_co_rw(void *opaque)
 qemu_bh_schedule(acb-bh);
 }
 
+/* Invoke bdrv_co_do_readv/bdrv_co_do_writev */
+static void coroutine_fn bdrv_co_do_rw(void *opaque)
+{
+BlockDriverAIOCBCoroutine *acb = opaque;
+BlockDriverState *bs = acb-common.bs;
+
+if (!acb-is_write) {
+acb-req.error = bdrv_co_do_readv(bs, acb-req.sector,
+acb-req.nb_sectors, acb-req.qiov);
+} else {
+acb-req.error = bdrv_co_do_writev(bs, acb-req.sector,
+acb-req.nb_sectors, acb-req.qiov);
+}
+
+acb-bh = qemu_bh_new(bdrv_co_rw_bh, acb);
+qemu_bh_schedule(acb-bh);
+}
+
 static BlockDriverAIOCB *bdrv_co_aio_rw_vector(BlockDriverState *bs,
int64_t sector_num,
QEMUIOVector *qiov,
int nb_sectors,
BlockDriverCompletionFunc *cb,
void *opaque,
-   bool is_write)
+   bool is_write,
+   CoroutineEntry *entry)
 {
 Coroutine *co;
 BlockDriverAIOCBCoroutine *acb;
@@ -2837,7 +2859,7 @@ static BlockDriverAIOCB 
*bdrv_co_aio_rw_vector(BlockDriverState *bs,
 acb-req.qiov = qiov;
 acb-is_write = is_write;
 
-co = qemu_coroutine_create(bdrv_co_rw);
+co = qemu_coroutine_create(entry);
 qemu_coroutine_enter(co, acb);
 
 return acb-common;
@@ -2848,7 +2870,7 @@ static BlockDriverAIOCB 
*bdrv_co_aio_readv_em(BlockDriverState *bs,
 BlockDriverCompletionFunc *cb, void *opaque)
 {
 return bdrv_co_aio_rw_vector(bs, sector_num, qiov, nb_sectors, cb, opaque,
- false);
+ false, bdrv_co_rw);
 }
 
 static BlockDriverAIOCB *bdrv_co_aio_writev_em(BlockDriverState *bs,
@@ -2856,7 +2878,7 @@ static BlockDriverAIOCB 
*bdrv_co_aio_writev_em(BlockDriverState *bs,
 BlockDriverCompletionFunc *cb, void *opaque)
 {
 return bdrv_co_aio_rw_vector(bs, sector_num, qiov, nb_sectors, cb, opaque,
- true);
+ true, bdrv_co_rw);
 }
 
 static BlockDriverAIOCB *bdrv_aio_flush_em(BlockDriverState *bs,
-- 
1.7.6.3