[2/4] dma-helpers: change BlockBackend to opaque value in DMAIOFunc

Commit Message

Paolo Bonzini May 11, 2016, 11:41 a.m. UTC

Callers of dma_blk_io have no way to pass extra data to the DMAIOFunc,
because the original callback and opaque are gone by the time DMAIOFunc
is called.  On the other hand, the BlockBackend is usually derived
from those extra data that you could pass to the DMAIOFunc (in the
next patch, that would be the SCSIRequest).

So change DMAIOFunc's prototype, decoupling it from blk_aio_readv
and blk_aio_writev's.  The new prototype loses the BlockBackend
and gains an extra opaque value which, in the case of dma_blk_readv
and dma_blk_writev, is of course used for the BlockBackend.

Signed-off-by: Paolo Bonzini <[e-mail]>
---
 dma-helpers.c        | 51 ++++++++++++++++++++++++++++++++++++++-------------
 hw/ide/core.c        | 12 +++++++-----
 hw/ide/internal.h    |  4 ++--
 hw/ide/macio.c       |  4 ++--
 include/sysemu/dma.h | 11 ++++++-----
 5 files changed, 55 insertions(+), 27 deletions(-)

Comments

Fam Zheng May 17, 2016, 2:40 a.m. UTC | #1

On Wed, 05/11 13:41, Paolo Bonzini wrote:
> diff --git a/include/sysemu/dma.h b/include/sysemu/dma.h
> index b0fbb9b..ddc4afc 100644
> --- a/include/sysemu/dma.h
> +++ b/include/sysemu/dma.h
> @@ -197,14 +197,15 @@ void qemu_sglist_add(QEMUSGList *qsg, dma_addr_t base, dma_addr_t len);
>  void qemu_sglist_destroy(QEMUSGList *qsg);
>  #endif
>  
> -typedef BlockAIOCB *DMAIOFunc(BlockBackend *blk, int64_t sector_num,
> +typedef BlockAIOCB *DMAIOFunc(int64_t sector_num,
>                                QEMUIOVector *iov, int nb_sectors,
> -                              BlockCompletionFunc *cb, void *opaque);
> +                              BlockCompletionFunc *cb, void *cb_opaque,
> +                              void *opaque);
>  

The patch itself looks good, but I'm wondering if it's time to introduce:

    typedef struct {
        BlockCompletionFunc *cb;
        void *opaque;
    } BlockCompletion;

for more readability in such cases.

Fam

Patch

diff --git a/dma-helpers.c b/dma-helpers.c
index 4ad0bca..000620e 100644
--- a/dma-helpers.c
+++ b/dma-helpers.c
@@ -70,7 +70,7 @@  void qemu_sglist_destroy(QEMUSGList *qsg)
 
 typedef struct {
     BlockAIOCB common;
-    BlockBackend *blk;
+    AioContext *ctx;
     BlockAIOCB *acb;
     QEMUSGList *sg;
     uint64_t sector_num;
@@ -80,6 +80,7 @@  typedef struct {
     QEMUIOVector iov;
     QEMUBH *bh;
     DMAIOFunc *io_func;
+    void *io_func_opaque;
 } DMAAIOCB;
 
 static void dma_blk_cb(void *opaque, int ret);
@@ -154,8 +155,7 @@  static void dma_blk_cb(void *opaque, int ret)
 
     if (dbs->iov.size == 0) {
         trace_dma_map_wait(dbs);
-        dbs->bh = aio_bh_new(blk_get_aio_context(dbs->blk),
-                             reschedule_dma, dbs);
+        dbs->bh = aio_bh_new(dbs->ctx, reschedule_dma, dbs);
         cpu_register_map_client(dbs->bh);
         return;
     }
@@ -164,8 +164,9 @@  static void dma_blk_cb(void *opaque, int ret)
         qemu_iovec_discard_back(&dbs->iov, dbs->iov.size & ~BDRV_SECTOR_MASK);
     }
 
-    dbs->acb = dbs->io_func(dbs->blk, dbs->sector_num, &dbs->iov,
-                            dbs->iov.size / 512, dma_blk_cb, dbs);
+    dbs->acb = dbs->io_func(dbs->sector_num, &dbs->iov,
+                            dbs->iov.size / 512, dma_blk_cb, dbs,
+                            dbs->io_func_opaque);
     assert(dbs->acb);
 }
 
@@ -191,23 +192,25 @@  static const AIOCBInfo dma_aiocb_info = {
     .cancel_async       = dma_aio_cancel,
 };
 
-BlockAIOCB *dma_blk_io(
-    BlockBackend *blk, QEMUSGList *sg, uint64_t sector_num,
-    DMAIOFunc *io_func, BlockCompletionFunc *cb,
+BlockAIOCB *dma_blk_io(AioContext *ctx,
+    QEMUSGList *sg, uint64_t sector_num,
+    DMAIOFunc *io_func, void *io_func_opaque,
+    BlockCompletionFunc *cb,
     void *opaque, DMADirection dir)
 {
-    DMAAIOCB *dbs = blk_aio_get(&dma_aiocb_info, blk, cb, opaque);
+    DMAAIOCB *dbs = qemu_aio_get(&dma_aiocb_info, NULL, cb, opaque);
 
-    trace_dma_blk_io(dbs, blk, sector_num, (dir == DMA_DIRECTION_TO_DEVICE));
+    trace_dma_blk_io(dbs, io_func_opaque, sector_num, (dir == DMA_DIRECTION_TO_DEVICE));
 
     dbs->acb = NULL;
-    dbs->blk = blk;
     dbs->sg = sg;
+    dbs->ctx = ctx;
     dbs->sector_num = sector_num;
     dbs->sg_cur_index = 0;
     dbs->sg_cur_byte = 0;
     dbs->dir = dir;
     dbs->io_func = io_func;
+    dbs->io_func_opaque = io_func_opaque;
     dbs->bh = NULL;
     qemu_iovec_init(&dbs->iov, sg->nsg);
     dma_blk_cb(dbs, 0);
@@ -215,19 +218,41 @@  BlockAIOCB *dma_blk_io(
 }
 
 
+static
+BlockAIOCB *dma_blk_read_io_func(int64_t sector_num,
+                                 QEMUIOVector *iov, int nb_sectors,
+                                 BlockCompletionFunc *cb, void *cb_opaque,
+                                 void *opaque)
+{
+    BlockBackend *blk = opaque;
+    return blk_aio_readv(blk, sector_num, iov, nb_sectors, cb, cb_opaque);
+}
+
 BlockAIOCB *dma_blk_read(BlockBackend *blk,
                          QEMUSGList *sg, uint64_t sector,
                          void (*cb)(void *opaque, int ret), void *opaque)
 {
-    return dma_blk_io(blk, sg, sector, blk_aio_readv, cb, opaque,
+    return dma_blk_io(blk_get_aio_context(blk),
+                      sg, sector, dma_blk_read_io_func, blk, cb, opaque,
                       DMA_DIRECTION_FROM_DEVICE);
 }
 
+static
+BlockAIOCB *dma_blk_write_io_func(int64_t sector_num,
+                                  QEMUIOVector *iov, int nb_sectors,
+                                  BlockCompletionFunc *cb, void *cb_opaque,
+                                  void *opaque)
+{
+    BlockBackend *blk = opaque;
+    return blk_aio_writev(blk, sector_num, iov, nb_sectors, cb, cb_opaque);
+}
+
 BlockAIOCB *dma_blk_write(BlockBackend *blk,
                           QEMUSGList *sg, uint64_t sector,
                           void (*cb)(void *opaque, int ret), void *opaque)
 {
-    return dma_blk_io(blk, sg, sector, blk_aio_writev, cb, opaque,
+    return dma_blk_io(blk_get_aio_context(blk),
+                      sg, sector, dma_blk_write_io_func, blk, cb, opaque,
                       DMA_DIRECTION_TO_DEVICE);
 }
 
diff --git a/hw/ide/core.c b/hw/ide/core.c
index 41e6a2d..4057924 100644
--- a/hw/ide/core.c
+++ b/hw/ide/core.c
@@ -441,13 +441,14 @@  static void ide_issue_trim_cb(void *opaque, int ret)
     }
 }
 
-BlockAIOCB *ide_issue_trim(BlockBackend *blk,
+BlockAIOCB *ide_issue_trim(
         int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
-        BlockCompletionFunc *cb, void *opaque)
+        BlockCompletionFunc *cb, void *cb_opaque, void *opaque)
 {
+    BlockBackend *blk = opaque;
     TrimAIOCB *iocb;
 
-    iocb = blk_aio_get(&trim_aiocb_info, blk, cb, opaque);
+    iocb = blk_aio_get(&trim_aiocb_info, blk, cb, cb_opaque);
     iocb->blk = blk;
     iocb->bh = qemu_bh_new(ide_trim_bh_cb, iocb);
     iocb->ret = 0;
@@ -869,8 +870,9 @@  static void ide_dma_cb(void *opaque, int ret)
                                            ide_dma_cb, s);
         break;
     case IDE_DMA_TRIM:
-        s->bus->dma->aiocb = dma_blk_io(s->blk, &s->sg, sector_num,
-                                        ide_issue_trim, ide_dma_cb, s,
+        s->bus->dma->aiocb = dma_blk_io(blk_get_aio_context(s->blk),
+                                        &s->sg, sector_num,
+                                        ide_issue_trim, s->blk, ide_dma_cb, s,
                                         DMA_DIRECTION_TO_DEVICE);
         break;
     default:
diff --git a/hw/ide/internal.h b/hw/ide/internal.h
index d2c458f..1a3f3e8 100644
--- a/hw/ide/internal.h
+++ b/hw/ide/internal.h
@@ -613,9 +613,9 @@  void ide_transfer_start(IDEState *s, uint8_t *buf, int size,
                         EndTransferFunc *end_transfer_func);
 void ide_transfer_stop(IDEState *s);
 void ide_set_inactive(IDEState *s, bool more);
-BlockAIOCB *ide_issue_trim(BlockBackend *blk,
+BlockAIOCB *ide_issue_trim(
         int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
-        BlockCompletionFunc *cb, void *opaque);
+        BlockCompletionFunc *cb, void *cb_opaque, void *opaque);
 BlockAIOCB *ide_buffered_readv(IDEState *s, int64_t sector_num,
                                QEMUIOVector *iov, int nb_sectors,
                                BlockCompletionFunc *cb, void *opaque);
diff --git a/hw/ide/macio.c b/hw/ide/macio.c
index 76256eb..9773923 100644
--- a/hw/ide/macio.c
+++ b/hw/ide/macio.c
@@ -232,8 +232,8 @@  static void pmac_dma_trim(BlockBackend *blk,
     s->io_buffer_index += io->len;
     io->len = 0;
 
-    s->bus->dma->aiocb = ide_issue_trim(blk, (offset >> 9), &io->iov,
-                             (bytes >> 9), cb, io);
+    s->bus->dma->aiocb = ide_issue_trim((offset >> 9), &io->iov,
+                             (bytes >> 9), cb, io, blk);
 }
 
 static void pmac_ide_atapi_transfer_cb(void *opaque, int ret)
diff --git a/include/sysemu/dma.h b/include/sysemu/dma.h
index b0fbb9b..ddc4afc 100644
--- a/include/sysemu/dma.h
+++ b/include/sysemu/dma.h
@@ -197,14 +197,15 @@  void qemu_sglist_add(QEMUSGList *qsg, dma_addr_t base, dma_addr_t len);
 void qemu_sglist_destroy(QEMUSGList *qsg);
 #endif
 
-typedef BlockAIOCB *DMAIOFunc(BlockBackend *blk, int64_t sector_num,
+typedef BlockAIOCB *DMAIOFunc(int64_t sector_num,
                               QEMUIOVector *iov, int nb_sectors,
-                              BlockCompletionFunc *cb, void *opaque);
+                              BlockCompletionFunc *cb, void *cb_opaque,
+                              void *opaque);
 
-BlockAIOCB *dma_blk_io(BlockBackend *blk,
+BlockAIOCB *dma_blk_io(AioContext *ctx,
                        QEMUSGList *sg, uint64_t sector_num,
-                       DMAIOFunc *io_func, BlockCompletionFunc *cb,
-                       void *opaque, DMADirection dir);
+                       DMAIOFunc *io_func, void *io_func_opaque,
+                       BlockCompletionFunc *cb, void *opaque, DMADirection dir);
 BlockAIOCB *dma_blk_read(BlockBackend *blk,
                          QEMUSGList *sg, uint64_t sector,
                          BlockCompletionFunc *cb, void *opaque);