dma: use current AioContext for dma_blk_io()

In the past a single AioContext was used for block I/O and it was
fetched using blk_get_aio_context(). Nowadays the block layer supports
running I/O from any AioContext and multiple AioContexts at the same
time. Remove the dma_blk_io() AioContext argument and use the current
AioContext instead.

This makes calling the function easier and enables multiple IOThreads to
use dma_blk_io() concurrently for the same block device.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20250311132616.1049687-3-stefanha@redhat.com>
Tested-by: Peter Krempa <pkrempa@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

hw/ide/core.c

@@ -968,8 +968,7 @@ static void ide_dma_cb(void *opaque, int ret)
                                            BDRV_SECTOR_SIZE, ide_dma_cb, s);
         break;
     case IDE_DMA_TRIM:
-        s->bus->dma->aiocb = dma_blk_io(blk_get_aio_context(s->blk),
-                                        &s->sg, offset, BDRV_SECTOR_SIZE,
+        s->bus->dma->aiocb = dma_blk_io(&s->sg, offset, BDRV_SECTOR_SIZE,
                                         ide_issue_trim, s, ide_dma_cb, s,
                                         DMA_DIRECTION_TO_DEVICE);
         break;

hw/ide/macio.c

@@ -187,8 +187,7 @@ static void pmac_ide_transfer_cb(void *opaque, int ret)
                                            pmac_ide_transfer_cb, io);
         break;
     case IDE_DMA_TRIM:
-        s->bus->dma->aiocb = dma_blk_io(blk_get_aio_context(s->blk), &s->sg,
-                                        offset, 0x1, ide_issue_trim, s,
+        s->bus->dma->aiocb = dma_blk_io(&s->sg, offset, 0x1, ide_issue_trim, s,
                                         pmac_ide_transfer_cb, io,
                                         DMA_DIRECTION_TO_DEVICE);
         break;

hw/scsi/scsi-disk.c

@@ -487,8 +487,7 @@ static void scsi_do_read(SCSIDiskReq *r, int ret)
     if (r->req.sg) {
         dma_acct_start(s->qdev.conf.blk, &r->acct, r->req.sg, BLOCK_ACCT_READ);
         r->req.residual -= r->req.sg->size;
-        r->req.aiocb = dma_blk_io(blk_get_aio_context(s->qdev.conf.blk),
-                                  r->req.sg, r->sector << BDRV_SECTOR_BITS,
+        r->req.aiocb = dma_blk_io(r->req.sg, r->sector << BDRV_SECTOR_BITS,
                                   BDRV_SECTOR_SIZE,
                                   sdc->dma_readv, r, scsi_dma_complete, r,
                                   DMA_DIRECTION_FROM_DEVICE);
@@ -650,8 +649,7 @@ static void scsi_write_data(SCSIRequest *req)
     if (r->req.sg) {
         dma_acct_start(s->qdev.conf.blk, &r->acct, r->req.sg, BLOCK_ACCT_WRITE);
         r->req.residual -= r->req.sg->size;
-        r->req.aiocb = dma_blk_io(blk_get_aio_context(s->qdev.conf.blk),
-                                  r->req.sg, r->sector << BDRV_SECTOR_BITS,
+        r->req.aiocb = dma_blk_io(r->req.sg, r->sector << BDRV_SECTOR_BITS,
                                   BDRV_SECTOR_SIZE,
                                   sdc->dma_writev, r, scsi_dma_complete, r,
                                   DMA_DIRECTION_TO_DEVICE);

include/system/dma.h

@@ -290,8 +290,7 @@ typedef BlockAIOCB *DMAIOFunc(int64_t offset, QEMUIOVector *iov,
                               BlockCompletionFunc *cb, void *cb_opaque,
                               void *opaque);
 
-BlockAIOCB *dma_blk_io(AioContext *ctx,
-                       QEMUSGList *sg, uint64_t offset, uint32_t align,
+BlockAIOCB *dma_blk_io(QEMUSGList *sg, uint64_t offset, uint32_t align,
                        DMAIOFunc *io_func, void *io_func_opaque,
                        BlockCompletionFunc *cb, void *opaque, DMADirection dir);
 BlockAIOCB *dma_blk_read(BlockBackend *blk,

system/dma-helpers.c

@@ -211,7 +211,7 @@ static const AIOCBInfo dma_aiocb_info = {
     .cancel_async       = dma_aio_cancel,
 };
 
-BlockAIOCB *dma_blk_io(AioContext *ctx,
+BlockAIOCB *dma_blk_io(
     QEMUSGList *sg, uint64_t offset, uint32_t align,
     DMAIOFunc *io_func, void *io_func_opaque,
     BlockCompletionFunc *cb,
@@ -223,7 +223,7 @@ BlockAIOCB *dma_blk_io(AioContext *ctx,
 
     dbs->acb = NULL;
     dbs->sg = sg;
-    dbs->ctx = ctx;
+    dbs->ctx = qemu_get_current_aio_context();
     dbs->offset = offset;
     dbs->align = align;
     dbs->sg_cur_index = 0;
@@ -251,7 +251,7 @@ BlockAIOCB *dma_blk_read(BlockBackend *blk,
                          QEMUSGList *sg, uint64_t offset, uint32_t align,
                          void (*cb)(void *opaque, int ret), void *opaque)
 {
-    return dma_blk_io(blk_get_aio_context(blk), sg, offset, align,
+    return dma_blk_io(sg, offset, align,
                       dma_blk_read_io_func, blk, cb, opaque,
                       DMA_DIRECTION_FROM_DEVICE);
 }
@@ -269,7 +269,7 @@ BlockAIOCB *dma_blk_write(BlockBackend *blk,
                           QEMUSGList *sg, uint64_t offset, uint32_t align,
                           void (*cb)(void *opaque, int ret), void *opaque)
 {
-    return dma_blk_io(blk_get_aio_context(blk), sg, offset, align,
+    return dma_blk_io(sg, offset, align,
                       dma_blk_write_io_func, blk, cb, opaque,
                       DMA_DIRECTION_TO_DEVICE);
 }