提交 c3adb5b9 编写于 作者: P Paolo Bonzini 提交者: Kevin Wolf

dma-helpers: rewrite completion/cancellation

This fixes various problems with completion/cancellation:

* if the io_func fails to get an AIOCB, the callback wasn't called

* If DMA encounters a bounce buffer conflict, and the DMA operation is
canceled before the bottom half fires, bad things happen.

* memory is not unmapped after cancellation, again causing problems
when doing DMA to I/O areas

* cancellation could leak the iovec

* the callback was missed if the I/O operation failed without returning
an AIOCB

and probably more that I've missed.  The patch fixes them by sharing
the cleanup code between completion and cancellation.  The dma_bdrv_cb
now returns a boolean completed/not completed flag, and the wrapper
dma_continue takes care of tasks to do upon completion.

Most of these are basically impossible in practice, but it is better
to be tidy...
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
上级 10dc8aef
...@@ -43,6 +43,7 @@ typedef struct { ...@@ -43,6 +43,7 @@ typedef struct {
QEMUSGList *sg; QEMUSGList *sg;
uint64_t sector_num; uint64_t sector_num;
bool to_dev; bool to_dev;
bool in_cancel;
int sg_cur_index; int sg_cur_index;
target_phys_addr_t sg_cur_byte; target_phys_addr_t sg_cur_byte;
QEMUIOVector iov; QEMUIOVector iov;
...@@ -58,7 +59,7 @@ static void reschedule_dma(void *opaque) ...@@ -58,7 +59,7 @@ static void reschedule_dma(void *opaque)
qemu_bh_delete(dbs->bh); qemu_bh_delete(dbs->bh);
dbs->bh = NULL; dbs->bh = NULL;
dma_bdrv_cb(opaque, 0); dma_bdrv_cb(dbs, 0);
} }
static void continue_after_map_failure(void *opaque) static void continue_after_map_failure(void *opaque)
...@@ -78,6 +79,26 @@ static void dma_bdrv_unmap(DMAAIOCB *dbs) ...@@ -78,6 +79,26 @@ static void dma_bdrv_unmap(DMAAIOCB *dbs)
dbs->iov.iov[i].iov_len, !dbs->to_dev, dbs->iov.iov[i].iov_len, !dbs->to_dev,
dbs->iov.iov[i].iov_len); dbs->iov.iov[i].iov_len);
} }
qemu_iovec_reset(&dbs->iov);
}
static void dma_complete(DMAAIOCB *dbs, int ret)
{
dma_bdrv_unmap(dbs);
if (dbs->common.cb) {
dbs->common.cb(dbs->common.opaque, ret);
}
qemu_iovec_destroy(&dbs->iov);
if (dbs->bh) {
qemu_bh_delete(dbs->bh);
dbs->bh = NULL;
}
if (!dbs->in_cancel) {
/* Requests may complete while dma_aio_cancel is in progress. In
* this case, the AIOCB should not be released because it is still
* referenced by dma_aio_cancel. */
qemu_aio_release(dbs);
}
} }
static void dma_bdrv_cb(void *opaque, int ret) static void dma_bdrv_cb(void *opaque, int ret)
...@@ -89,12 +110,9 @@ static void dma_bdrv_cb(void *opaque, int ret) ...@@ -89,12 +110,9 @@ static void dma_bdrv_cb(void *opaque, int ret)
dbs->acb = NULL; dbs->acb = NULL;
dbs->sector_num += dbs->iov.size / 512; dbs->sector_num += dbs->iov.size / 512;
dma_bdrv_unmap(dbs); dma_bdrv_unmap(dbs);
qemu_iovec_reset(&dbs->iov);
if (dbs->sg_cur_index == dbs->sg->nsg || ret < 0) { if (dbs->sg_cur_index == dbs->sg->nsg || ret < 0) {
dbs->common.cb(dbs->common.opaque, ret); dma_complete(dbs, ret);
qemu_iovec_destroy(&dbs->iov);
qemu_aio_release(dbs);
return; return;
} }
...@@ -120,9 +138,7 @@ static void dma_bdrv_cb(void *opaque, int ret) ...@@ -120,9 +138,7 @@ static void dma_bdrv_cb(void *opaque, int ret)
dbs->acb = dbs->io_func(dbs->bs, dbs->sector_num, &dbs->iov, dbs->acb = dbs->io_func(dbs->bs, dbs->sector_num, &dbs->iov,
dbs->iov.size / 512, dma_bdrv_cb, dbs); dbs->iov.size / 512, dma_bdrv_cb, dbs);
if (!dbs->acb) { if (!dbs->acb) {
dma_bdrv_unmap(dbs); dma_complete(dbs, -EIO);
qemu_iovec_destroy(&dbs->iov);
return;
} }
} }
...@@ -131,8 +147,14 @@ static void dma_aio_cancel(BlockDriverAIOCB *acb) ...@@ -131,8 +147,14 @@ static void dma_aio_cancel(BlockDriverAIOCB *acb)
DMAAIOCB *dbs = container_of(acb, DMAAIOCB, common); DMAAIOCB *dbs = container_of(acb, DMAAIOCB, common);
if (dbs->acb) { if (dbs->acb) {
bdrv_aio_cancel(dbs->acb); BlockDriverAIOCB *acb = dbs->acb;
dbs->acb = NULL;
dbs->in_cancel = true;
bdrv_aio_cancel(acb);
dbs->in_cancel = false;
} }
dbs->common.cb = NULL;
dma_complete(dbs, 0);
} }
static AIOPool dma_aio_pool = { static AIOPool dma_aio_pool = {
...@@ -158,10 +180,6 @@ BlockDriverAIOCB *dma_bdrv_io( ...@@ -158,10 +180,6 @@ BlockDriverAIOCB *dma_bdrv_io(
dbs->bh = NULL; dbs->bh = NULL;
qemu_iovec_init(&dbs->iov, sg->nsg); qemu_iovec_init(&dbs->iov, sg->nsg);
dma_bdrv_cb(dbs, 0); dma_bdrv_cb(dbs, 0);
if (!dbs->acb) {
qemu_aio_release(dbs);
return NULL;
}
return &dbs->common; return &dbs->common;
} }
......
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