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Re: [Qemu-devel] [STABLE][PATCH 4/4] Fix DMA API when handling an immedi
From: |
Mark McLoughlin |
Subject: |
Re: [Qemu-devel] [STABLE][PATCH 4/4] Fix DMA API when handling an immediate error from block layer |
Date: |
Thu, 14 May 2009 12:39:54 +0100 |
On Thu, 2009-05-14 at 11:56 +0100, Mark McLoughlin wrote:
> From: Avi Kivity <address@hidden>
>
> The block layer may signal an immediate error on an asynchronous request
> by returning NULL. The DMA API did not handle this correctly, returning
> an AIO request which would never complete (and which would crash if
> cancelled).
>
> Fix by detecting the failure and propagating it.
>
> Signed-off-by: Avi Kivity <address@hidden>
Signed-off-by: Mark McLoughlin <address@hidden>
> ---
> dma-helpers.c | 27 +++++++++++++++++++++------
> 1 files changed, 21 insertions(+), 6 deletions(-)
>
> diff --git a/dma-helpers.c b/dma-helpers.c
> index 96a120c..1469e34 100644
> --- a/dma-helpers.c
> +++ b/dma-helpers.c
> @@ -70,20 +70,26 @@ static void continue_after_map_failure(void *opaque)
> qemu_bh_schedule(dbs->bh);
> }
>
> -static void dma_bdrv_cb(void *opaque, int ret)
> +static void dma_bdrv_unmap(DMAAIOCB *dbs)
> {
> - 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,
> dbs->iov.iov[i].iov_len, !dbs->is_write,
> dbs->iov.iov[i].iov_len);
> }
> +}
> +
> +void dma_bdrv_cb(void *opaque, int ret)
> +{
> + DMAAIOCB *dbs = (DMAAIOCB *)opaque;
> + target_phys_addr_t cur_addr, cur_len;
> + void *mem;
> +
> + dbs->acb = NULL;
> + dbs->sector_num += dbs->iov.size / 512;
> + dma_bdrv_unmap(dbs);
> qemu_iovec_reset(&dbs->iov);
>
> if (dbs->sg_cur_index == dbs->sg->nsg || ret < 0) {
> @@ -119,6 +125,11 @@ static void dma_bdrv_cb(void *opaque, int ret)
> dbs->acb = bdrv_aio_readv(dbs->bs, dbs->sector_num, &dbs->iov,
> dbs->iov.size / 512, dma_bdrv_cb, dbs);
> }
> + if (!dbs->acb) {
> + dma_bdrv_unmap(dbs);
> + qemu_iovec_destroy(&dbs->iov);
> + return;
> + }
> }
>
> static BlockDriverAIOCB *dma_bdrv_io(
> @@ -138,6 +149,10 @@ static BlockDriverAIOCB *dma_bdrv_io(
> dbs->bh = NULL;
> qemu_iovec_init(&dbs->iov, sg->nsg);
> dma_bdrv_cb(dbs, 0);
> + if (!dbs->acb) {
> + qemu_aio_release(dbs);
> + return NULL;
> + }
> return &dbs->common;
> }
>
[Qemu-devel] Re: [STABLE][PATCH 0/4] Rebase more aio dma cancellation work, Avi Kivity, 2009/05/14
Re: [Qemu-devel] [STABLE][PATCH 0/4] Rebase more aio dma cancellation work, Anthony Liguori, 2009/05/14