[v3,14/21] raw-win32: Handle failure for potentially large allocations

Some code in the block layer makes potentially huge allocations. Failure
is not completely unexpected there, so avoid aborting qemu and handle
out-of-memory situations gracefully.

This patch addresses the allocations in the raw-win32 block driver.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 block/win32-aio.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

The Tuesday 03 Jun 2014 à 15:10:55 (+0200), Kevin Wolf wrote :
> Some code in the block layer makes potentially huge allocations. Failure
> is not completely unexpected there, so avoid aborting qemu and handle
> out-of-memory situations gracefully.
> 
> This patch addresses the allocations in the raw-win32 block driver.
> 
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
>  block/win32-aio.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/block/win32-aio.c b/block/win32-aio.c
> index 5d1d199..b8320ce 100644
> --- a/block/win32-aio.c
> +++ b/block/win32-aio.c
> @@ -138,7 +138,10 @@ BlockDriverAIOCB *win32_aio_submit(BlockDriverState *bs,
>      waiocb->is_read = (type == QEMU_AIO_READ);
>  
>      if (qiov->niov > 1) {
> -        waiocb->buf = qemu_blockalign(bs, qiov->size);
> +        waiocb->buf = qemu_try_blockalign(bs, qiov->size);
> +        if (waiocb->buf == NULL) {
Would taking care that errno is still -ENOMEM at the failure exit of the fonction
usefull for the potentials callers ?

> +            goto out;
> +        }
>          if (type & QEMU_AIO_WRITE) {
>              iov_to_buf(qiov->iov, qiov->niov, 0, waiocb->buf, qiov->size);
>          }
> @@ -167,6 +170,7 @@ BlockDriverAIOCB *win32_aio_submit(BlockDriverState *bs,
>  
>  out_dec_count:
>      aio->count--;
> +out:
>      qemu_aio_release(waiocb);
>      return NULL;
>  }
> -- 
> 1.8.3.1
>

Am 03.06.2014 um 17:46 hat Benoît Canet geschrieben:
> The Tuesday 03 Jun 2014 à 15:10:55 (+0200), Kevin Wolf wrote :
> > Some code in the block layer makes potentially huge allocations. Failure
> > is not completely unexpected there, so avoid aborting qemu and handle
> > out-of-memory situations gracefully.
> > 
> > This patch addresses the allocations in the raw-win32 block driver.
> > 
> > Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> > Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
> > ---
> >  block/win32-aio.c | 6 +++++-
> >  1 file changed, 5 insertions(+), 1 deletion(-)
> > 
> > diff --git a/block/win32-aio.c b/block/win32-aio.c
> > index 5d1d199..b8320ce 100644
> > --- a/block/win32-aio.c
> > +++ b/block/win32-aio.c
> > @@ -138,7 +138,10 @@ BlockDriverAIOCB *win32_aio_submit(BlockDriverState *bs,
> >      waiocb->is_read = (type == QEMU_AIO_READ);
> >  
> >      if (qiov->niov > 1) {
> > -        waiocb->buf = qemu_blockalign(bs, qiov->size);
> > +        waiocb->buf = qemu_try_blockalign(bs, qiov->size);
> > +        if (waiocb->buf == NULL) {
> Would taking care that errno is still -ENOMEM at the failure exit of the fonction
> usefull for the potentials callers ?

There are only two callers and they don't care about errno.

Kevin