From: Jason Wang <jasowang@redhat.com>
To: Li Wang <li.wang@windriver.com>
Cc: mst@redhat.com, kvm@vger.kernel.org,
virtualization@lists.linux-foundation.org,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] vhost: reduce stack usage in log_used
Date: Sun, 13 Sep 2020 22:42:15 -0400 (EDT) [thread overview]
Message-ID: <1199326218.16921082.1600051335160.JavaMail.zimbra@redhat.com> (raw)
In-Reply-To: <1599836979-4950-1-git-send-email-li.wang@windriver.com>
----- Original Message -----
> Fix the warning: [-Werror=-Wframe-larger-than=]
>
> drivers/vhost/vhost.c: In function log_used:
> drivers/vhost/vhost.c:1906:1:
> warning: the frame size of 1040 bytes is larger than 1024 bytes
>
> Signed-off-by: Li Wang <li.wang@windriver.com>
> ---
> drivers/vhost/vhost.c | 14 ++++++++++----
> 1 file changed, 10 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> index b45519c..41769de 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -1884,25 +1884,31 @@ static int log_write_hva(struct vhost_virtqueue *vq,
> u64 hva, u64 len)
>
> static int log_used(struct vhost_virtqueue *vq, u64 used_offset, u64 len)
> {
> - struct iovec iov[64];
> + struct iovec *iov;
> int i, ret;
>
> if (!vq->iotlb)
> return log_write(vq->log_base, vq->log_addr + used_offset, len);
>
> + iov = kcalloc(64, sizeof(*iov), GFP_KERNEL);
> + if (!iov)
> + return -ENOMEM;
Let's preallocate it in e.g vhost_net_open().
We don't want to fail the log due to -ENOMEM.
Thanks
> +
> ret = translate_desc(vq, (uintptr_t)vq->used + used_offset,
> len, iov, 64, VHOST_ACCESS_WO);
> if (ret < 0)
> - return ret;
> + goto out;
>
> for (i = 0; i < ret; i++) {
> ret = log_write_hva(vq, (uintptr_t)iov[i].iov_base,
> iov[i].iov_len);
> if (ret)
> - return ret;
> + goto out;
> }
>
> - return 0;
> +out:
> + kfree(iov);
> + return ret;
> }
>
> int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
> --
> 2.7.4
>
>
next prev parent reply other threads:[~2020-09-14 2:42 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-11 15:09 [PATCH] vhost: reduce stack usage in log_used Li Wang
2020-09-14 2:42 ` Jason Wang [this message]
2020-09-14 18:08 ` Li Wang
2020-09-15 7:53 ` Jason Wang
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