Re: [PATCH] driver, virtio: Modify the err hanlding logic

From: Rusty Russell
Date: Wed Apr 27 2011 - 02:08:17 EST


On Wed, 20 Apr 2011 21:21:59 +0800, Liu Yuan <namei.unix@xxxxxxxxx> wrote:
> From: Liu Yuan <tailai.ly@xxxxxxxxxx>
>
> In the function vp_request_msix_vectors(), when
> pci_enable_msix() returns 0, there will be
> redundant double checks for 'err'. This patch
> fixes it to avoid the unnecessary check.
>
> Signed-off-by: Liu Yuan <tailai.ly@xxxxxxxxxx>
> ---
> drivers/virtio/virtio_pci.c | 7 ++++---
> 1 files changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c
> index 4fb5b2b..2c05376 100644
> --- a/drivers/virtio/virtio_pci.c
> +++ b/drivers/virtio/virtio_pci.c
> @@ -298,10 +298,11 @@ static int vp_request_msix_vectors(struct virtio_device *vdev, int nvectors,
>
> /* pci_enable_msix returns positive if we can't get this many. */
> err = pci_enable_msix(vp_dev->pci_dev, vp_dev->msix_entries, nvectors);
> - if (err > 0)
> - err = -ENOSPC;
> - if (err)
> + if (err) {
> + if (err > 0)
> + err = -ENOSPC;
> goto error;
> + }
> vp_dev->msix_vectors = nvectors;
> vp_dev->msix_enabled = 1;

This patch is extremely marginal. It theoretically improves efficiency,
but it's in a case we don't care about. The code is quite clear.

My general policy for such marginal improvements is to only accept them
from the maintainer him/herself, so I won't be taking this patch.

Of course, if you produce a series of fixes to the driver with such a
patch as a cleaner, I'm lazy enough that I'd take them all at once :)

Thanks,
Rusty.
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