Re: [PATCH] virtio_ring: return an error pointer from vring_create_virtqueue()

[sashiko-bot@kernel.org]

> vring_create_virtqueue() and vring_create_virtqueue_map() return NULL
> on any failure, so the error returned from vring_alloc_queue_split()
> is lost and turned into -ENOMEM. This is especially misleading if
> vring_alloc_queue_split() rejects a queue size with -EINVAL (i.e. if
> queue size is not a power of two):
> 
>   virtio_blk virtio0: Bad virtqueue length 100
>   virtio_blk virtio0: probe with driver virtio_blk failed with error -12
> 
> So the error points whoever debugs it at an allocation failure that
> never happened.
> 
> Return an ERR_PTR() instead: the error from vring_alloc_queue_split()
> or vring_alloc_queue_packed(), or -ENOMEM when allocating the
> virtqueue itself fails. Make the callers, virtio_pci (modern and
> legacy), virtio_mmio, virtio_vdpa, virtio_ccw and virtio_uml, check
> with IS_ERR() and pass the error on. The error path in virtio_ccw
> deletes a non-NULL vq, so clear vq there before taking it.
> 
> Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
> Signed-off-by: Stjepan Poljak <stjepan.poljak@gmail.com>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261105193426.2999631-1-stjepan.poljak@gmail.com?part=1