On Tue, 5 Mar 2024 13:23:25 +0200 (EET), =?utf-8?q?Ilpo_J=C3=A4rvinen?= <ilpo.jarvinen@xxxxxxxxxxxxxxx> wrote:
> On Mon, 4 Mar 2024, Xuan Zhuo wrote:
>
> > Now, we pass multi parameters to find_vqs. These parameters
> > may work for transport or work for vring.
> >
> > And find_vqs has multi implements in many places:
> >
> > arch/um/drivers/virtio_uml.c
> > drivers/platform/mellanox/mlxbf-tmfifo.c
> > drivers/remoteproc/remoteproc_virtio.c
> > drivers/s390/virtio/virtio_ccw.c
> > drivers/virtio/virtio_mmio.c
> > drivers/virtio/virtio_pci_legacy.c
> > drivers/virtio/virtio_pci_modern.c
> > drivers/virtio/virtio_vdpa.c
> >
> > Every time, we try to add a new parameter, that is difficult.
> > We must change every find_vqs implement.
> >
> > One the other side, if we want to pass a parameter to vring,
> > we must change the call path from transport to vring.
> > Too many functions need to be changed.
> >
> > So it is time to refactor the find_vqs. We pass a structure
> > cfg to find_vqs(), that will be passed to vring by transport.
> >
> > Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
> > ---
> > arch/um/drivers/virtio_uml.c | 23 ++++-----
> > drivers/platform/mellanox/mlxbf-tmfifo.c | 13 ++----
> > drivers/remoteproc/remoteproc_virtio.c | 28 ++++++-----
> > drivers/s390/virtio/virtio_ccw.c | 29 ++++++------
> > drivers/virtio/virtio_mmio.c | 26 +++++------
> > drivers/virtio/virtio_pci_common.c | 59 +++++++++++-------------
> > drivers/virtio/virtio_pci_common.h | 9 +---
> > drivers/virtio/virtio_pci_legacy.c | 11 +++--
> > drivers/virtio/virtio_pci_modern.c | 33 +++++++------
> > drivers/virtio/virtio_vdpa.c | 36 +++++++--------
> > include/linux/virtio_config.h | 51 ++++++++++++++++----
> > 11 files changed, 172 insertions(+), 146 deletions(-)
> >
> > diff --git a/arch/um/drivers/virtio_uml.c b/arch/um/drivers/virtio_uml.c
> > index 8adca2000e51..c13dfeeb90c4 100644
> > --- a/arch/um/drivers/virtio_uml.c
> > +++ b/arch/um/drivers/virtio_uml.c
> > @@ -937,8 +937,8 @@ static int vu_setup_vq_call_fd(struct virtio_uml_device *vu_dev,
> > }
> >
> > static struct virtqueue *vu_setup_vq(struct virtio_device *vdev,
> > - unsigned index, vq_callback_t *callback,
> > - const char *name, bool ctx)
> > + unsigned index,
> > + struct virtio_vq_config *cfg)
> > {
> > struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
> > struct platform_device *pdev = vu_dev->pdev;
> > @@ -953,10 +953,12 @@ static struct virtqueue *vu_setup_vq(struct virtio_device *vdev,
> > goto error_kzalloc;
> > }
> > snprintf(info->name, sizeof(info->name), "%s.%d-%s", pdev->name,
> > - pdev->id, name);
> > + pdev->id, cfg->names[cfg->cfg_idx]);
> >
> > vq = vring_create_virtqueue(index, num, PAGE_SIZE, vdev, true, true,
> > - ctx, vu_notify, callback, info->name);
> > + cfg->ctx ? cfg->ctx[cfg->cfg_idx] : false,
>
> Based on the commit message, I don't understand why this transformation
> was made. It's perhaps some artifact of moving things around but please
> state it in the commit message because this isn't 1:1 transformation
> which would be just ctx -> cfg->ctx
You can see the caller:
ctx ? ctx[i] : false
ctx maybe array or null.
vring_create_virtqueue just accept the bool. So we pass the cfg->ctx[cfg->
cfg_idx] if it is array.
>
> > + vu_notify,
> > + cfg->callbacks[cfg->cfg_idx], info->name);
> > if (!vq) {
> > rc = -ENOMEM;
> > goto error_create;
>
>
> > diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
> > index b655fccaf773..a9ae03904dcf 100644
> > --- a/drivers/virtio/virtio_pci_common.c
> > +++ b/drivers/virtio/virtio_pci_common.c
> > @@ -172,9 +172,7 @@ static int vp_request_msix_vectors(struct virtio_device *vdev, int nvectors,
> > }
> >
> > static struct virtqueue *vp_setup_vq(struct virtio_device *vdev, unsigned int index,
> > - void (*callback)(struct virtqueue *vq),
> > - const char *name,
> > - bool ctx,
> > + struct virtio_vq_config *cfg,
> > u16 msix_vec)
> > {
> > struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> > @@ -186,13 +184,13 @@ static struct virtqueue *vp_setup_vq(struct virtio_device *vdev, unsigned int in
> > if (!info)
> > return ERR_PTR(-ENOMEM);
> >
> > - vq = vp_dev->setup_vq(vp_dev, info, index, callback, name, ctx,
> > + vq = vp_dev->setup_vq(vp_dev, info, index, cfg,
> > msix_vec);
>
> Should now easily fit to one line.
YES.
>
>
> > @@ -126,10 +124,7 @@ bool vp_notify(struct virtqueue *vq);
> > /* the config->del_vqs() implementation */
> > void vp_del_vqs(struct virtio_device *vdev);
> > /* the config->find_vqs() implementation */
> > -int vp_find_vqs(struct virtio_device *vdev, unsigned int nvqs,
> > - struct virtqueue *vqs[], vq_callback_t *callbacks[],
> > - const char * const names[], const bool *ctx,
> > - struct irq_affinity *desc);
> > +int vp_find_vqs(struct virtio_device *vdev, struct virtio_vq_config *cfg);
>
> Without knowing better, do you expect cfg is mutated inside vp_find_vqs()?
> If not, mark it as const.
It can be changed.
cfg_idx will be updated.
>
> > diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
> > index da9b271b54db..1df8634d1258 100644
> > --- a/include/linux/virtio_config.h
> > +++ b/include/linux/virtio_config.h
> > @@ -96,6 +96,20 @@ typedef void vq_callback_t(struct virtqueue *);
> > * @create_avq: create admin virtqueue resource.
> > * @destroy_avq: destroy admin virtqueue resource.
> > */
> > +
> > +struct virtio_vq_config {
> > + unsigned int nvqs;
> > +
> > + /* the vq index may not eq to the cfg index of the other array items */
>
> Can you try to make this comment clearer, as is I don't understand what it
> means. E.g. what is "the other array"? not eq = not equal ?
The names, ctx, callbacks are array.
In the process of vq setup, we need to know the current index.
But we can not use the vq->index, because maybe the one of names
is null, so we must record the current index.
The comment will be updated.
>
> > + unsigned int cfg_idx;
> > +
> > + struct virtqueue **vqs;
> > + vq_callback_t **callbacks;
> > + const char *const *names;
> > + const bool *ctx;
> > + struct irq_affinity *desc;
> > +};
>
> The placement of the struct is wrong. Now the documentation of struct
> virtio_config_ops is above your struct!?!
>
> Please also document the members of the newly added struct with kerneldoc.
Will fix.
Thanks.
>
> > +
> > struct virtio_config_ops {
> > void (*get)(struct virtio_device *vdev, unsigned offset,
> > void *buf, unsigned len);
> > @@ -105,10 +119,7 @@ struct virtio_config_ops {
> > u8 (*get_status)(struct virtio_device *vdev);
> > void (*set_status)(struct virtio_device *vdev, u8 status);
> > void (*reset)(struct virtio_device *vdev);
> > - int (*find_vqs)(struct virtio_device *, unsigned nvqs,
> > - struct virtqueue *vqs[], vq_callback_t *callbacks[],
> > - const char * const names[], const bool *ctx,
> > - struct irq_affinity *desc);
> > + int (*find_vqs)(struct virtio_device *vdev, struct virtio_vq_config *cfg);
> > void (*del_vqs)(struct virtio_device *);
> > void (*synchronize_cbs)(struct virtio_device *);
> > u64 (*get_features)(struct virtio_device *vdev);
>
>
> --
> i.
>
