On Tue, Jul 28, 2009 at 12:44:31PM +0930, Rusty Russell wrote: > On Mon, 27 Jul 2009 01:17:09 am Michael S. Tsirkin wrote: > > This refactors find_vqs, making it more readable and robust, and fixing > > two regressions from 2.6.30: > > - double free_irq causing BUG_ON on device removal > > - probe failure when vq can't be assigned to msi-x vector > > (reported on old host kernels) > > > > An older version of this patch was tested by Amit Shah. > > OK, I've applied both of these; I'd like to see a new test by Amit to > make sure tho. > > I really like this cleanup! I looked harder at this code, and my best > attempts to untangle it further came to very little. This is what I > ended up with, but it's all cosmetic and can wait until next merge window. > See what you think. > > Thanks! > Rusty. > > virtio_pci: minor MSI-X cleanups > > 1) Rename vp_request_vectors to vp_request_msix_vectors, and take > non-MSI-X case out to caller.
I'm not sure this change was for the best: we still have a separate code path under if !use_msix, only in another place now. See below. And this seems to break the symmetry between request_ and free_vectors. > 2) Comment weird pci_enable_msix API > 3) Rename vp_find_vq to setup_vq. > 4) Fix spaces to tabs > 5) Make nvectors calc internal to vp_try_to_find_vqs() The other changes look good to me. > > Signed-off-by: Rusty Russell <[email protected]> > --- > drivers/virtio/virtio_pci.c | 84 > +++++++++++++++++++++++--------------------- > 1 file changed, 45 insertions(+), 39 deletions(-) > > diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c > --- a/drivers/virtio/virtio_pci.c > +++ b/drivers/virtio/virtio_pci.c > @@ -280,25 +280,14 @@ static void vp_free_vectors(struct virti > vp_dev->msix_entries = NULL; > } > > -static int vp_request_vectors(struct virtio_device *vdev, int nvectors, > - bool per_vq_vectors) > +static int vp_request_msix_vectors(struct virtio_device *vdev, int nvectors, > + bool per_vq_vectors) > { > struct virtio_pci_device *vp_dev = to_vp_device(vdev); > const char *name = dev_name(&vp_dev->vdev.dev); > unsigned i, v; > int err = -ENOMEM; > > - if (!nvectors) { > - /* Can't allocate MSI-X vectors, use regular interrupt */ > - vp_dev->msix_vectors = 0; > - err = request_irq(vp_dev->pci_dev->irq, vp_interrupt, > - IRQF_SHARED, name, vp_dev); > - if (err) > - return err; > - vp_dev->intx_enabled = 1; > - return 0; > - } > - > vp_dev->msix_entries = kmalloc(nvectors * sizeof *vp_dev->msix_entries, > GFP_KERNEL); > if (!vp_dev->msix_entries) > @@ -311,6 +300,7 @@ static int vp_request_vectors(struct vir > for (i = 0; i < nvectors; ++i) > vp_dev->msix_entries[i].entry = i; > > + /* 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; > @@ -356,10 +346,10 @@ error: > return err; > } > > -static struct virtqueue *vp_find_vq(struct virtio_device *vdev, unsigned > index, > - void (*callback)(struct virtqueue *vq), > - const char *name, > - u16 vector) > +static struct virtqueue *setup_vq(struct virtio_device *vdev, unsigned index, > + void (*callback)(struct virtqueue *vq), > + const char *name, > + u16 vector) > { > struct virtio_pci_device *vp_dev = to_vp_device(vdev); > struct virtio_pci_vq_info *info; > @@ -408,7 +398,7 @@ static struct virtqueue *vp_find_vq(stru > vq->priv = info; > info->vq = vq; > > - if (vector != VIRTIO_MSI_NO_VECTOR) { > + if (vector != VIRTIO_MSI_NO_VECTOR) { > iowrite16(vector, vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR); > vector = ioread16(vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR); > if (vector == VIRTIO_MSI_NO_VECTOR) { > @@ -484,14 +474,36 @@ static int vp_try_to_find_vqs(struct vir > struct virtqueue *vqs[], > vq_callback_t *callbacks[], > const char *names[], > - int nvectors, > + bool use_msix, > bool per_vq_vectors) > { > struct virtio_pci_device *vp_dev = to_vp_device(vdev); > u16 vector; > - int i, err, allocated_vectors; > + int i, err, nvectors, allocated_vectors; > > - err = vp_request_vectors(vdev, nvectors, per_vq_vectors); > + if (!use_msix) { > + /* Old style: one normal interrupt for change and all vqs. */ > + vp_dev->msix_vectors = 0; > + vp_dev->per_vq_vectors = false; > + err = request_irq(vp_dev->pci_dev->irq, vp_interrupt, > + IRQF_SHARED, dev_name(&vdev->dev), vp_dev); > + if (!err) > + vp_dev->intx_enabled = 1; shorter as vp_dev->intx_enabled = !err > + return err; Is that all? Don't we need to create the vqs? > + } > + > + if (per_vq_vectors) { > + /* Best option: one for change interrupt, one per vq. */ > + nvectors = 1; > + for (i = 0; i < nvqs; ++i) > + if (callbacks[i]) > + ++nvectors; > + } else { > + /* Second best: one for change, shared one for all vqs. */ > + nvectors = 2; > + } > + > + err = vp_request_msix_vectors(vdev, nvectors, per_vq_vectors); > if (err) > goto error_request; > > @@ -504,15 +516,17 @@ static int vp_try_to_find_vqs(struct vir > vector = allocated_vectors++; > else > vector = VP_MSIX_VQ_VECTOR; > - vqs[i] = vp_find_vq(vdev, i, callbacks[i], names[i], vector); > + vqs[i] = setup_vq(vdev, i, callbacks[i], names[i], vector); > if (IS_ERR(vqs[i])) { > err = PTR_ERR(vqs[i]); > goto error_find; > } > /* allocate per-vq irq if available and necessary */ > if (vp_dev->per_vq_vectors && vector != VIRTIO_MSI_NO_VECTOR) { > - snprintf(vp_dev->msix_names[vector], sizeof > *vp_dev->msix_names, > - "%s-%s", dev_name(&vp_dev->vdev.dev), > names[i]); > + snprintf(vp_dev->msix_names[vector], > + sizeof *vp_dev->msix_names, > + "%s-%s", > + dev_name(&vp_dev->vdev.dev), names[i]); > err = request_irq(vp_dev->msix_entries[vector].vector, > vring_interrupt, 0, > vp_dev->msix_names[vector], vqs[i]); > @@ -537,28 +551,20 @@ static int vp_find_vqs(struct virtio_dev > vq_callback_t *callbacks[], > const char *names[]) > { > - int vectors = 0; > - int i, uninitialized_var(err); > + int err; > > - /* How many vectors would we like? */ > - for (i = 0; i < nvqs; ++i) > - if (callbacks[i]) > - ++vectors; > - > - /* We want at most one vector per queue and one for config changes. */ > - err = vp_try_to_find_vqs(vdev, nvqs, vqs, callbacks, names, > - vectors + 1, true); > + /* Try MSI-X with one vector per queue. */ > + err = vp_try_to_find_vqs(vdev, nvqs, vqs, callbacks, names, true, true); > if (!err) > return 0; > - /* Fallback to separate vectors for config and a shared for queues. */ > + /* Fallback: MSI-X with one vector for config, one shared for queues. */ > err = vp_try_to_find_vqs(vdev, nvqs, vqs, callbacks, names, > - 2, false); > + true, false); > if (!err) > return 0; > /* Finally fall back to regular interrupts. */ > - err = vp_try_to_find_vqs(vdev, nvqs, vqs, callbacks, names, > - 0, false); > - return err; > + return vp_try_to_find_vqs(vdev, nvqs, vqs, callbacks, names, > + false, false); > } > > static struct virtio_config_ops virtio_pci_config_ops = { _______________________________________________ Virtualization mailing list [email protected] https://lists.linux-foundation.org/mailman/listinfo/virtualization
