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. 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() 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; + return err; + } + + 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
