From e969fed542cae08cb11d666efac4f7c5d624d09f Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Sun, 26 Jul 2009 15:48:08 +0300 Subject: virtio: refactor find_vqs 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) Tested-by: Amit Shah Signed-off-by: Michael S. Tsirkin Signed-off-by: Rusty Russell diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c index a1cb1a1..248e00e 100644 --- a/drivers/virtio/virtio_pci.c +++ b/drivers/virtio/virtio_pci.c @@ -52,8 +52,10 @@ struct virtio_pci_device char (*msix_names)[256]; /* Number of available vectors */ unsigned msix_vectors; - /* Vectors allocated */ + /* Vectors allocated, excluding per-vq vectors if any */ unsigned msix_used_vectors; + /* Whether we have vector per vq */ + bool per_vq_vectors; }; /* Constants for MSI-X */ @@ -278,27 +280,24 @@ static void vp_free_vectors(struct virtio_device *vdev) vp_dev->msix_entries = NULL; } -static int vp_enable_msix(struct pci_dev *dev, struct msix_entry *entries, - int *options, int noptions) -{ - int i; - for (i = 0; i < noptions; ++i) - if (!pci_enable_msix(dev, entries, options[i])) - return options[i]; - return -EBUSY; -} - -static int vp_request_vectors(struct virtio_device *vdev, unsigned max_vqs) +static int vp_request_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; - /* We want at most one vector per queue and one for config changes. - * Fallback to separate vectors for config and a shared for queues. - * Finally fall back to regular interrupts. */ - int options[] = { max_vqs + 1, 2 }; - int nvectors = max(options[0], options[1]); + + 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); @@ -312,41 +311,34 @@ static int vp_request_vectors(struct virtio_device *vdev, unsigned max_vqs) for (i = 0; i < nvectors; ++i) vp_dev->msix_entries[i].entry = i; - err = vp_enable_msix(vp_dev->pci_dev, vp_dev->msix_entries, - options, ARRAY_SIZE(options)); - if (err < 0) { - /* Can't allocate enough 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) - goto error; - vp_dev->intx_enabled = 1; - } else { - vp_dev->msix_vectors = err; - vp_dev->msix_enabled = 1; - - /* Set the vector used for configuration */ - v = vp_dev->msix_used_vectors; - snprintf(vp_dev->msix_names[v], sizeof *vp_dev->msix_names, - "%s-config", name); - err = request_irq(vp_dev->msix_entries[v].vector, - vp_config_changed, 0, vp_dev->msix_names[v], - vp_dev); - if (err) - goto error; - ++vp_dev->msix_used_vectors; + err = pci_enable_msix(vp_dev->pci_dev, vp_dev->msix_entries, nvectors); + if (err > 0) + err = -ENOSPC; + if (err) + goto error; + vp_dev->msix_vectors = nvectors; + vp_dev->msix_enabled = 1; + + /* Set the vector used for configuration */ + v = vp_dev->msix_used_vectors; + snprintf(vp_dev->msix_names[v], sizeof *vp_dev->msix_names, + "%s-config", name); + err = request_irq(vp_dev->msix_entries[v].vector, + vp_config_changed, 0, vp_dev->msix_names[v], + vp_dev); + if (err) + goto error; + ++vp_dev->msix_used_vectors; - iowrite16(v, vp_dev->ioaddr + VIRTIO_MSI_CONFIG_VECTOR); - /* Verify we had enough resources to assign the vector */ - v = ioread16(vp_dev->ioaddr + VIRTIO_MSI_CONFIG_VECTOR); - if (v == VIRTIO_MSI_NO_VECTOR) { - err = -EBUSY; - goto error; - } + iowrite16(v, vp_dev->ioaddr + VIRTIO_MSI_CONFIG_VECTOR); + /* Verify we had enough resources to assign the vector */ + v = ioread16(vp_dev->ioaddr + VIRTIO_MSI_CONFIG_VECTOR); + if (v == VIRTIO_MSI_NO_VECTOR) { + err = -EBUSY; + goto error; } - if (vp_dev->msix_vectors && vp_dev->msix_vectors != max_vqs + 1) { + if (!per_vq_vectors) { /* Shared vector for all VQs */ v = vp_dev->msix_used_vectors; snprintf(vp_dev->msix_names[v], sizeof *vp_dev->msix_names, @@ -366,13 +358,14 @@ error: static struct virtqueue *vp_find_vq(struct virtio_device *vdev, unsigned index, void (*callback)(struct virtqueue *vq), - const char *name) + const char *name, + u16 vector) { struct virtio_pci_device *vp_dev = to_vp_device(vdev); struct virtio_pci_vq_info *info; struct virtqueue *vq; unsigned long flags, size; - u16 num, vector; + u16 num; int err; /* Select the queue we're interested in */ @@ -391,7 +384,7 @@ static struct virtqueue *vp_find_vq(struct virtio_device *vdev, unsigned index, info->queue_index = index; info->num = num; - info->vector = VIRTIO_MSI_NO_VECTOR; + info->vector = vector; size = PAGE_ALIGN(vring_size(num, VIRTIO_PCI_VRING_ALIGN)); info->queue = alloc_pages_exact(size, GFP_KERNEL|__GFP_ZERO); @@ -415,22 +408,7 @@ static struct virtqueue *vp_find_vq(struct virtio_device *vdev, unsigned index, vq->priv = info; info->vq = vq; - /* allocate per-vq vector if available and necessary */ - if (callback && vp_dev->msix_used_vectors < vp_dev->msix_vectors) { - vector = vp_dev->msix_used_vectors; - snprintf(vp_dev->msix_names[vector], sizeof *vp_dev->msix_names, - "%s-%s", dev_name(&vp_dev->vdev.dev), name); - err = request_irq(vp_dev->msix_entries[vector].vector, - vring_interrupt, 0, - vp_dev->msix_names[vector], vq); - if (err) - goto out_request_irq; - info->vector = vector; - ++vp_dev->msix_used_vectors; - } else - vector = VP_MSIX_VQ_VECTOR; - - if (callback && vp_dev->msix_enabled) { + 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) { @@ -446,11 +424,6 @@ static struct virtqueue *vp_find_vq(struct virtio_device *vdev, unsigned index, return vq; out_assign: - if (info->vector != VIRTIO_MSI_NO_VECTOR) { - free_irq(vp_dev->msix_entries[info->vector].vector, vq); - --vp_dev->msix_used_vectors; - } -out_request_irq: vring_del_virtqueue(vq); out_activate_queue: iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN); @@ -472,9 +445,6 @@ static void vp_del_vq(struct virtqueue *vq) iowrite16(info->queue_index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL); - if (info->vector != VIRTIO_MSI_NO_VECTOR) - free_irq(vp_dev->msix_entries[info->vector].vector, vq); - if (vp_dev->msix_enabled) { iowrite16(VIRTIO_MSI_NO_VECTOR, vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR); @@ -495,36 +465,62 @@ static void vp_del_vq(struct virtqueue *vq) /* the config->del_vqs() implementation */ static void vp_del_vqs(struct virtio_device *vdev) { + struct virtio_pci_device *vp_dev = to_vp_device(vdev); struct virtqueue *vq, *n; + struct virtio_pci_vq_info *info; - list_for_each_entry_safe(vq, n, &vdev->vqs, list) + list_for_each_entry_safe(vq, n, &vdev->vqs, list) { + info = vq->priv; + if (vp_dev->per_vq_vectors) + free_irq(vp_dev->msix_entries[info->vector].vector, vq); vp_del_vq(vq); + } + vp_dev->per_vq_vectors = false; vp_free_vectors(vdev); } -/* the config->find_vqs() implementation */ -static int vp_find_vqs(struct virtio_device *vdev, unsigned nvqs, - struct virtqueue *vqs[], - vq_callback_t *callbacks[], - const char *names[]) +static int vp_try_to_find_vqs(struct virtio_device *vdev, unsigned nvqs, + struct virtqueue *vqs[], + vq_callback_t *callbacks[], + const char *names[], + int nvectors, + bool per_vq_vectors) { - int vectors = 0; - int i, err; - - /* How many vectors would we like? */ - for (i = 0; i < nvqs; ++i) - if (callbacks[i]) - ++vectors; + struct virtio_pci_device *vp_dev = to_vp_device(vdev); + u16 vector; + int i, err, allocated_vectors; - err = vp_request_vectors(vdev, vectors); + err = vp_request_vectors(vdev, nvectors, per_vq_vectors); if (err) goto error_request; + vp_dev->per_vq_vectors = per_vq_vectors; + allocated_vectors = vp_dev->msix_used_vectors; for (i = 0; i < nvqs; ++i) { - vqs[i] = vp_find_vq(vdev, i, callbacks[i], names[i]); - if (IS_ERR(vqs[i])) + if (!callbacks[i] || !vp_dev->msix_enabled) + vector = VIRTIO_MSI_NO_VECTOR; + else if (vp_dev->per_vq_vectors) + vector = allocated_vectors++; + else + vector = VP_MSIX_VQ_VECTOR; + vqs[i] = vp_find_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]); + err = request_irq(vp_dev->msix_entries[vector].vector, + vring_interrupt, 0, + vp_dev->msix_names[vector], vqs[i]); + if (err) { + vp_del_vq(vqs[i]); + goto error_find; + } + } } return 0; @@ -532,7 +528,37 @@ error_find: vp_del_vqs(vdev); error_request: - return PTR_ERR(vqs[i]); + return err; +} + +/* the config->find_vqs() implementation */ +static int vp_find_vqs(struct virtio_device *vdev, unsigned nvqs, + struct virtqueue *vqs[], + vq_callback_t *callbacks[], + const char *names[]) +{ + int vectors = 0; + int i, uninitialized_var(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); + if (!err) + return 0; + /* Fallback to separate vectors for config and a shared for queues. */ + err = vp_try_to_find_vqs(vdev, nvqs, vqs, callbacks, names, + 2, 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; } static struct virtio_config_ops virtio_pci_config_ops = { -- cgit v0.10.2