[PATCH 1/9] virtio_pci: remove struct virtio_pci_vq_info

Christoph Hellwig
2017-01-27T08:19:42Z

We don't really need struct virtio_pci_vq_info, as most field in there
are redundant:

- the vq backpointer is not strictly neede to start with
- the entry in the vqs list is not needed - the generic virtqueue already
has list, we only need to check if it has a callback to get the same
semantics
- we can use a simple array to look up the MSI-X vec if needed.
- That simple array now also duoble serves to replace the per_vq_vectors
flag

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
drivers/virtio/virtio_pci_common.c | 117 +++++++++++--------------------------
drivers/virtio/virtio_pci_common.h | 25 +-------
drivers/virtio/virtio_pci_legacy.c | 6 +-
drivers/virtio/virtio_pci_modern.c | 6 +-
4 files changed, 39 insertions(+), 115 deletions(-)

diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
index 186cbab..a3376731 100644
--- a/drivers/virtio/virtio_pci_common.c
+++ b/drivers/virtio/virtio_pci_common.c
@@ -62,16 +62,13 @@ static irqreturn_t vp_config_changed(int irq, void *opaque)
static irqreturn_t vp_vring_interrupt(int irq, void *opaque)
{
struct virtio_pci_device *vp_dev = opaque;
- struct virtio_pci_vq_info *info;
irqreturn_t ret = IRQ_NONE;
- unsigned long flags;
+ struct virtqueue *vq;

- spin_lock_irqsave(&vp_dev->lock, flags);
- list_for_each_entry(info, &vp_dev->virtqueues, node) {
- if (vring_interrupt(irq, info->vq) == IRQ_HANDLED)
+ list_for_each_entry(vq, &vp_dev->vdev.vqs, list) {
+ if (vq->callback && vring_interrupt(irq, vq) == IRQ_HANDLED)
ret = IRQ_HANDLED;
}
- spin_unlock_irqrestore(&vp_dev->lock, flags);

return ret;
}
@@ -167,55 +164,6 @@ static int vp_request_msix_vectors(struct virtio_device *vdev, int nvectors,
return err;
}

-static struct virtqueue *vp_setup_vq(struct virtio_device *vdev, unsigned index,
- void (*callback)(struct virtqueue *vq),
- const char *name,
- u16 msix_vec)
-{
- struct virtio_pci_device *vp_dev = to_vp_device(vdev);
- struct virtio_pci_vq_info *info = kmalloc(sizeof *info, GFP_KERNEL);
- struct virtqueue *vq;
- unsigned long flags;
-
- /* fill out our structure that represents an active queue */
- if (!info)
- return ERR_PTR(-ENOMEM);
-
- vq = vp_dev->setup_vq(vp_dev, info, index, callback, name, msix_vec);
- if (IS_ERR(vq))
- goto out_info;
-
- info->vq = vq;
- if (callback) {
- spin_lock_irqsave(&vp_dev->lock, flags);
- list_add(&info->node, &vp_dev->virtqueues);
- spin_unlock_irqrestore(&vp_dev->lock, flags);
- } else {
- INIT_LIST_HEAD(&info->node);
- }
-
- vp_dev->vqs[index] = info;
- return vq;
-
-out_info:
- kfree(info);
- return vq;
-}
-
-static void vp_del_vq(struct virtqueue *vq)
-{
- struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
- struct virtio_pci_vq_info *info = vp_dev->vqs[vq->index];
- unsigned long flags;
-
- spin_lock_irqsave(&vp_dev->lock, flags);
- list_del(&info->node);
- spin_unlock_irqrestore(&vp_dev->lock, flags);
-
- vp_dev->del_vq(info);
- kfree(info);
-}
-
/* the config->del_vqs() implementation */
void vp_del_vqs(struct virtio_device *vdev)
{
@@ -224,16 +172,15 @@ void vp_del_vqs(struct virtio_device *vdev)
int i;

list_for_each_entry_safe(vq, n, &vdev->vqs, list) {
- if (vp_dev->per_vq_vectors) {
- int v = vp_dev->vqs[vq->index]->msix_vector;
+ if (vp_dev->msix_vector_map) {
+ int v = vp_dev->msix_vector_map[vq->index];

if (v != VIRTIO_MSI_NO_VECTOR)
free_irq(pci_irq_vector(vp_dev->pci_dev, v),
vq);
}
- vp_del_vq(vq);
+ vp_dev->del_vq(vq);
}
- vp_dev->per_vq_vectors = false;

if (vp_dev->intx_enabled) {
free_irq(vp_dev->pci_dev->irq, vp_dev);
@@ -261,8 +208,8 @@ void vp_del_vqs(struct virtio_device *vdev)
vp_dev->msix_names = NULL;
kfree(vp_dev->msix_affinity_masks);
vp_dev->msix_affinity_masks = NULL;
- kfree(vp_dev->vqs);
- vp_dev->vqs = NULL;
+ kfree(vp_dev->msix_vector_map);
+ vp_dev->msix_vector_map = NULL;
}

static int vp_find_vqs_msix(struct virtio_device *vdev, unsigned nvqs,
@@ -275,10 +222,6 @@ static int vp_find_vqs_msix(struct virtio_device *vdev, unsigned nvqs,
u16 msix_vec;
int i, err, nvectors, allocated_vectors;

- vp_dev->vqs = kcalloc(nvqs, sizeof(*vp_dev->vqs), GFP_KERNEL);
- if (!vp_dev->vqs)
- return -ENOMEM;
-
if (per_vq_vectors) {
/* Best option: one for change interrupt, one per vq. */
nvectors = 1;
@@ -294,7 +237,13 @@ static int vp_find_vqs_msix(struct virtio_device *vdev, unsigned nvqs,
if (err)
goto error_find;

- vp_dev->per_vq_vectors = per_vq_vectors;
+ if (per_vq_vectors) {
+ vp_dev->msix_vector_map = kmalloc_array(nvqs,
+ sizeof(*vp_dev->msix_vector_map), GFP_KERNEL);
+ if (!vp_dev->msix_vector_map)
+ goto error_find;
+ }
+
allocated_vectors = vp_dev->msix_used_vectors;
for (i = 0; i < nvqs; ++i) {
if (!names[i]) {
@@ -304,19 +253,25 @@ static int vp_find_vqs_msix(struct virtio_device *vdev, unsigned nvqs,

if (!callbacks[i])
msix_vec = VIRTIO_MSI_NO_VECTOR;
- else if (vp_dev->per_vq_vectors)
+ else if (per_vq_vectors)
msix_vec = allocated_vectors++;
else
msix_vec = VP_MSIX_VQ_VECTOR;
- vqs[i] = vp_setup_vq(vdev, i, callbacks[i], names[i], msix_vec);
+ vqs[i] = vp_dev->setup_vq(vp_dev, i, callbacks[i], names[i],
+ msix_vec);
if (IS_ERR(vqs[i])) {
err = PTR_ERR(vqs[i]);
goto error_find;
}

- if (!vp_dev->per_vq_vectors || msix_vec == VIRTIO_MSI_NO_VECTOR)
+ if (!per_vq_vectors)
continue;

+ if (msix_vec == VIRTIO_MSI_NO_VECTOR) {
+ vp_dev->msix_vector_map[i] = VIRTIO_MSI_NO_VECTOR;
+ continue;
+ }
+
/* allocate per-vq irq if available and necessary */
snprintf(vp_dev->msix_names[msix_vec],
sizeof *vp_dev->msix_names,
@@ -326,8 +281,12 @@ static int vp_find_vqs_msix(struct virtio_device *vdev, unsigned nvqs,
vring_interrupt, 0,
vp_dev->msix_names[msix_vec],
vqs[i]);
- if (err)
+ if (err) {
+ /* don't free this irq on error */
+ vp_dev->msix_vector_map[i] = VIRTIO_MSI_NO_VECTOR;
goto error_find;
+ }
+ vp_dev->msix_vector_map[i] = msix_vec;
}
return 0;

@@ -343,23 +302,18 @@ static int vp_find_vqs_intx(struct virtio_device *vdev, unsigned nvqs,
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
int i, err;

- vp_dev->vqs = kcalloc(nvqs, sizeof(*vp_dev->vqs), GFP_KERNEL);
- if (!vp_dev->vqs)
- return -ENOMEM;
-
err = request_irq(vp_dev->pci_dev->irq, vp_interrupt, IRQF_SHARED,
dev_name(&vdev->dev), vp_dev);
if (err)
goto out_del_vqs;

vp_dev->intx_enabled = 1;
- vp_dev->per_vq_vectors = false;
for (i = 0; i < nvqs; ++i) {
if (!names[i]) {
vqs[i] = NULL;
continue;
}
- vqs[i] = vp_setup_vq(vdev, i, callbacks[i], names[i],
+ vqs[i] = vp_dev->setup_vq(vp_dev, i, callbacks[i], names[i],
VIRTIO_MSI_NO_VECTOR);
if (IS_ERR(vqs[i])) {
err = PTR_ERR(vqs[i]);
@@ -409,16 +363,15 @@ int vp_set_vq_affinity(struct virtqueue *vq, int cpu)
{
struct virtio_device *vdev = vq->vdev;
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
- struct virtio_pci_vq_info *info = vp_dev->vqs[vq->index];
- struct cpumask *mask;
- unsigned int irq;

if (!vq->callback)
return -EINVAL;

if (vp_dev->msix_enabled) {
- mask = vp_dev->msix_affinity_masks[info->msix_vector];
- irq = pci_irq_vector(vp_dev->pci_dev, info->msix_vector);
+ int vec = vp_dev->msix_vector_map[vq->index];
+ struct cpumask *mask = vp_dev->msix_affinity_masks[vec];
+ unsigned int irq = pci_irq_vector(vp_dev->pci_dev, vec);
+
if (cpu == -1)
irq_set_affinity_hint(irq, NULL);
else {
@@ -498,8 +451,6 @@ static int virtio_pci_probe(struct pci_dev *pci_dev,
vp_dev->vdev.dev.parent = &pci_dev->dev;
vp_dev->vdev.dev.release = virtio_pci_release_dev;
vp_dev->pci_dev = pci_dev;
- INIT_LIST_HEAD(&vp_dev->virtqueues);
- spin_lock_init(&vp_dev->lock);

/* enable the device */
rc = pci_enable_device(pci_dev);
diff --git a/drivers/virtio/virtio_pci_common.h b/drivers/virtio/virtio_pci_common.h
index b2f6662..2038887 100644
--- a/drivers/virtio/virtio_pci_common.h
+++ b/drivers/virtio/virtio_pci_common.h
@@ -31,17 +31,6 @@
#include <linux/highmem.h>
#include <linux/spinlock.h>

-struct virtio_pci_vq_info {
- /* the actual virtqueue */
- struct virtqueue *vq;
-
- /* the list node for the virtqueues list */
- struct list_head node;
-
- /* MSI-X vector (or none) */
- unsigned msix_vector;
-};
-
/* Our device structure */
struct virtio_pci_device {
struct virtio_device vdev;
@@ -75,13 +64,6 @@ struct virtio_pci_device {
/* the IO mapping for the PCI config space */
void __iomem *ioaddr;

- /* a list of queues so we can dispatch IRQs */
- spinlock_t lock;
- struct list_head virtqueues;
-
- /* array of all queues for house-keeping */
- struct virtio_pci_vq_info **vqs;
-
/* MSI-X support */
int msix_enabled;
int intx_enabled;
@@ -94,16 +76,15 @@ struct virtio_pci_device {
/* Vectors allocated, excluding per-vq vectors if any */
unsigned msix_used_vectors;

- /* Whether we have vector per vq */
- bool per_vq_vectors;
+ /* Map of per-VQ MSI-X vectors, may be NULL */
+ unsigned *msix_vector_map;

struct virtqueue *(*setup_vq)(struct virtio_pci_device *vp_dev,
- struct virtio_pci_vq_info *info,
unsigned idx,
void (*callback)(struct virtqueue *vq),
const char *name,
u16 msix_vec);
- void (*del_vq)(struct virtio_pci_vq_info *info);
+ void (*del_vq)(struct virtqueue *vq);

u16 (*config_vector)(struct virtio_pci_device *vp_dev, u16 vector);
};
diff --git a/drivers/virtio/virtio_pci_legacy.c b/drivers/virtio/virtio_pci_legacy.c
index 6d9e517..47292da 100644
--- a/drivers/virtio/virtio_pci_legacy.c
+++ b/drivers/virtio/virtio_pci_legacy.c
@@ -112,7 +112,6 @@ static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
}

static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
- struct virtio_pci_vq_info *info,
unsigned index,
void (*callback)(struct virtqueue *vq),
const char *name,
@@ -130,8 +129,6 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
if (!num || ioread32(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN))
return ERR_PTR(-ENOENT);

- info->msix_vector = msix_vec;
-
/* create the vring */
vq = vring_create_virtqueue(index, num,
VIRTIO_PCI_VRING_ALIGN, &vp_dev->vdev,
@@ -162,9 +159,8 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
return ERR_PTR(err);
}

-static void del_vq(struct virtio_pci_vq_info *info)
+static void del_vq(struct virtqueue *vq)
{
- struct virtqueue *vq = info->vq;
struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);

iowrite16(vq->index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL);
diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
index 4bf7ab3..00e6fc1 100644
--- a/drivers/virtio/virtio_pci_modern.c
+++ b/drivers/virtio/virtio_pci_modern.c
@@ -293,7 +293,6 @@ static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
}

static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
- struct virtio_pci_vq_info *info,
unsigned index,
void (*callback)(struct virtqueue *vq),
const char *name,
@@ -323,8 +322,6 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
/* get offset of notification word for this vq */
off = vp_ioread16(&cfg->queue_notify_off);

- info->msix_vector = msix_vec;
-
/* create the vring */
vq = vring_create_virtqueue(index, num,
SMP_CACHE_BYTES, &vp_dev->vdev,
@@ -409,9 +406,8 @@ static int vp_modern_find_vqs(struct virtio_device *vdev, unsigned nvqs,
return 0;
}

-static void del_vq(struct virtio_pci_vq_info *info)
+static void del_vq(struct virtqueue *vq)
{
- struct virtqueue *vq = info->vq;
struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);

vp_iowrite16(vq->index, &vp_dev->common->queue_select);
--
2.1.4