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path: root/drivers/pci/p2pdma.c
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Diffstat (limited to 'drivers/pci/p2pdma.c')
-rw-r--r--drivers/pci/p2pdma.c109
1 files changed, 53 insertions, 56 deletions
diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
index 742928d0053e..234476226529 100644
--- a/drivers/pci/p2pdma.c
+++ b/drivers/pci/p2pdma.c
@@ -18,10 +18,9 @@
#include <linux/percpu-refcount.h>
#include <linux/random.h>
#include <linux/seq_buf.h>
+#include <linux/iommu.h>
struct pci_p2pdma {
- struct percpu_ref devmap_ref;
- struct completion devmap_ref_done;
struct gen_pool *pool;
bool p2pmem_published;
};
@@ -74,41 +73,20 @@ static const struct attribute_group p2pmem_group = {
.name = "p2pmem",
};
-static void pci_p2pdma_percpu_release(struct percpu_ref *ref)
-{
- struct pci_p2pdma *p2p =
- container_of(ref, struct pci_p2pdma, devmap_ref);
-
- complete_all(&p2p->devmap_ref_done);
-}
-
-static void pci_p2pdma_percpu_kill(struct percpu_ref *ref)
-{
- /*
- * pci_p2pdma_add_resource() may be called multiple times
- * by a driver and may register the percpu_kill devm action multiple
- * times. We only want the first action to actually kill the
- * percpu_ref.
- */
- if (percpu_ref_is_dying(ref))
- return;
-
- percpu_ref_kill(ref);
-}
-
static void pci_p2pdma_release(void *data)
{
struct pci_dev *pdev = data;
+ struct pci_p2pdma *p2pdma = pdev->p2pdma;
- if (!pdev->p2pdma)
+ if (!p2pdma)
return;
- wait_for_completion(&pdev->p2pdma->devmap_ref_done);
- percpu_ref_exit(&pdev->p2pdma->devmap_ref);
+ /* Flush and disable pci_alloc_p2p_mem() */
+ pdev->p2pdma = NULL;
+ synchronize_rcu();
- gen_pool_destroy(pdev->p2pdma->pool);
+ gen_pool_destroy(p2pdma->pool);
sysfs_remove_group(&pdev->dev.kobj, &p2pmem_group);
- pdev->p2pdma = NULL;
}
static int pci_p2pdma_setup(struct pci_dev *pdev)
@@ -124,12 +102,6 @@ static int pci_p2pdma_setup(struct pci_dev *pdev)
if (!p2p->pool)
goto out;
- init_completion(&p2p->devmap_ref_done);
- error = percpu_ref_init(&p2p->devmap_ref,
- pci_p2pdma_percpu_release, 0, GFP_KERNEL);
- if (error)
- goto out_pool_destroy;
-
error = devm_add_action_or_reset(&pdev->dev, pci_p2pdma_release, pdev);
if (error)
goto out_pool_destroy;
@@ -188,15 +160,12 @@ int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar, size_t size,
pgmap = devm_kzalloc(&pdev->dev, sizeof(*pgmap), GFP_KERNEL);
if (!pgmap)
return -ENOMEM;
-
pgmap->res.start = pci_resource_start(pdev, bar) + offset;
pgmap->res.end = pgmap->res.start + size - 1;
pgmap->res.flags = pci_resource_flags(pdev, bar);
- pgmap->ref = &pdev->p2pdma->devmap_ref;
pgmap->type = MEMORY_DEVICE_PCI_P2PDMA;
pgmap->pci_p2pdma_bus_offset = pci_bus_address(pdev, bar) -
pci_resource_start(pdev, bar);
- pgmap->kill = pci_p2pdma_percpu_kill;
addr = devm_memremap_pages(&pdev->dev, pgmap);
if (IS_ERR(addr)) {
@@ -204,17 +173,20 @@ int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar, size_t size,
goto pgmap_free;
}
- error = gen_pool_add_virt(pdev->p2pdma->pool, (unsigned long)addr,
+ error = gen_pool_add_owner(pdev->p2pdma->pool, (unsigned long)addr,
pci_bus_address(pdev, bar) + offset,
- resource_size(&pgmap->res), dev_to_node(&pdev->dev));
+ resource_size(&pgmap->res), dev_to_node(&pdev->dev),
+ pgmap->ref);
if (error)
- goto pgmap_free;
+ goto pages_free;
pci_info(pdev, "added peer-to-peer DMA memory %pR\n",
&pgmap->res);
return 0;
+pages_free:
+ devm_memunmap_pages(&pdev->dev, pgmap);
pgmap_free:
devm_kfree(&pdev->dev, pgmap);
return error;
@@ -223,7 +195,7 @@ EXPORT_SYMBOL_GPL(pci_p2pdma_add_resource);
/*
* Note this function returns the parent PCI device with a
- * reference taken. It is the caller's responsibily to drop
+ * reference taken. It is the caller's responsibility to drop
* the reference.
*/
static struct pci_dev *find_parent_pci_dev(struct device *dev)
@@ -284,6 +256,9 @@ static bool root_complex_whitelist(struct pci_dev *dev)
struct pci_dev *root = pci_get_slot(host->bus, PCI_DEVFN(0, 0));
unsigned short vendor, device;
+ if (iommu_present(dev->dev.bus))
+ return false;
+
if (!root)
return false;
@@ -380,7 +355,7 @@ static int upstream_bridge_distance(struct pci_dev *provider,
/*
* Allow the connection if both devices are on a whitelisted root
- * complex, but add an arbitary large value to the distance.
+ * complex, but add an arbitrary large value to the distance.
*/
if (root_complex_whitelist(provider) &&
root_complex_whitelist(client))
@@ -439,7 +414,7 @@ static int upstream_bridge_distance_warn(struct pci_dev *provider,
}
/**
- * pci_p2pdma_distance_many - Determive the cumulative distance between
+ * pci_p2pdma_distance_many - Determine the cumulative distance between
* a p2pdma provider and the clients in use.
* @provider: p2pdma provider to check against the client list
* @clients: array of devices to check (NULL-terminated)
@@ -468,6 +443,14 @@ int pci_p2pdma_distance_many(struct pci_dev *provider, struct device **clients,
return -1;
for (i = 0; i < num_clients; i++) {
+ if (IS_ENABLED(CONFIG_DMA_VIRT_OPS) &&
+ clients[i]->dma_ops == &dma_virt_ops) {
+ if (verbose)
+ dev_warn(clients[i],
+ "cannot be used for peer-to-peer DMA because the driver makes use of dma_virt_ops\n");
+ return -1;
+ }
+
pci_client = find_parent_pci_dev(clients[i]);
if (!pci_client) {
if (verbose)
@@ -585,19 +568,30 @@ EXPORT_SYMBOL_GPL(pci_p2pmem_find_many);
*/
void *pci_alloc_p2pmem(struct pci_dev *pdev, size_t size)
{
- void *ret;
+ void *ret = NULL;
+ struct percpu_ref *ref;
+ /*
+ * Pairs with synchronize_rcu() in pci_p2pdma_release() to
+ * ensure pdev->p2pdma is non-NULL for the duration of the
+ * read-lock.
+ */
+ rcu_read_lock();
if (unlikely(!pdev->p2pdma))
- return NULL;
-
- if (unlikely(!percpu_ref_tryget_live(&pdev->p2pdma->devmap_ref)))
- return NULL;
-
- ret = (void *)gen_pool_alloc(pdev->p2pdma->pool, size);
+ goto out;
- if (unlikely(!ret))
- percpu_ref_put(&pdev->p2pdma->devmap_ref);
+ ret = (void *)gen_pool_alloc_owner(pdev->p2pdma->pool, size,
+ (void **) &ref);
+ if (!ret)
+ goto out;
+ if (unlikely(!percpu_ref_tryget_live(ref))) {
+ gen_pool_free(pdev->p2pdma->pool, (unsigned long) ret, size);
+ ret = NULL;
+ goto out;
+ }
+out:
+ rcu_read_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(pci_alloc_p2pmem);
@@ -610,8 +604,11 @@ EXPORT_SYMBOL_GPL(pci_alloc_p2pmem);
*/
void pci_free_p2pmem(struct pci_dev *pdev, void *addr, size_t size)
{
- gen_pool_free(pdev->p2pdma->pool, (uintptr_t)addr, size);
- percpu_ref_put(&pdev->p2pdma->devmap_ref);
+ struct percpu_ref *ref;
+
+ gen_pool_free_owner(pdev->p2pdma->pool, (uintptr_t)addr, size,
+ (void **) &ref);
+ percpu_ref_put(ref);
}
EXPORT_SYMBOL_GPL(pci_free_p2pmem);
@@ -732,7 +729,7 @@ int pci_p2pdma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
* p2pdma mappings are not compatible with devices that use
* dma_virt_ops. If the upper layers do the right thing
* this should never happen because it will be prevented
- * by the check in pci_p2pdma_add_client()
+ * by the check in pci_p2pdma_distance_many()
*/
if (WARN_ON_ONCE(IS_ENABLED(CONFIG_DMA_VIRT_OPS) &&
dev->dma_ops == &dma_virt_ops))
generated by cgit v1.2.3-55-g7522 (git 2.39.0) at 2024-06-12 11:45:54 +0200