Implement netdev devmem allocator. The allocator takes a given struct
netdev_dmabuf_binding as input and allocates net_iov from that
binding.
The allocation simply delegates to the binding's genpool for the
allocation logic and wraps the returned memory region in a net_iov
struct.
Signed-off-by: Willem de Bruijn <will...@google.com>
Signed-off-by: Kaiyuan Zhang <kaiyu...@google.com>
Signed-off-by: Mina Almasry <almasrym...@google.com>
Reviewed-by: Pavel Begunkov <asml.sile...@gmail.com>
Reviewed-by: Jakub Kicinski <k...@kernel.org>
---
v23:
- WARN_ON when we don't see the dma_addr in the gen_pool (Jakub)
v20:
- Removed dma_addr field in dmabuf_genpool_chunk_owner not used in this
patch (moved to later patch where it's used).
v19:
- Don't reset dma_addr on allocation/free (Jakub)
v17:
- Don't acquire a binding ref for every allocation (Jakub).
v11:
- Fix extraneous inline directive (Paolo)
v8:
- Rename netdev_dmabuf_binding -> net_devmem_dmabuf_binding to avoid
patch-by-patch build error.
- Move niov->pp_magic/pp/pp_ref_counter usage to later patch to avoid
patch-by-patch build error.
v7:
- netdev_ -> net_devmem_* naming (Yunsheng).
v6:
- Add comment on net_iov_dma_addr to explain why we don't use
niov->dma_addr (Pavel)
- Refactor new functions into net/core/devmem.c (Pavel)
v1:
- Rename devmem -> dmabuf (David).
---
include/net/devmem.h | 13 +++++++++++++
include/net/netmem.h | 17 +++++++++++++++++
net/core/devmem.c | 41 +++++++++++++++++++++++++++++++++++++++++
3 files changed, 71 insertions(+)
diff --git a/include/net/devmem.h b/include/net/devmem.h
index 3e406b6bfcf3..d315028c1499 100644
--- a/include/net/devmem.h
+++ b/include/net/devmem.h
@@ -73,7 +73,20 @@ int net_devmem_bind_dmabuf_to_queue(struct net_device *dev,
u32 rxq_idx,
struct net_devmem_dmabuf_binding *binding,
struct netlink_ext_ack *extack);
void dev_dmabuf_uninstall(struct net_device *dev);
+struct net_iov *
+net_devmem_alloc_dmabuf(struct net_devmem_dmabuf_binding *binding);
+void net_devmem_free_dmabuf(struct net_iov *ppiov);
#else
+static inline struct net_iov *
+net_devmem_alloc_dmabuf(struct net_devmem_dmabuf_binding *binding)
+{
+ return NULL;
+}
+
+static inline void net_devmem_free_dmabuf(struct net_iov *ppiov)
+{
+}
+
static inline void
__net_devmem_dmabuf_binding_free(struct net_devmem_dmabuf_binding *binding)
{
diff --git a/include/net/netmem.h b/include/net/netmem.h
index 41e96c2f94b5..0fbc0999091a 100644
--- a/include/net/netmem.h
+++ b/include/net/netmem.h
@@ -16,6 +16,23 @@ struct net_iov {
struct dmabuf_genpool_chunk_owner *owner;
};
+static inline struct dmabuf_genpool_chunk_owner *
+net_iov_owner(const struct net_iov *niov)
+{
+ return niov->owner;
+}
+
+static inline unsigned int net_iov_idx(const struct net_iov *niov)
+{
+ return niov - net_iov_owner(niov)->niovs;
+}
+
+static inline struct net_devmem_dmabuf_binding *
+net_iov_binding(const struct net_iov *niov)
+{
+ return net_iov_owner(niov)->binding;
+}
+
/* netmem */
/**
diff --git a/net/core/devmem.c b/net/core/devmem.c
index 3b8fa6a50147..ad222d108d37 100644
--- a/net/core/devmem.c
+++ b/net/core/devmem.c
@@ -33,6 +33,14 @@ static void net_devmem_dmabuf_free_chunk_owner(struct
gen_pool *genpool,
kfree(owner);
}
+static dma_addr_t net_devmem_get_dma_addr(const struct net_iov *niov)
+{
+ struct dmabuf_genpool_chunk_owner *owner = net_iov_owner(niov);
+
+ return owner->base_dma_addr +
+ ((dma_addr_t)net_iov_idx(niov) << PAGE_SHIFT);
+}
+
void __net_devmem_dmabuf_binding_free(struct net_devmem_dmabuf_binding
*binding)
{
size_t size, avail;
@@ -55,6 +63,39 @@ void __net_devmem_dmabuf_binding_free(struct
net_devmem_dmabuf_binding *binding)
kfree(binding);
}
+struct net_iov *
+net_devmem_alloc_dmabuf(struct net_devmem_dmabuf_binding *binding)
+{
+ struct dmabuf_genpool_chunk_owner *owner;
+ unsigned long dma_addr;
+ struct net_iov *niov;
+ ssize_t offset;
+ ssize_t index;
+
+ dma_addr = gen_pool_alloc_owner(binding->chunk_pool, PAGE_SIZE,
+ (void **)&owner);
+ if (!dma_addr)
+ return NULL;
+
+ offset = dma_addr - owner->base_dma_addr;
+ index = offset / PAGE_SIZE;
+ niov = &owner->niovs[index];
+
+ return niov;
+}
+
+void net_devmem_free_dmabuf(struct net_iov *niov)
+{
+ struct net_devmem_dmabuf_binding *binding = net_iov_binding(niov);
+ unsigned long dma_addr = net_devmem_get_dma_addr(niov);
+
+ if (WARN_ON(!gen_pool_has_addr(binding->chunk_pool, dma_addr,
+ PAGE_SIZE)))
+ return;
+
+ gen_pool_free(binding->chunk_pool, dma_addr, PAGE_SIZE);
+}
+
void net_devmem_unbind_dmabuf(struct net_devmem_dmabuf_binding *binding)
{
struct netdev_rx_queue *rxq;
--
2.46.0.469.g59c65b2a67-goog
