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Message-ID: <20240510232128.1105145-6-almasrymina@google.com>
Date: Fri, 10 May 2024 16:21:16 -0700
From: Mina Almasry <almasrymina@...gle.com>
To: netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-doc@...r.kernel.org, linux-alpha@...r.kernel.org,
linux-mips@...r.kernel.org, linux-parisc@...r.kernel.org,
sparclinux@...r.kernel.org, linux-trace-kernel@...r.kernel.org,
linux-arch@...r.kernel.org, bpf@...r.kernel.org,
linux-kselftest@...r.kernel.org, linux-media@...r.kernel.org,
dri-devel@...ts.freedesktop.org
Cc: Mina Almasry <almasrymina@...gle.com>, Donald Hunter <donald.hunter@...il.com>,
Jakub Kicinski <kuba@...nel.org>, "David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>, Paolo Abeni <pabeni@...hat.com>,
Jonathan Corbet <corbet@....net>, Richard Henderson <richard.henderson@...aro.org>,
Ivan Kokshaysky <ink@...assic.park.msu.ru>, Matt Turner <mattst88@...il.com>,
Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
"James E.J. Bottomley" <James.Bottomley@...senPartnership.com>, Helge Deller <deller@....de>,
Andreas Larsson <andreas@...sler.com>, Jesper Dangaard Brouer <hawk@...nel.org>,
Ilias Apalodimas <ilias.apalodimas@...aro.org>, Steven Rostedt <rostedt@...dmis.org>,
Masami Hiramatsu <mhiramat@...nel.org>, Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
Arnd Bergmann <arnd@...db.de>, Alexei Starovoitov <ast@...nel.org>, Daniel Borkmann <daniel@...earbox.net>,
Andrii Nakryiko <andrii@...nel.org>, Martin KaFai Lau <martin.lau@...ux.dev>,
Eduard Zingerman <eddyz87@...il.com>, Song Liu <song@...nel.org>,
Yonghong Song <yonghong.song@...ux.dev>, John Fastabend <john.fastabend@...il.com>,
KP Singh <kpsingh@...nel.org>, Stanislav Fomichev <sdf@...gle.com>, Hao Luo <haoluo@...gle.com>,
Jiri Olsa <jolsa@...nel.org>, Steffen Klassert <steffen.klassert@...unet.com>,
Herbert Xu <herbert@...dor.apana.org.au>, David Ahern <dsahern@...nel.org>,
Willem de Bruijn <willemdebruijn.kernel@...il.com>, Shuah Khan <shuah@...nel.org>,
Sumit Semwal <sumit.semwal@...aro.org>,
"Christian König" <christian.koenig@....com>, Pavel Begunkov <asml.silence@...il.com>,
David Wei <dw@...idwei.uk>, Jason Gunthorpe <jgg@...pe.ca>, Yunsheng Lin <linyunsheng@...wei.com>,
Shailend Chand <shailend@...gle.com>, Harshitha Ramamurthy <hramamurthy@...gle.com>,
Shakeel Butt <shakeel.butt@...ux.dev>, Jeroen de Borst <jeroendb@...gle.com>,
Praveen Kaligineedi <pkaligineedi@...gle.com>, Willem de Bruijn <willemb@...gle.com>,
Kaiyuan Zhang <kaiyuanz@...gle.com>
Subject: [PATCH net-next v9 05/14] netdev: netdevice devmem allocator
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 <willemb@...gle.com>
Signed-off-by: Kaiyuan Zhang <kaiyuanz@...gle.com>
Signed-off-by: Mina Almasry <almasrymina@...gle.com>
---
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 | 40 ++++++++++++++++++++++++++++++++++++++++
net/core/devmem.c | 36 ++++++++++++++++++++++++++++++++++++
3 files changed, 89 insertions(+)
diff --git a/include/net/devmem.h b/include/net/devmem.h
index fa03bdabdffd9..cd3186f5d1fbd 100644
--- a/include/net/devmem.h
+++ b/include/net/devmem.h
@@ -68,7 +68,20 @@ int net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd,
void net_devmem_unbind_dmabuf(struct net_devmem_dmabuf_binding *binding);
int net_devmem_bind_dmabuf_to_queue(struct net_device *dev, u32 rxq_idx,
struct net_devmem_dmabuf_binding *binding);
+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 72e932a1a9489..33014370a8858 100644
--- a/include/net/netmem.h
+++ b/include/net/netmem.h
@@ -14,8 +14,48 @@
struct net_iov {
struct dmabuf_genpool_chunk_owner *owner;
+ unsigned long dma_addr;
};
+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;
+}
+
+/* This returns the absolute dma_addr_t calculated from
+ * net_iov_owner(niov)->owner->base_dma_addr, not the page_pool-owned
+ * niov->dma_addr.
+ *
+ * The absolute dma_addr_t is a dma_addr_t that is always uncompressed.
+ *
+ * The page_pool-owner niov->dma_addr is the absolute dma_addr compressed into
+ * an unsigned long. Special handling is done when the unsigned long is 32-bit
+ * but the dma_addr_t is 64-bit.
+ *
+ * In general code looking for the dma_addr_t should use net_iov_dma_addr(),
+ * while page_pool code looking for the unsigned long dma_addr which mirrors
+ * the field in struct page should use niov->dma_addr.
+ */
+static inline dma_addr_t net_iov_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);
+}
+
+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 d82f92d7cf9ce..1f90e23a81441 100644
--- a/net/core/devmem.c
+++ b/net/core/devmem.c
@@ -54,6 +54,42 @@ 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];
+
+ niov->dma_addr = 0;
+
+ net_devmem_dmabuf_binding_get(binding);
+
+ 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_iov_dma_addr(niov);
+
+ if (gen_pool_has_addr(binding->chunk_pool, dma_addr, PAGE_SIZE))
+ gen_pool_free(binding->chunk_pool, dma_addr, PAGE_SIZE);
+
+ net_devmem_dmabuf_binding_put(binding);
+}
+
/* Protected by rtnl_lock() */
static DEFINE_XARRAY_FLAGS(net_devmem_dmabuf_bindings, XA_FLAGS_ALLOC1);
--
2.45.0.118.g7fe29c98d7-goog
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