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Fri, 11 Sep 2026 08:45:58 -0700 (PDT) Received: from localhost ([2a03:2880:2ff:48::]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-86b2a1b827esm1318332b3a.51.2026.09.11.08.45.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 11 Sep 2026 08:45:58 -0700 (PDT) From: Stanislav Fomichev X-Google-Original-From: Stanislav Fomichev To: netdev@vger.kernel.org Cc: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, sdf@fomichev.me, bobbyeshleman@meta.com, almasrymina@google.com, linux-kernel@vger.kernel.org Subject: [PATCH net-next v2 2/3] net: devmem: embed net_iov_area in binding Date: Fri, 11 Sep 2026 08:45:54 -0700 Message-ID: <20260911154555.739041-3-sdf@fomichev.me> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260911154555.739041-1-sdf@fomichev.me> References: <20260911154555.739041-1-sdf@fomichev.me> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit After replacing the gen_pool with a binding-level freelist, devmem no longer needs a separate chunk owner object. There is only one net_iov_area for the binding, so store it directly in struct net_devmem_dmabuf_binding. Derive the binding from net_iov_owner() with container_of(), matching the pattern used by io_uring zcrx. This removes the leftover dmabuf_genpool_chunk_owner wrapper and its allocation/free path. Signed-off-by: Stanislav Fomichev --- net/core/devmem.c | 41 ++++++++++------------------------------- net/core/devmem.h | 26 +++++++------------------- 2 files changed, 17 insertions(+), 50 deletions(-) diff --git a/net/core/devmem.c b/net/core/devmem.c index 4883eb7f3a95..7949f8425bcd 100644 --- a/net/core/devmem.c +++ b/net/core/devmem.c @@ -29,15 +29,6 @@ static DEFINE_XARRAY_FLAGS(net_devmem_dmabuf_bindings, XA_FLAGS_ALLOC1); static const struct memory_provider_ops dmabuf_devmem_ops; -static void -net_devmem_dmabuf_free_chunk_owner(struct dmabuf_genpool_chunk_owner *owner) -{ - if (owner) { - kvfree(owner->area.niovs); - kfree(owner); - } -} - static void net_devmem_dmabuf_binding_release(struct percpu_ref *ref) { struct net_devmem_dmabuf_binding *binding = @@ -55,7 +46,7 @@ void __net_devmem_dmabuf_binding_free(struct work_struct *wq) "can't destroy dmabuf binding. total=%zu, free=%zu", binding->total_niovs, binding->free_count); - net_devmem_dmabuf_free_chunk_owner(binding->chunk_owner); + kvfree(binding->area.niovs); dma_buf_unmap_attachment_unlocked(binding->attachment, binding->sgt, binding->direction); dma_buf_detach(binding->dmabuf, binding->attachment); @@ -271,23 +262,14 @@ net_devmem_bind_dmabuf(struct net_device *dev, void *vdev, } binding->total_niovs = total_niovs; - owner = kzalloc_node(sizeof(*owner), GFP_KERNEL, - dev_to_node(&dev->dev)); - if (!owner) { + binding->area.num_niovs = total_niovs; + binding->area.niovs = kvmalloc_objs(*binding->area.niovs, + binding->area.num_niovs); + if (!binding->area.niovs) { err = -ENOMEM; goto err_free_freelist; } - owner->area.num_niovs = total_niovs; - owner->binding = binding; - owner->area.niovs = kvmalloc_objs(*owner->area.niovs, - owner->area.num_niovs); - if (!owner->area.niovs) { - err = -ENOMEM; - goto err_free_owner; - } - binding->chunk_owner = owner; - niov_idx = 0; for_each_sgtable_dma_sg(binding->sgt, sg, sg_idx) { dma_addr_t dma_addr = sg_dma_address(sg); @@ -296,8 +278,8 @@ net_devmem_bind_dmabuf(struct net_device *dev, void *vdev, size_t nr_niovs = len >> niov_shift; for (i = 0; i < nr_niovs; i++, niov_idx++) { - niov = &owner->area.niovs[niov_idx]; - net_iov_init(niov, &owner->area, NET_IOV_DMABUF); + niov = &binding->area.niovs[niov_idx]; + net_iov_init(niov, &binding->area, NET_IOV_DMABUF); page_pool_set_dma_addr_netmem(net_iov_to_netmem(niov), dma_addr); if (direction == DMA_TO_DEVICE) @@ -311,17 +293,14 @@ net_devmem_bind_dmabuf(struct net_device *dev, void *vdev, binding, xa_limit_32b, &id_alloc_next, GFP_KERNEL); if (err < 0) - goto err_free_chunk_owner; + goto err_free_niovs; list_add(&binding->list, &priv->bindings); return binding; -err_free_chunk_owner: - net_devmem_dmabuf_free_chunk_owner(binding->chunk_owner); - goto err_free_freelist; -err_free_owner: - kfree(owner); +err_free_niovs: + kvfree(binding->area.niovs); err_free_freelist: kvfree(binding->freelist); err_tx_vec: diff --git a/net/core/devmem.h b/net/core/devmem.h index a5ee2d8d9169..20a3eb90ea7f 100644 --- a/net/core/devmem.h +++ b/net/core/devmem.h @@ -14,9 +14,9 @@ #include struct netlink_ext_ack; -struct dmabuf_genpool_chunk_owner; struct net_devmem_dmabuf_binding { + struct net_iov_area area; struct dma_buf *dmabuf; struct dma_buf_attachment *attachment; struct sg_table *sgt; @@ -27,7 +27,6 @@ struct net_devmem_dmabuf_binding { * dereferenced. */ void *vdev; - struct dmabuf_genpool_chunk_owner *chunk_owner; /* Protect dev */ struct mutex lock; @@ -83,11 +82,6 @@ struct net_devmem_dmabuf_binding { }; #if defined(CONFIG_NET_DEVMEM) -struct dmabuf_genpool_chunk_owner { - struct net_iov_area area; - struct net_devmem_dmabuf_binding *binding; -}; - void __net_devmem_dmabuf_binding_free(struct work_struct *wq); struct net_devmem_dmabuf_binding * net_devmem_bind_dmabuf(struct net_device *dev, void *vdev, @@ -102,18 +96,12 @@ 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); -static inline struct dmabuf_genpool_chunk_owner * -net_devmem_iov_to_chunk_owner(const struct net_iov *niov) -{ - struct net_iov_area *owner = net_iov_owner(niov); - - return container_of(owner, struct dmabuf_genpool_chunk_owner, area); -} - static inline struct net_devmem_dmabuf_binding * net_devmem_iov_binding(const struct net_iov *niov) { - return net_devmem_iov_to_chunk_owner(niov)->binding; + struct net_iov_area *owner = net_iov_owner(niov); + + return container_of(owner, struct net_devmem_dmabuf_binding, area); } static inline u32 net_devmem_iov_binding_id(const struct net_iov *niov) @@ -123,11 +111,11 @@ static inline u32 net_devmem_iov_binding_id(const struct net_iov *niov) static inline unsigned long net_iov_virtual_addr(const struct net_iov *niov) { - struct dmabuf_genpool_chunk_owner *co = - net_devmem_iov_to_chunk_owner(niov); + struct net_devmem_dmabuf_binding *binding = + net_devmem_iov_binding(niov); return net_iov_owner(niov)->base_virtual + - ((unsigned long)net_iov_idx(niov) << co->binding->niov_shift); + ((unsigned long)net_iov_idx(niov) << binding->niov_shift); } static inline bool -- 2.53.0-Meta