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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman Cc: michael.chan@broadcom.com, pavan.chebbi@broadcom.com, linux-kernel@vger.kernel.org, Joe Damato Subject: [RFC net-next 01/10] net: tso: Introduce tso_dma_map Date: Tue, 10 Mar 2026 14:21:49 -0700 Message-ID: <20260310212209.2263939-2-joe@dama.to> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260310212209.2263939-1-joe@dama.to> References: <20260310212209.2263939-1-joe@dama.to> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Add struct tso_dma_map to tso.h for tracking DMA addresses of mapped GSO payload data. The struct combines DMA mapping storage (linear_dma, frags[]) with iterator state (frag_idx, offset), allowing drivers to walk pre-mapped DMA regions linearly. Helpers to initialize and operate on this struct will be added in the next commit. Suggested-by: Jakub Kicinski Signed-off-by: Joe Damato --- include/net/tso.h | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) diff --git a/include/net/tso.h b/include/net/tso.h index e7e157ae0526..9a508e60ee19 100644 --- a/include/net/tso.h +++ b/include/net/tso.h @@ -3,6 +3,7 @@ #define _TSO_H =20 #include +#include #include =20 #define TSO_HEADER_SIZE 256 @@ -28,4 +29,40 @@ void tso_build_hdr(const struct sk_buff *skb, char *hdr,= struct tso_t *tso, void tso_build_data(const struct sk_buff *skb, struct tso_t *tso, int size= ); int tso_start(struct sk_buff *skb, struct tso_t *tso); =20 +/** + * struct tso_dma_map - DMA mapping state for GSO payload + * @dev: device used for DMA mapping + * @skb: the GSO skb being mapped + * @hdr_len: per-segment header length + * @frag_idx: current region (-1 =3D linear, 0..nr_frags-1 =3D frag) + * @offset: byte offset within current region + * @linear_dma: DMA address of the linear payload (after headers) + * @linear_len: length of the linear payload + * @nr_frags: number of frags successfully DMA-mapped + * @frags: per-frag DMA address and length + * + * Struct that DMA-maps the payload regions of a GSO skb + * (linear data + frags) upfront, then provides iteration to yield + * (dma_addr, chunk_len) pairs bounded by region boundaries. + * + * Drivers set dma_unmap_len on the first descriptor touching each DMA + * mapping; the completion path unmaps via per-descriptor dma_unmap_len. + */ +struct tso_dma_map { + struct device *dev; + const struct sk_buff *skb; + unsigned int hdr_len; + /* Iterator state */ + int frag_idx; + unsigned int offset; + /* Pre-mapped regions */ + dma_addr_t linear_dma; + unsigned int linear_len; + unsigned int nr_frags; + struct { + dma_addr_t dma; + unsigned int len; + } frags[MAX_SKB_FRAGS]; +}; + #endif /* _TSO_H */ --=20 2.52.0