diff options
Diffstat (limited to 'include/net')
| -rw-r--r-- | include/net/tso.h | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/include/net/tso.h b/include/net/tso.h index e7e157ae0526..da82aabd1d48 100644 --- a/include/net/tso.h +++ b/include/net/tso.h @@ -3,6 +3,7 @@ #define _TSO_H #include <linux/skbuff.h> +#include <linux/dma-mapping.h> #include <net/ip.h> #define TSO_HEADER_SIZE 256 @@ -28,4 +29,103 @@ 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); +/** + * 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 + * @iova_state: DMA IOVA state (when IOMMU available) + * @iova_offset: global byte offset into IOVA range (IOVA path only) + * @total_len: total payload length + * @frag_idx: current region (-1 = linear, 0..nr_frags-1 = frag) + * @offset: byte offset within current region + * @linear_dma: DMA address of the linear payload + * @linear_len: length of the linear payload + * @nr_frags: number of frags successfully DMA-mapped + * @frags: per-frag DMA address and length + * + * DMA-maps the payload regions of a GSO skb (linear data + frags). + * Prefers the DMA IOVA API for a single contiguous mapping with one + * IOTLB sync; falls back to per-region dma_map_phys() otherwise. + */ +struct tso_dma_map { + struct device *dev; + const struct sk_buff *skb; + unsigned int hdr_len; + /* IOVA path */ + struct dma_iova_state iova_state; + size_t iova_offset; + size_t total_len; + /* Fallback path if IOVA path fails */ + int frag_idx; + unsigned int offset; + 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]; +}; + +/** + * struct tso_dma_map_completion_state - Completion-time cleanup state + * @iova_state: DMA IOVA state (when IOMMU available) + * @total_len: total payload length of the IOVA mapping + * + * Drivers store this on their SW ring at xmit time via + * tso_dma_map_completion_save(), then call tso_dma_map_complete() at + * completion time. + */ +struct tso_dma_map_completion_state { + struct dma_iova_state iova_state; + size_t total_len; +}; + +int tso_dma_map_init(struct tso_dma_map *map, struct device *dev, + const struct sk_buff *skb, unsigned int hdr_len); +void tso_dma_map_cleanup(struct tso_dma_map *map); +unsigned int tso_dma_map_count(struct tso_dma_map *map, unsigned int len); +bool tso_dma_map_next(struct tso_dma_map *map, dma_addr_t *addr, + unsigned int *chunk_len, unsigned int *mapping_len, + unsigned int seg_remaining); + +/** + * tso_dma_map_completion_save - save state needed for completion-time cleanup + * @map: the xmit-time DMA map + * @cstate: driver-owned storage that persists until completion + * + * Should be called at xmit time to update the completion state and later passed + * to tso_dma_map_complete(). + */ +static inline void +tso_dma_map_completion_save(const struct tso_dma_map *map, + struct tso_dma_map_completion_state *cstate) +{ + cstate->iova_state = map->iova_state; + cstate->total_len = map->total_len; +} + +/** + * tso_dma_map_complete - tear down mapping at completion time + * @dev: the device that owns the mapping + * @cstate: state saved by tso_dma_map_completion_save() + * + * Return: true if the IOVA path was used and the mapping has been + * destroyed; false if the fallback per-region path was used and the + * driver must unmap via its normal completion path. + */ +static inline bool +tso_dma_map_complete(struct device *dev, + struct tso_dma_map_completion_state *cstate) +{ + if (dma_use_iova(&cstate->iova_state)) { + dma_iova_destroy(dev, &cstate->iova_state, cstate->total_len, + DMA_TO_DEVICE, 0); + return true; + } + + return false; +} + #endif /* _TSO_H */ |