From a808273a495c657e33281b181fd7fcc2bb28f662 Mon Sep 17 00:00:00 2001 From: Shiraz Saleem Date: Mon, 6 May 2019 08:53:33 -0500 Subject: RDMA/verbs: Add a DMA iterator to return aligned contiguous memory blocks This helper iterates over a DMA-mapped SGL and returns contiguous memory blocks aligned to a HW supported page size. Suggested-by: Jason Gunthorpe Signed-off-by: Shiraz Saleem Signed-off-by: Jason Gunthorpe --- include/rdma/ib_verbs.h | 47 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) (limited to 'include/rdma/ib_verbs.h') diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h index 03b07ec6a34b..deb67b21ccb9 100644 --- a/include/rdma/ib_verbs.h +++ b/include/rdma/ib_verbs.h @@ -2726,6 +2726,21 @@ struct ib_client { u8 no_kverbs_req:1; }; +/* + * IB block DMA iterator + * + * Iterates the DMA-mapped SGL in contiguous memory blocks aligned + * to a HW supported page size. + */ +struct ib_block_iter { + /* internal states */ + struct scatterlist *__sg; /* sg holding the current aligned block */ + dma_addr_t __dma_addr; /* unaligned DMA address of this block */ + unsigned int __sg_nents; /* number of SG entries */ + unsigned int __sg_advance; /* number of bytes to advance in sg in next step */ + unsigned int __pg_bit; /* alignment of current block */ +}; + struct ib_device *_ib_alloc_device(size_t size); #define ib_alloc_device(drv_struct, member) \ container_of(_ib_alloc_device(sizeof(struct drv_struct) + \ @@ -2746,6 +2761,38 @@ void ib_unregister_device_queued(struct ib_device *ib_dev); int ib_register_client (struct ib_client *client); void ib_unregister_client(struct ib_client *client); +void __rdma_block_iter_start(struct ib_block_iter *biter, + struct scatterlist *sglist, + unsigned int nents, + unsigned long pgsz); +bool __rdma_block_iter_next(struct ib_block_iter *biter); + +/** + * rdma_block_iter_dma_address - get the aligned dma address of the current + * block held by the block iterator. + * @biter: block iterator holding the memory block + */ +static inline dma_addr_t +rdma_block_iter_dma_address(struct ib_block_iter *biter) +{ + return biter->__dma_addr & ~(BIT_ULL(biter->__pg_bit) - 1); +} + +/** + * rdma_for_each_block - iterate over contiguous memory blocks of the sg list + * @sglist: sglist to iterate over + * @biter: block iterator holding the memory block + * @nents: maximum number of sg entries to iterate over + * @pgsz: best HW supported page size to use + * + * Callers may use rdma_block_iter_dma_address() to get each + * blocks aligned DMA address. + */ +#define rdma_for_each_block(sglist, biter, nents, pgsz) \ + for (__rdma_block_iter_start(biter, sglist, nents, \ + pgsz); \ + __rdma_block_iter_next(biter);) + /** * ib_get_client_data - Get IB client context * @device:Device to get context for -- cgit v1.2.3-59-g8ed1b