1*6094ea64SLeon Romanovsky // SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB 2*6094ea64SLeon Romanovsky /* Copyright (c) 2026, NVIDIA CORPORATION & AFFILIATES. */ 3*6094ea64SLeon Romanovsky 4*6094ea64SLeon Romanovsky #include <linux/export.h> 5*6094ea64SLeon Romanovsky #include <rdma/iter.h> 6*6094ea64SLeon Romanovsky 7*6094ea64SLeon Romanovsky void __rdma_block_iter_start(struct ib_block_iter *biter, 8*6094ea64SLeon Romanovsky struct scatterlist *sglist, unsigned int nents, 9*6094ea64SLeon Romanovsky unsigned long pgsz) 10*6094ea64SLeon Romanovsky { 11*6094ea64SLeon Romanovsky memset(biter, 0, sizeof(struct ib_block_iter)); 12*6094ea64SLeon Romanovsky biter->__sg = sglist; 13*6094ea64SLeon Romanovsky biter->__sg_nents = nents; 14*6094ea64SLeon Romanovsky 15*6094ea64SLeon Romanovsky /* Driver provides best block size to use */ 16*6094ea64SLeon Romanovsky biter->__pg_bit = __fls(pgsz); 17*6094ea64SLeon Romanovsky } 18*6094ea64SLeon Romanovsky EXPORT_SYMBOL(__rdma_block_iter_start); 19*6094ea64SLeon Romanovsky 20*6094ea64SLeon Romanovsky bool __rdma_block_iter_next(struct ib_block_iter *biter) 21*6094ea64SLeon Romanovsky { 22*6094ea64SLeon Romanovsky unsigned int block_offset; 23*6094ea64SLeon Romanovsky unsigned int delta; 24*6094ea64SLeon Romanovsky 25*6094ea64SLeon Romanovsky if (!biter->__sg_nents || !biter->__sg) 26*6094ea64SLeon Romanovsky return false; 27*6094ea64SLeon Romanovsky 28*6094ea64SLeon Romanovsky biter->__dma_addr = sg_dma_address(biter->__sg) + biter->__sg_advance; 29*6094ea64SLeon Romanovsky block_offset = biter->__dma_addr & (BIT_ULL(biter->__pg_bit) - 1); 30*6094ea64SLeon Romanovsky delta = BIT_ULL(biter->__pg_bit) - block_offset; 31*6094ea64SLeon Romanovsky 32*6094ea64SLeon Romanovsky while (biter->__sg_nents && biter->__sg && 33*6094ea64SLeon Romanovsky sg_dma_len(biter->__sg) - biter->__sg_advance <= delta) { 34*6094ea64SLeon Romanovsky delta -= sg_dma_len(biter->__sg) - biter->__sg_advance; 35*6094ea64SLeon Romanovsky biter->__sg_advance = 0; 36*6094ea64SLeon Romanovsky biter->__sg = sg_next(biter->__sg); 37*6094ea64SLeon Romanovsky biter->__sg_nents--; 38*6094ea64SLeon Romanovsky } 39*6094ea64SLeon Romanovsky biter->__sg_advance += delta; 40*6094ea64SLeon Romanovsky 41*6094ea64SLeon Romanovsky return true; 42*6094ea64SLeon Romanovsky } 43*6094ea64SLeon Romanovsky EXPORT_SYMBOL(__rdma_block_iter_next); 44