diff options
Diffstat (limited to 'drivers/infiniband/core/umem.c')
-rw-r--r-- | drivers/infiniband/core/umem.c | 51 |
1 files changed, 51 insertions, 0 deletions
diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c index 23f7512cc7a8..145c31c530ae 100644 --- a/drivers/infiniband/core/umem.c +++ b/drivers/infiniband/core/umem.c @@ -131,6 +131,57 @@ static struct scatterlist *ib_umem_add_sg_table(struct scatterlist *sg, } /** + * ib_umem_find_best_pgsz - Find best HW page size to use for this MR + * + * @umem: umem struct + * @pgsz_bitmap: bitmap of HW supported page sizes + * @virt: IOVA + * + * This helper is intended for HW that support multiple page + * sizes but can do only a single page size in an MR. + * + * Returns 0 if the umem requires page sizes not supported by + * the driver to be mapped. Drivers always supporting PAGE_SIZE + * or smaller will never see a 0 result. + */ +unsigned long ib_umem_find_best_pgsz(struct ib_umem *umem, + unsigned long pgsz_bitmap, + unsigned long virt) +{ + struct scatterlist *sg; + unsigned int best_pg_bit; + unsigned long va, pgoff; + dma_addr_t mask; + int i; + + /* At minimum, drivers must support PAGE_SIZE or smaller */ + if (WARN_ON(!(pgsz_bitmap & GENMASK(PAGE_SHIFT, 0)))) + return 0; + + va = virt; + /* max page size not to exceed MR length */ + mask = roundup_pow_of_two(umem->length); + /* offset into first SGL */ + pgoff = umem->address & ~PAGE_MASK; + + for_each_sg(umem->sg_head.sgl, sg, umem->nmap, i) { + /* Walk SGL and reduce max page size if VA/PA bits differ + * for any address. + */ + mask |= (sg_dma_address(sg) + pgoff) ^ va; + if (i && i != (umem->nmap - 1)) + /* restrict by length as well for interior SGEs */ + mask |= sg_dma_len(sg); + va += sg_dma_len(sg) - pgoff; + pgoff = 0; + } + best_pg_bit = rdma_find_pg_bit(mask, pgsz_bitmap); + + return BIT_ULL(best_pg_bit); +} +EXPORT_SYMBOL(ib_umem_find_best_pgsz); + +/** * ib_umem_get - Pin and DMA map userspace memory. * * If access flags indicate ODP memory, avoid pinning. Instead, stores |