[rdma-next,v1,2/6] RDMA/umem: Add API to find best driver supported page size in an MR

Message ID	20190219145745.13476-3-shiraz.saleem@intel.com (mailing list archive)
State	Changes Requested
Delegated to:	Jason Gunthorpe
Headers	show Return-Path: <linux-rdma-owner@kernel.org> From: Shiraz Saleem <shiraz.saleem@intel.com> To: dledford@redhat.com, jgg@ziepe.ca Cc: linux-rdma@vger.kernel.org, Shiraz Saleem <shiraz.saleem@intel.com> Subject: [PATCH rdma-next v1 2/6] RDMA/umem: Add API to find best driver supported page size in an MR Date: Tue, 19 Feb 2019 08:57:41 -0600 Message-Id: <20190219145745.13476-3-shiraz.saleem@intel.com> In-Reply-To: <20190219145745.13476-1-shiraz.saleem@intel.com> References: <20190219145745.13476-1-shiraz.saleem@intel.com> Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk
Series	Add APIs to get contiguous memory blocks aligned to a HW supported page size \| expand [rdma-next,v1,0/6] Add APIs to get contiguous memory blocks aligned to a HW supported page size [rdma-next,v1,1/6] RDMA/umem: Combine contiguous PAGE_SIZE regions in SGEs [rdma-next,v1,2/6] RDMA/umem: Add API to find best driver supported page size in an MR [rdma-next,v1,3/6] RDMA/umem: Add API to return aligned memory blocks from SGL [rdma-next,v1,4/6] RDMA/i40iw: Use umem API to retrieve aligned DMA address [rdma-next,v1,5/6] RDMA/bnxt_re: Use umem APIs to retrieve aligned DMA address [rdma-next,v1,6/6] RDMA/umem: Remove hugetlb flag

diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c index e8611b7..d3b572e 100644 --- a/drivers/infiniband/core/umem.c +++ b/drivers/infiniband/core/umem.c @@ -125,6 +125,96 @@ struct scatterlist *ib_umem_add_sg_table(struct scatterlist *sg, } /** + * ib_umem_find_pg_bit - Find the page bit to use for phyaddr + * + * @phyaddr: Physical address after DMA translation + * @supported_pgsz: bitmask of HW supported page sizes + */ +static unsigned int ib_umem_find_pg_bit(unsigned long phyaddr, + unsigned long supported_pgsz) +{ + unsigned long num_zeroes; + unsigned long pgsz; + + /* Trailing zero bits in the address */ + num_zeroes = __ffs(phyaddr); + + /* Find page bit such that phyaddr is aligned to the highest supported + * HW page size + */ + pgsz = supported_pgsz & (BIT_ULL(num_zeroes + 1) - 1); + if (!pgsz) + return __ffs(supported_pgsz); + + return fls64(pgsz) - 1; +} + +/** + * ib_umem_find_single_pg_size - Find best HW page size to use for this MR + * @umem: umem struct + * @supported_pgsz: bitmask of HW supported page sizes + * @uvirt_addr: user-space virtual MR base address + * + * 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_single_pg_size(struct ib_umem *umem, + unsigned long supported_pgsz, + unsigned long uvirt_addr) +{ + struct scatterlist *sg; + unsigned int pg_bit_sg, min_pg_bit, best_pg_bit; + int i; + + if (WARN_ON(!(supported_pgsz & GENMASK(PAGE_SHIFT, 0)))) + return 0; + + min_pg_bit = __ffs(supported_pgsz); + best_pg_bit = fls64(supported_pgsz) - 1; + + for_each_sg(umem->sg_head.sgl, sg, umem->nmap, i) { + unsigned long dma_addr_start, dma_addr_end; + + dma_addr_start = sg_dma_address(sg); + dma_addr_end = sg_dma_address(sg) + sg_dma_len(sg); + if (!i) { + pg_bit_sg = ib_umem_find_pg_bit(dma_addr_end, supported_pgsz); + + /* The start offset of the MR into a first _large_ page + * should line up exactly for the user-space virtual buf + * and physical buffer, in order to upgrade the page bit + */ + if (pg_bit_sg > PAGE_SHIFT) { + unsigned int uvirt_pg_bit; + + uvirt_pg_bit = ib_umem_find_pg_bit(uvirt_addr + sg_dma_len(sg), + supported_pgsz); + pg_bit_sg = min_t(unsigned int, uvirt_pg_bit, pg_bit_sg); + } + } else if (i == (umem->nmap - 1)) { + /* last SGE: Does not matter if MR ends at an + * unaligned offset. + */ + pg_bit_sg = ib_umem_find_pg_bit(dma_addr_start, supported_pgsz); + } else { + pg_bit_sg = ib_umem_find_pg_bit(dma_addr_start, + supported_pgsz & (BIT_ULL(__ffs(sg_dma_len(sg)) + 1) - 1)); + } + + best_pg_bit = min_t(unsigned int, best_pg_bit, pg_bit_sg); + if (best_pg_bit == min_pg_bit) + break; + } + + return BIT_ULL(best_pg_bit); +} +EXPORT_SYMBOL(ib_umem_find_single_pg_size); + +/** * ib_umem_get - Pin and DMA map userspace memory. * * If access flags indicate ODP memory, avoid pinning. Instead, stores diff --git a/include/rdma/ib_umem.h b/include/rdma/ib_umem.h index 18407a4..4e186a3 100644 --- a/include/rdma/ib_umem.h +++ b/include/rdma/ib_umem.h @@ -88,6 +88,9 @@ struct ib_umem *ib_umem_get(struct ib_udata *udata, unsigned long addr, int ib_umem_page_count(struct ib_umem *umem); int ib_umem_copy_from(void *dst, struct ib_umem *umem, size_t offset, size_t length); +unsigned long ib_umem_find_single_pg_size(struct ib_umem *umem, + unsigned long supported_pgsz, + unsigned long uvirt_addr); #else /* CONFIG_INFINIBAND_USER_MEM */ @@ -105,6 +108,12 @@ static inline int ib_umem_copy_from(void *dst, struct ib_umem *umem, size_t offs size_t length) { return -EINVAL; } +static inline int ib_umem_find_single_pg_size(struct ib_umem *umem, + unsigned long supported_pgsz, + unsigned long uvirt_addr) { + return -EINVAL; +} + #endif /* CONFIG_INFINIBAND_USER_MEM */ #endif /* IB_UMEM_H */

[rdma-next,v1,2/6] RDMA/umem: Add API to find best driver supported page size in an MR

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