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Commit 4a353399 authored by Shiraz Saleem's avatar Shiraz Saleem Committed by Jason Gunthorpe
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RDMA/umem: Add API to find best driver supported page size in an MR 



This helper iterates through the SG list to find the best page size to use
from a bitmap of HW supported page sizes. Drivers that support multiple
page sizes, but not mixed sizes in an MR can use this API.

Suggested-by: default avatarJason Gunthorpe <jgg@ziepe.ca>
Signed-off-by: default avatarShiraz Saleem <shiraz.saleem@intel.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@mellanox.com>
parent 4c4b1996

drivers/infiniband/core/umem.c

+51 −0
Original line number Diff line number Diff line
@@ -130,6 +130,57 @@ static struct scatterlist *ib_umem_add_sg_table(struct scatterlist *sg, 
	return 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.

 *

include/rdma/ib_umem.h

+9 −0
Original line number Diff line number Diff line
@@ -87,6 +87,9 @@ void ib_umem_release(struct ib_umem *umem); 
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_best_pgsz(struct ib_umem *umem,

				     unsigned long pgsz_bitmap,

				     unsigned long virt);



#else /* CONFIG_INFINIBAND_USER_MEM */
@@ -104,6 +107,12 @@ 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_best_pgsz(struct ib_umem *umem,

					 unsigned long pgsz_bitmap,

					 unsigned long virt) {

	return -EINVAL;

}



#endif /* CONFIG_INFINIBAND_USER_MEM */



#endif /* IB_UMEM_H */

include/rdma/ib_verbs.h

+24 −0
Original line number Diff line number Diff line
@@ -3250,6 +3250,30 @@ static inline bool rdma_cap_read_inv(struct ib_device *dev, u32 port_num) 
	return rdma_protocol_iwarp(dev, port_num);

}



/**

 * rdma_find_pg_bit - Find page bit given address and HW supported page sizes

 *

 * @addr: address

 * @pgsz_bitmap: bitmap of HW supported page sizes

 */

static inline unsigned int rdma_find_pg_bit(unsigned long addr,

					    unsigned long pgsz_bitmap)

{

	unsigned long align;

	unsigned long pgsz;



	align = addr & -addr;



	/* Find page bit such that addr is aligned to the highest supported

	 * HW page size

	 */

	pgsz = pgsz_bitmap & ~(-align << 1);

	if (!pgsz)

		return __ffs(pgsz_bitmap);



	return __fls(pgsz);

}



int ib_set_vf_link_state(struct ib_device *device, int vf, u8 port,

			 int state);

int ib_get_vf_config(struct ib_device *device, int vf, u8 port,