RDS/IB: Always use PAGE_SIZE for FMR page size

While FMRs allow significant flexibility in what size of pages they can use,
we really just want FMR pages to match CPU page size. Roland says we can
count on this always being supported, so this simplifies things.
Signed-off-by: Andy Grover <andy.grover@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/rds/ib.c

@@ -85,9 +85,6 @@ void rds_ib_add_one(struct ib_device *device)
 	rds_ibdev->max_wrs = dev_attr->max_qp_wr;
 	rds_ibdev->max_sge = min(dev_attr->max_sge, RDS_IB_MAX_SGE);
 
-	rds_ibdev->fmr_page_shift = max(9, ffs(dev_attr->page_size_cap) - 1);
-	rds_ibdev->fmr_page_size  = 1 << rds_ibdev->fmr_page_shift;
-	rds_ibdev->fmr_page_mask  = ~((u64) rds_ibdev->fmr_page_size - 1);
 	rds_ibdev->fmr_max_remaps = dev_attr->max_map_per_fmr?: 32;
 	rds_ibdev->max_fmrs = dev_attr->max_fmr ?
 			min_t(unsigned int, dev_attr->max_fmr, fmr_pool_size) :

net/rds/ib.h

@@ -159,9 +159,6 @@ struct rds_ib_device {
 	struct ib_pd		*pd;
 	struct ib_mr		*mr;
 	struct rds_ib_mr_pool	*mr_pool;
-	int			fmr_page_shift;
-	int			fmr_page_size;
-	u64			fmr_page_mask;
 	unsigned int		fmr_max_remaps;
 	unsigned int		max_fmrs;
 	int			max_sge;

net/rds/ib_rdma.c

@@ -211,7 +211,7 @@ struct rds_ib_mr_pool *rds_ib_create_mr_pool(struct rds_ib_device *rds_ibdev)
 
 	pool->fmr_attr.max_pages = fmr_message_size;
 	pool->fmr_attr.max_maps = rds_ibdev->fmr_max_remaps;
-	pool->fmr_attr.page_shift = rds_ibdev->fmr_page_shift;
+	pool->fmr_attr.page_shift = PAGE_SHIFT;
 	pool->max_free_pinned = rds_ibdev->max_fmrs * fmr_message_size / 4;
 
 	/* We never allow more than max_items MRs to be allocated.
@@ -349,13 +349,13 @@ static int rds_ib_map_fmr(struct rds_ib_device *rds_ibdev, struct rds_ib_mr *ibm
 		unsigned int dma_len = ib_sg_dma_len(dev, &scat[i]);
 		u64 dma_addr = ib_sg_dma_address(dev, &scat[i]);
 
-		if (dma_addr & ~rds_ibdev->fmr_page_mask) {
+		if (dma_addr & ~PAGE_MASK) {
 			if (i > 0)
 				return -EINVAL;
 			else
 				++page_cnt;
 		}
-		if ((dma_addr + dma_len) & ~rds_ibdev->fmr_page_mask) {
+		if ((dma_addr + dma_len) & ~PAGE_MASK) {
 			if (i < sg_dma_len - 1)
 				return -EINVAL;
 			else
@@ -365,7 +365,7 @@ static int rds_ib_map_fmr(struct rds_ib_device *rds_ibdev, struct rds_ib_mr *ibm
 		len += dma_len;
 	}
 
-	page_cnt += len >> rds_ibdev->fmr_page_shift;
+	page_cnt += len >> PAGE_SHIFT;
 	if (page_cnt > fmr_message_size)
 		return -EINVAL;
 
@@ -378,9 +378,9 @@ static int rds_ib_map_fmr(struct rds_ib_device *rds_ibdev, struct rds_ib_mr *ibm
 		unsigned int dma_len = ib_sg_dma_len(dev, &scat[i]);
 		u64 dma_addr = ib_sg_dma_address(dev, &scat[i]);
 
-		for (j = 0; j < dma_len; j += rds_ibdev->fmr_page_size)
+		for (j = 0; j < dma_len; j += PAGE_SIZE)
 			dma_pages[page_cnt++] =
-				(dma_addr & rds_ibdev->fmr_page_mask) + j;
+				(dma_addr & PAGE_MASK) + j;
 	}
 
 	ret = ib_map_phys_fmr(ibmr->fmr,