[PATCH rdma-next 5/6] RDMA/mlx5: mlx5_umem_find_best_quantized_pgoff() for CQ

[Leon Romanovsky <leon@kernel.org>]

From: Jason Gunthorpe <jgg@nvidia.com>

This fixes a bug where the page_offset was not being considered when
building a CQ. The PRM says it 'must be zero', so use a variant of
mlx5_umem_find_best_quantized_pgoff() with a 0 pgoff_bitmask to force this
result.

YISHAI: Why does the PRM say 'must be zero' and then give math to compute
it in red highlight?

Fixes: e126ba97dba9 ("mlx5: Add driver for Mellanox Connect-IB adapters")
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
---
 drivers/infiniband/hw/mlx5/cq.c      | 48 +++++++++++++++++-------
 drivers/infiniband/hw/mlx5/mem.c     | 55 ----------------------------
 drivers/infiniband/hw/mlx5/mlx5_ib.h | 14 +++++--
 3 files changed, 45 insertions(+), 72 deletions(-)

diff --git a/drivers/infiniband/hw/mlx5/cq.c b/drivers/infiniband/hw/mlx5/cq.c
index 9ab93d730769..eb92cefffd77 100644
--- a/drivers/infiniband/hw/mlx5/cq.c
+++ b/drivers/infiniband/hw/mlx5/cq.c
@@ -707,8 +707,9 @@ static int create_cq_user(struct mlx5_ib_dev *dev, struct ib_udata *udata,
 			  int *cqe_size, int *index, int *inlen)
 {
 	struct mlx5_ib_create_cq ucmd = {};
+	unsigned long page_size;
+	unsigned int page_offset_quantized;
 	size_t ucmdlen;
-	int page_shift;
 	__be64 *pas;
 	int ncont;
 	void *cqc;
@@ -741,17 +742,24 @@ static int create_cq_user(struct mlx5_ib_dev *dev, struct ib_udata *udata,
 		return err;
 	}
 
+	page_size = mlx5_umem_find_best_cq_quantized_pgoff(
+		cq->buf.umem, cqc, log_page_size, MLX5_ADAPTER_PAGE_SHIFT,
+		page_offset, 64, &page_offset_quantized);
+	if (!page_size) {
+		err = -EINVAL;
+		goto err_umem;
+	}
+
 	err = mlx5_ib_db_map_user(context, udata, ucmd.db_addr, &cq->db);
 	if (err)
 		goto err_umem;
 
-	mlx5_ib_cont_pages(cq->buf.umem, ucmd.buf_addr, 0, &page_shift);
-	ncont = ib_umem_num_dma_blocks(cq->buf.umem, 1UL << page_shift);
+	ncont = ib_umem_num_dma_blocks(cq->buf.umem, page_size);
 	mlx5_ib_dbg(
 		dev,
-		"addr 0x%llx, size %u, npages %zu, page_shift %d, ncont %d\n",
+		"addr 0x%llx, size %u, npages %zu, page_size %lu, ncont %d\n",
 		ucmd.buf_addr, entries * ucmd.cqe_size,
-		ib_umem_num_pages(cq->buf.umem), page_shift, ncont);
+		ib_umem_num_pages(cq->buf.umem), page_size, ncont);
 
 	*inlen = MLX5_ST_SZ_BYTES(create_cq_in) +
 		 MLX5_FLD_SZ_BYTES(create_cq_in, pas[0]) * ncont;
@@ -762,11 +770,12 @@ static int create_cq_user(struct mlx5_ib_dev *dev, struct ib_udata *udata,
 	}
 
 	pas = (__be64 *)MLX5_ADDR_OF(create_cq_in, *cqb, pas);
-	mlx5_ib_populate_pas(cq->buf.umem, 1UL << page_shift, pas, 0);
+	mlx5_ib_populate_pas(cq->buf.umem, page_size, pas, 0);
 
 	cqc = MLX5_ADDR_OF(create_cq_in, *cqb, cq_context);
 	MLX5_SET(cqc, cqc, log_page_size,
-		 page_shift - MLX5_ADAPTER_PAGE_SHIFT);
+		 order_base_2(page_size) - MLX5_ADAPTER_PAGE_SHIFT);
+	MLX5_SET(cqc, cqc, page_offset, page_offset_quantized);
 
 	if (ucmd.flags & MLX5_IB_CREATE_CQ_FLAGS_UAR_PAGE_INDEX) {
 		*index = ucmd.uar_page_index;
@@ -1131,7 +1140,7 @@ int mlx5_ib_modify_cq(struct ib_cq *cq, u16 cq_count, u16 cq_period)
 
 static int resize_user(struct mlx5_ib_dev *dev, struct mlx5_ib_cq *cq,
 		       int entries, struct ib_udata *udata,
-		       int *page_shift, int *cqe_size)
+		       int *cqe_size)
 {
 	struct mlx5_ib_resize_cq ucmd;
 	struct ib_umem *umem;
@@ -1156,8 +1165,6 @@ static int resize_user(struct mlx5_ib_dev *dev, struct mlx5_ib_cq *cq,
 		return err;
 	}
 
-	mlx5_ib_cont_pages(umem, ucmd.buf_addr, 0, page_shift);
-
 	cq->resize_umem = umem;
 	*cqe_size = ucmd.cqe_size;
 
@@ -1250,7 +1257,8 @@ int mlx5_ib_resize_cq(struct ib_cq *ibcq, int entries, struct ib_udata *udata)
 	int err;
 	int npas;
 	__be64 *pas;
-	int page_shift;
+	unsigned int page_offset_quantized = 0;
+	unsigned int page_shift;
 	int inlen;
 	int cqe_size;
 	unsigned long flags;
@@ -1277,11 +1285,22 @@ int mlx5_ib_resize_cq(struct ib_cq *ibcq, int entries, struct ib_udata *udata)
 
 	mutex_lock(&cq->resize_mutex);
 	if (udata) {
-		err = resize_user(dev, cq, entries, udata, &page_shift,
-				  &cqe_size);
+		unsigned long page_size;
+
+		err = resize_user(dev, cq, entries, udata, &cqe_size);
 		if (err)
 			goto ex;
-		npas = ib_umem_num_dma_blocks(cq->resize_umem, 1UL << page_shift);
+
+		page_size = mlx5_umem_find_best_cq_quantized_pgoff(
+			cq->resize_umem, cqc, log_page_size,
+			MLX5_ADAPTER_PAGE_SHIFT, page_offset, 64,
+			&page_offset_quantized);
+		if (!page_size) {
+			err = -EINVAL;
+			goto ex_resize;
+		}
+		npas = ib_umem_num_dma_blocks(cq->resize_umem, page_size);
+		page_shift = order_base_2(page_size);
 	} else {
 		struct mlx5_frag_buf *frag_buf;
 
@@ -1320,6 +1339,7 @@ int mlx5_ib_resize_cq(struct ib_cq *ibcq, int entries, struct ib_udata *udata)
 
 	MLX5_SET(cqc, cqc, log_page_size,
 		 page_shift - MLX5_ADAPTER_PAGE_SHIFT);
+	MLX5_SET(cqc, cqc, page_offset, page_offset_quantized);
 	MLX5_SET(cqc, cqc, cqe_sz,
 		 cqe_sz_to_mlx_sz(cqe_size,
 				  cq->private_flags &
diff --git a/drivers/infiniband/hw/mlx5/mem.c b/drivers/infiniband/hw/mlx5/mem.c
index e38f9f2bf181..9031c2c153e1 100644
--- a/drivers/infiniband/hw/mlx5/mem.c
+++ b/drivers/infiniband/hw/mlx5/mem.c
@@ -36,61 +36,6 @@
 #include "mlx5_ib.h"
 #include <linux/jiffies.h>
 
-/* @umem: umem object to scan
- * @addr: ib virtual address requested by the user
- * @max_page_shift: high limit for page_shift - 0 means no limit
- * @shift: page shift for the compound pages found in the region
- */
-void mlx5_ib_cont_pages(struct ib_umem *umem, u64 addr,
-			unsigned long max_page_shift, int *shift)
-{
-	unsigned long tmp;
-	unsigned long m;
-	u64 base = ~0, p = 0;
-	u64 len, pfn;
-	int i = 0;
-	struct scatterlist *sg;
-	int entry;
-
-	if (umem->is_odp) {
-		struct ib_umem_odp *odp = to_ib_umem_odp(umem);
-
-		*shift = odp->page_shift;
-		return;
-	}
-
-	addr = addr >> PAGE_SHIFT;
-	tmp = (unsigned long)addr;
-	m = find_first_bit(&tmp, BITS_PER_LONG);
-	if (max_page_shift)
-		m = min_t(unsigned long, max_page_shift - PAGE_SHIFT, m);
-
-	for_each_sg(umem->sg_head.sgl, sg, umem->nmap, entry) {
-		len = sg_dma_len(sg) >> PAGE_SHIFT;
-		pfn = sg_dma_address(sg) >> PAGE_SHIFT;
-		if (base + p != pfn) {
-			/* If either the offset or the new
-			 * base are unaligned update m
-			 */
-			tmp = (unsigned long)(pfn | p);
-			if (!IS_ALIGNED(tmp, 1 << m))
-				m = find_first_bit(&tmp, BITS_PER_LONG);
-
-			base = pfn;
-			p = 0;
-		}
-
-		p += len;
-		i += len;
-	}
-
-	if (i)
-		m = min_t(unsigned long, ilog2(roundup_pow_of_two(i)), m);
-	else
-		m  = 0;
-	*shift = PAGE_SHIFT + m;
-}
-
 /*
  * Fill in a physical address list. ib_umem_num_dma_blocks() entries will be
  * filled in the pas array.
diff --git a/drivers/infiniband/hw/mlx5/mlx5_ib.h b/drivers/infiniband/hw/mlx5/mlx5_ib.h
index 9777103af575..254668d31988 100644
--- a/drivers/infiniband/hw/mlx5/mlx5_ib.h
+++ b/drivers/infiniband/hw/mlx5/mlx5_ib.h
@@ -106,6 +106,17 @@ unsigned long __mlx5_umem_find_best_quantized_pgoff(
 		GENMASK(31, order_base_2(scale)), scale,                       \
 		page_offset_quantized)
 
+/* PRM says page_offset must be 0 for CQ */
+#define mlx5_umem_find_best_cq_quantized_pgoff(umem, typ, log_pgsz_fld,        \
+					       pgsz_shift, page_offset_fld,    \
+					       scale, page_offset_quantized)   \
+	__mlx5_umem_find_best_quantized_pgoff(                                 \
+		umem,                                                          \
+		__mlx5_log_page_size_to_bitmap(                                \
+			__mlx5_bit_sz(typ, log_pgsz_fld), pgsz_shift),         \
+		__mlx5_bit_sz(typ, page_offset_fld), 0, scale,                 \
+		page_offset_quantized)
+
 enum {
 	MLX5_IB_MMAP_OFFSET_START = 9,
 	MLX5_IB_MMAP_OFFSET_END = 255,
@@ -1292,9 +1303,6 @@ int mlx5_query_mad_ifc_port(struct ib_device *ibdev, u8 port,
 			    struct ib_port_attr *props);
 int mlx5_ib_query_port(struct ib_device *ibdev, u8 port,
 		       struct ib_port_attr *props);
-void mlx5_ib_cont_pages(struct ib_umem *umem, u64 addr,
-			unsigned long max_page_shift,
-			int *shift);
 void mlx5_ib_populate_pas(struct ib_umem *umem, size_t page_size, __be64 *pas,
 			  u64 access_flags);
 void mlx5_ib_copy_pas(u64 *old, u64 *new, int step, int num);
-- 
2.26.2