From 4772e03d239484f3461e33c79d721c8ea03f7416 Mon Sep 17 00:00:00 2001
From: Lijun Ou <oulijun@huawei.com>
Date: Sun, 7 Apr 2019 13:23:38 +0800
Subject: [PATCH] RDMA/hns: Fix bug that caused srq creation to fail

Due to the incorrect use of the seg and obj information, the position of
the mtt is calculated incorrectly, and the free space of the page is not
enough to store the entire mtt, resulting in access to the next page. This
patch fixes this problem.

 Unable to handle kernel paging request at virtual address ffff00006e3cd000
 ...
 Call trace:
  hns_roce_write_mtt+0x154/0x2f0 [hns_roce]
  hns_roce_buf_write_mtt+0xa8/0xd8 [hns_roce]
  hns_roce_create_srq+0x74c/0x808 [hns_roce]
  ib_create_srq+0x28/0xc8

Fixes: 0203b14c4f32 ("RDMA/hns: Unify the calculation for hem index in hip08")
Signed-off-by: chenglang <chenglang@huawei.com>
Signed-off-by: Lijun Ou <oulijun@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
---
 drivers/infiniband/hw/hns/hns_roce_hem.c | 6 ++++--
 drivers/infiniband/hw/hns/hns_roce_mr.c  | 4 ++--
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/infiniband/hw/hns/hns_roce_hem.c b/drivers/infiniband/hw/hns/hns_roce_hem.c
index f1fec56f3ff49..8e29dbb5b5fbc 100644
--- a/drivers/infiniband/hw/hns/hns_roce_hem.c
+++ b/drivers/infiniband/hw/hns/hns_roce_hem.c
@@ -792,6 +792,8 @@ void *hns_roce_table_find(struct hns_roce_dev *hr_dev,
 		idx_offset = (obj & (table->num_obj - 1)) % obj_per_chunk;
 		dma_offset = offset = idx_offset * table->obj_size;
 	} else {
+		u32 seg_size = 64; /* 8 bytes per BA and 8 BA per segment */
+
 		hns_roce_calc_hem_mhop(hr_dev, table, &mhop_obj, &mhop);
 		/* mtt mhop */
 		i = mhop.l0_idx;
@@ -803,8 +805,8 @@ void *hns_roce_table_find(struct hns_roce_dev *hr_dev,
 			hem_idx = i;
 
 		hem = table->hem[hem_idx];
-		dma_offset = offset = (obj & (table->num_obj - 1)) *
-				       table->obj_size % mhop.bt_chunk_size;
+		dma_offset = offset = (obj & (table->num_obj - 1)) * seg_size %
+				       mhop.bt_chunk_size;
 		if (mhop.hop_num == 2)
 			dma_offset = offset = 0;
 	}
diff --git a/drivers/infiniband/hw/hns/hns_roce_mr.c b/drivers/infiniband/hw/hns/hns_roce_mr.c
index b09f1cde2ff54..08be0e4eabcd7 100644
--- a/drivers/infiniband/hw/hns/hns_roce_mr.c
+++ b/drivers/infiniband/hw/hns/hns_roce_mr.c
@@ -746,7 +746,6 @@ static int hns_roce_write_mtt_chunk(struct hns_roce_dev *hr_dev,
 	struct hns_roce_hem_table *table;
 	dma_addr_t dma_handle;
 	__le64 *mtts;
-	u32 s = start_index * sizeof(u64);
 	u32 bt_page_size;
 	u32 i;
 
@@ -780,7 +779,8 @@ static int hns_roce_write_mtt_chunk(struct hns_roce_dev *hr_dev,
 		return -EINVAL;
 
 	mtts = hns_roce_table_find(hr_dev, table,
-				mtt->first_seg + s / hr_dev->caps.mtt_entry_sz,
+				mtt->first_seg +
+				start_index / HNS_ROCE_MTT_ENTRY_PER_SEG,
 				&dma_handle);
 	if (!mtts)
 		return -ENOMEM;
-- 
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