release/5.2.47/IB-mlx5-Use-the-original-address-for-the-page-during.patch

From 697848045218a25e85ed2e7dc4d984dcff9c69b4 Mon Sep 17 00:00:00 2001
From: Danit Goldberg <danitg@mellanox.com>
Date: Mon, 16 Sep 2019 09:48:17 +0300
Subject: [PATCH] IB/mlx5: Use the original address for the page during
 free_pages

commit 130c2c576e75efaea9cd321ec4b171cc93cd0030 upstream.

The removal of 'buffer' in the patch below caused free_page() to use a
value that had been offset since the wqe pointer is adjusted while the
routine runs.

The current implementation of free_pages() rounds down to a pfn,
discarding the adjustment, but this is not the right way to use the
API. Preserve the initial value and use it for free_page().

Fixes: 0f51427bd097 ("RDMA/mlx5: Cleanup WQE page fault handler")
Link: https://lore.kernel.org/r/20190916064818.19823-2-leon@kernel.org
Signed-off-by: Danit Goldberg <danitg@mellanox.com>
Reviewed-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/drivers/infiniband/hw/mlx5/odp.c b/drivers/infiniband/hw/mlx5/odp.c
index fda3dfd6f87b..e0ecb540c67e 100644
--- a/drivers/infiniband/hw/mlx5/odp.c
+++ b/drivers/infiniband/hw/mlx5/odp.c
@@ -1205,7 +1205,7 @@ static void mlx5_ib_mr_wqe_pfault_handler(struct mlx5_ib_dev *dev,
 {
 	bool sq = pfault->type & MLX5_PFAULT_REQUESTOR;
 	u16 wqe_index = pfault->wqe.wqe_index;
-	void *wqe = NULL, *wqe_end = NULL;
+	void *wqe, *wqe_start = NULL, *wqe_end = NULL;
 	u32 bytes_mapped, total_wqe_bytes;
 	struct mlx5_core_rsc_common *res;
 	int resume_with_error = 1;
@@ -1226,12 +1226,13 @@ static void mlx5_ib_mr_wqe_pfault_handler(struct mlx5_ib_dev *dev,
 		goto resolve_page_fault;
 	}
 
-	wqe = (void *)__get_free_page(GFP_KERNEL);
-	if (!wqe) {
+	wqe_start = (void *)__get_free_page(GFP_KERNEL);
+	if (!wqe_start) {
 		mlx5_ib_err(dev, "Error allocating memory for IO page fault handling.\n");
 		goto resolve_page_fault;
 	}
 
+	wqe = wqe_start;
 	qp = (res->res == MLX5_RES_QP) ? res_to_qp(res) : NULL;
 	if (qp && sq) {
 		ret = mlx5_ib_read_user_wqe_sq(qp, wqe_index, wqe, PAGE_SIZE,
@@ -1286,7 +1287,7 @@ static void mlx5_ib_mr_wqe_pfault_handler(struct mlx5_ib_dev *dev,
 		    pfault->wqe.wq_num, resume_with_error,
 		    pfault->type);
 	mlx5_core_res_put(res);
-	free_page((unsigned long)wqe);
+	free_page((unsigned long)wqe_start);
 }
 
 static int pages_in_range(u64 address, u32 length)
-- 
2.27.0