From: Eran Ben Elisha <eranbe@mellanox.com>
Date: Sun, 3 May 2020 11:01:39 +0300
Subject: net/mlx5: Fix a bug of releasing wrong chunks on > 4K page size
 systems
Patch-mainline: v5.8-rc1
Git-commit: e7f860e2106a4c288d98308c59545ddd350e4739
References: jsc#SLE-15172

On systems with page size larger than 4K, a fwp object has few 4K chunks.
Fix a bug in fwp free flow where the chunk address was dropped and
fwp->addr was used instead (first chunk address). This caused a wrong
update of fwp->bitmask which later can cause errors in re-alloc fwp
chunk flow.

In order to fix this it, re-factor the release flow:
- Free 4k: Releases a specific 4k chunk inside the fwp, defined by
  starting address.
- Free fwp: Unconditionally release the whole fwp and its resources.
Free addr will call free fwp if all chunks were released, in order to do
code sharing.

In addition, fix npages to count for all released chunks correctly.

Fixes: c6168161f693 ("net/mlx5: Add support for release all pages event")
Signed-off-by: Eran Ben Elisha <eranbe@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/mellanox/mlx5/core/pagealloc.c |   44 ++++++++++----------
 1 file changed, 22 insertions(+), 22 deletions(-)

--- a/drivers/net/ethernet/mellanox/mlx5/core/pagealloc.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/pagealloc.c
@@ -188,35 +188,35 @@ static int alloc_4k(struct mlx5_core_dev
 
 #define MLX5_U64_4K_PAGE_MASK ((~(u64)0U) << PAGE_SHIFT)
 
-static void free_fwp(struct mlx5_core_dev *dev, struct fw_page *fwp)
+static void free_fwp(struct mlx5_core_dev *dev, struct fw_page *fwp,
+		     bool in_free_list)
 {
-	int n = (fwp->addr & ~MLX5_U64_4K_PAGE_MASK) >> MLX5_ADAPTER_PAGE_SHIFT;
-
-	fwp->free_count++;
-	set_bit(n, &fwp->bitmask);
-	if (fwp->free_count == MLX5_NUM_4K_IN_PAGE) {
-		rb_erase(&fwp->rb_node, &dev->priv.page_root);
-		if (fwp->free_count != 1)
-			list_del(&fwp->list);
-		dma_unmap_page(dev->device, fwp->addr & MLX5_U64_4K_PAGE_MASK,
-			       PAGE_SIZE, DMA_BIDIRECTIONAL);
-		__free_page(fwp->page);
-		kfree(fwp);
-	} else if (fwp->free_count == 1) {
-		list_add(&fwp->list, &dev->priv.free_list);
-	}
+	rb_erase(&fwp->rb_node, &dev->priv.page_root);
+	if (in_free_list)
+		list_del(&fwp->list);
+	dma_unmap_page(dev->device, fwp->addr & MLX5_U64_4K_PAGE_MASK,
+		       PAGE_SIZE, DMA_BIDIRECTIONAL);
+	__free_page(fwp->page);
+	kfree(fwp);
 }
 
-static void free_addr(struct mlx5_core_dev *dev, u64 addr)
+static void free_4k(struct mlx5_core_dev *dev, u64 addr)
 {
 	struct fw_page *fwp;
+	int n;
 
 	fwp = find_fw_page(dev, addr & MLX5_U64_4K_PAGE_MASK);
 	if (!fwp) {
 		mlx5_core_warn_rl(dev, "page not found\n");
 		return;
 	}
-	free_fwp(dev, fwp);
+	n = (addr & ~MLX5_U64_4K_PAGE_MASK) >> MLX5_ADAPTER_PAGE_SHIFT;
+	fwp->free_count++;
+	set_bit(n, &fwp->bitmask);
+	if (fwp->free_count == MLX5_NUM_4K_IN_PAGE)
+		free_fwp(dev, fwp, fwp->free_count != 1);
+	else if (fwp->free_count == 1)
+		list_add(&fwp->list, &dev->priv.free_list);
 }
 
 static int alloc_system_page(struct mlx5_core_dev *dev, u16 func_id)
@@ -340,7 +340,7 @@ retry:
 
 out_4k:
 	for (i--; i >= 0; i--)
-		free_addr(dev, MLX5_GET64(manage_pages_in, in, pas[i]));
+		free_4k(dev, MLX5_GET64(manage_pages_in, in, pas[i]));
 out_free:
 	kvfree(in);
 	if (notify_fail)
@@ -361,8 +361,8 @@ static void release_all_pages(struct mlx
 		p = rb_next(p);
 		if (fwp->func_id != func_id)
 			continue;
-		free_fwp(dev, fwp);
-		npages++;
+		npages += (MLX5_NUM_4K_IN_PAGE - fwp->free_count);
+		free_fwp(dev, fwp, fwp->free_count);
 	}
 
 	dev->priv.fw_pages -= npages;
@@ -446,7 +446,7 @@ static int reclaim_pages(struct mlx5_cor
 	}
 
 	for (i = 0; i < num_claimed; i++)
-		free_addr(dev, MLX5_GET64(manage_pages_out, out, pas[i]));
+		free_4k(dev, MLX5_GET64(manage_pages_out, out, pas[i]));
 
 	if (nclaimed)
 		*nclaimed = num_claimed;