linux-kernel - [PATCH 5.16 0826/1039] dma-buf: cma

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Date:   Mon, 24 Jan 2022 19:43:35 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Weizhao Ouyang <o451686892@...il.com>,
        John Stultz <john.stultz@...aro.org>,
        Sumit Semwal <sumit.semwal@...aro.org>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.16 0826/1039] dma-buf: cma_heap: Fix mutex locking section

From: Weizhao Ouyang <o451686892@...il.com>

[ Upstream commit 54329e6f7beea6af56c1230da293acc97d6a6ee7 ]

Fix cma_heap_buffer mutex locking critical section to protect vmap_cnt
and vaddr.

Fixes: a5d2d29e24be ("dma-buf: heaps: Move heap-helper logic into the cma_heap implementation")
Signed-off-by: Weizhao Ouyang <o451686892@...il.com>
Acked-by: John Stultz <john.stultz@...aro.org>
Signed-off-by: Sumit Semwal <sumit.semwal@...aro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220104073545.124244-1-o451686892@gmail.com
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/dma-buf/heaps/cma_heap.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/dma-buf/heaps/cma_heap.c b/drivers/dma-buf/heaps/cma_heap.c
index 0c05b79870f96..83f02bd51dda6 100644
--- a/drivers/dma-buf/heaps/cma_heap.c
+++ b/drivers/dma-buf/heaps/cma_heap.c
@@ -124,10 +124,11 @@ static int cma_heap_dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
 	struct cma_heap_buffer *buffer = dmabuf->priv;
 	struct dma_heap_attachment *a;
 
+	mutex_lock(&buffer->lock);
+
 	if (buffer->vmap_cnt)
 		invalidate_kernel_vmap_range(buffer->vaddr, buffer->len);
 
-	mutex_lock(&buffer->lock);
 	list_for_each_entry(a, &buffer->attachments, list) {
 		if (!a->mapped)
 			continue;
@@ -144,10 +145,11 @@ static int cma_heap_dma_buf_end_cpu_access(struct dma_buf *dmabuf,
 	struct cma_heap_buffer *buffer = dmabuf->priv;
 	struct dma_heap_attachment *a;
 
+	mutex_lock(&buffer->lock);
+
 	if (buffer->vmap_cnt)
 		flush_kernel_vmap_range(buffer->vaddr, buffer->len);
 
-	mutex_lock(&buffer->lock);
 	list_for_each_entry(a, &buffer->attachments, list) {
 		if (!a->mapped)
 			continue;
-- 
2.34.1