From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Guangming <Guangming.Cao@mediatek.com>,
        Robin Murphy <robin.murphy@arm.com>,
        =?UTF-8?q?Christian=20K=C3=B6nig?= <christian.koenig@amd.com>,
        John Stultz <john.stultz@linaro.org>,
        Sumit Semwal <sumit.semwal@linaro.org>
Subject: [PATCH 5.15 060/207] dma-buf: system_heap: Use for_each_sgtable_sg in pages free flow
Date:   Mon,  6 Dec 2021 15:55:14 +0100
Message-Id: <20211206145612.317212725@linuxfoundation.org>
In-Reply-To: <20211206145610.172203682@linuxfoundation.org>
References: <20211206145610.172203682@linuxfoundation.org>
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From: Guangming <Guangming.Cao@mediatek.com>

commit 679d94cd7d900871e5bc9cf780bd5b73af35ab42 upstream.

For previous version, it uses 'sg_table.nent's to traverse sg_table in pages
free flow.
However, 'sg_table.nents' is reassigned in 'dma_map_sg', it means the number of
created entries in the DMA adderess space.
So, use 'sg_table.nents' in pages free flow will case some pages can't be freed.

Here we should use sg_table.orig_nents to free pages memory, but use the
sgtable helper 'for each_sgtable_sg'(, instead of the previous rather common
helper 'for_each_sg' which maybe cause memory leak) is much better.

Fixes: d963ab0f15fb0 ("dma-buf: system_heap: Allocate higher order pages if available")
Signed-off-by: Guangming <Guangming.Cao@mediatek.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Cc: <stable@vger.kernel.org> # 5.11.*
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20211126074904.88388-1-guangming.cao@mediatek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/dma-buf/heaps/system_heap.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/dma-buf/heaps/system_heap.c
+++ b/drivers/dma-buf/heaps/system_heap.c
@@ -289,7 +289,7 @@ static void system_heap_dma_buf_release(
 	int i;
 
 	table = &buffer->sg_table;
-	for_each_sg(table->sgl, sg, table->nents, i) {
+	for_each_sgtable_sg(table, sg, i) {
 		struct page *page = sg_page(sg);
 
 		__free_pages(page, compound_order(page));