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From:   Shunyong Yang <shunyong.yang@hxt-semitech.com>
To:     <okaya@kernel.org>
CC:     <andy.gross@linaro.org>, <david.brown@linaro.org>,
        <vkoul@kernel.org>, <dan.j.williams@intel.com>,
        <dmaengine@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        Shunyong Yang <shunyong.yang@hxt-semitech.com>,
        Joey Zheng <yu.zheng@hxt-semitech.com>
Subject: [PATCH 1/2] dmaengine: qcom_hidma: initialize tx flags in hidma_prep_dma_*
Date:   Fri, 7 Dec 2018 12:28:56 +0800
Message-ID: <81c9fe2de4b5dac1d5b974f5305e35bf1cf5d127.1544156508.git.shunyong.yang@hxt-semitech.com>
MIME-Version: 1.0
Content-Type: text/plain
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

In async_tx_test_ack(), it uses flags in struct dma_async_tx_descriptor
to check the ACK status. As hidma reuses the descriptor in a free list
when hidma_prep_dma_*(memcpy/memset) is called, the flag will keep ACKed
if the descriptor has been used before. This will cause a BUG_ON in
async_tx_quiesce().

  kernel BUG at crypto/async_tx/async_tx.c:282!
  Internal error: Oops - BUG: 0 1 SMP
  ...
  task: ffff8017dd3ec000 task.stack: ffff8017dd3e8000
  PC is at async_tx_quiesce+0x54/0x78 [async_tx]
  LR is at async_trigger_callback+0x98/0x110 [async_tx]

This patch initializes flags in dma_async_tx_descriptor by the flags
passed from the caller when hidma_prep_dma_*(memcpy/memset) is called.

Cc: Joey Zheng <yu.zheng@hxt-semitech.com>
Signed-off-by: Shunyong Yang <shunyong.yang@hxt-semitech.com>
---
 drivers/dma/qcom/hidma.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/dma/qcom/hidma.c b/drivers/dma/qcom/hidma.c
index 43d4b00b8138..9d639ed1955a 100644
--- a/drivers/dma/qcom/hidma.c
+++ b/drivers/dma/qcom/hidma.c
@@ -415,6 +415,7 @@ static int hidma_alloc_chan_resources(struct dma_chan *dmach)
 	if (!mdesc)
 		return NULL;
 
+	mdesc->desc.flags = flags;
 	hidma_ll_set_transfer_params(mdma->lldev, mdesc->tre_ch,
 				     src, dest, len, flags,
 				     HIDMA_TRE_MEMCPY);
@@ -447,6 +448,7 @@ static int hidma_alloc_chan_resources(struct dma_chan *dmach)
 	if (!mdesc)
 		return NULL;
 
+	mdesc->desc.flags = flags;
 	hidma_ll_set_transfer_params(mdma->lldev, mdesc->tre_ch,
 				     value, dest, len, flags,
 				     HIDMA_TRE_MEMSET);
-- 
1.8.3.1