Re: [PATCH] net: qca_spi: Fix race condition in spi transfers

[kbuild test robot <lkp@intel.com>]

Hi Stefan,

I love your patch! Perhaps something to improve:

[auto build test WARNING on net-next/master]
[also build test WARNING on v4.19-rc2 next-20180831]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Stefan-Wahren/net-qca_spi-Fix-race-condition-in-spi-transfers/20180903-112513
reproduce:
        # apt-get install sparse
        make ARCH=x86_64 allmodconfig
        make C=1 CF=-D__CHECK_ENDIAN__
:::::: branch date: 4 hours ago
:::::: commit date: 4 hours ago

>> drivers/net/ethernet/qualcomm/qca_7k.c:78:27: sparse: cast to restricted __be16
>> drivers/net/ethernet/qualcomm/qca_7k.c:78:27: sparse: cast to restricted __be16
>> drivers/net/ethernet/qualcomm/qca_7k.c:78:27: sparse: cast to restricted __be16
>> drivers/net/ethernet/qualcomm/qca_7k.c:78:27: sparse: cast to restricted __be16

# https://github.com/0day-ci/linux/commit/5fb0b49d203c5085fd770521b6c18d0becda9086
git remote add linux-review https://github.com/0day-ci/linux
git remote update linux-review
git checkout 5fb0b49d203c5085fd770521b6c18d0becda9086
vim +78 drivers/net/ethernet/qualcomm/qca_7k.c

291ab06e Stefan Wahren 2014-09-26  42  
291ab06e Stefan Wahren 2014-09-26  43  int
291ab06e Stefan Wahren 2014-09-26  44  qcaspi_read_register(struct qcaspi *qca, u16 reg, u16 *result)
291ab06e Stefan Wahren 2014-09-26  45  {
291ab06e Stefan Wahren 2014-09-26  46  	__be16 tx_data;
5fb0b49d Stefan Wahren 2018-08-31  47  	struct spi_transfer transfer[2];
5fb0b49d Stefan Wahren 2018-08-31  48  	struct spi_message msg;
291ab06e Stefan Wahren 2014-09-26  49  	int ret;
291ab06e Stefan Wahren 2014-09-26  50  
5fb0b49d Stefan Wahren 2018-08-31  51  	memset(transfer, 0, sizeof(transfer));
5fb0b49d Stefan Wahren 2018-08-31  52  
5fb0b49d Stefan Wahren 2018-08-31  53  	spi_message_init(&msg);
5fb0b49d Stefan Wahren 2018-08-31  54  
291ab06e Stefan Wahren 2014-09-26  55  	tx_data = cpu_to_be16(QCA7K_SPI_READ | QCA7K_SPI_INTERNAL | reg);
5fb0b49d Stefan Wahren 2018-08-31  56  	*result = 0;
5fb0b49d Stefan Wahren 2018-08-31  57  
5fb0b49d Stefan Wahren 2018-08-31  58  	transfer[0].tx_buf = &tx_data;
5fb0b49d Stefan Wahren 2018-08-31  59  	transfer[0].len = QCASPI_CMD_LEN;
5fb0b49d Stefan Wahren 2018-08-31  60  	transfer[1].rx_buf = result;
5fb0b49d Stefan Wahren 2018-08-31  61  	transfer[1].len = QCASPI_CMD_LEN;
5fb0b49d Stefan Wahren 2018-08-31  62  
5fb0b49d Stefan Wahren 2018-08-31  63  	spi_message_add_tail(&transfer[0], &msg);
291ab06e Stefan Wahren 2014-09-26  64  
291ab06e Stefan Wahren 2014-09-26  65  	if (qca->legacy_mode) {
5fb0b49d Stefan Wahren 2018-08-31  66  		spi_sync(qca->spi_dev, &msg);
5fb0b49d Stefan Wahren 2018-08-31  67  		spi_message_init(&msg);
291ab06e Stefan Wahren 2014-09-26  68  	}
5fb0b49d Stefan Wahren 2018-08-31  69  	spi_message_add_tail(&transfer[1], &msg);
5fb0b49d Stefan Wahren 2018-08-31  70  	ret = spi_sync(qca->spi_dev, &msg);
291ab06e Stefan Wahren 2014-09-26  71  
291ab06e Stefan Wahren 2014-09-26  72  	if (!ret)
5fb0b49d Stefan Wahren 2018-08-31  73  		ret = msg.status;
291ab06e Stefan Wahren 2014-09-26  74  
5fb0b49d Stefan Wahren 2018-08-31  75  	if (ret) {
291ab06e Stefan Wahren 2014-09-26  76  		qcaspi_spi_error(qca);
5fb0b49d Stefan Wahren 2018-08-31  77  	} else {
5fb0b49d Stefan Wahren 2018-08-31 @78  		*result = be16_to_cpu(*result);
5fb0b49d Stefan Wahren 2018-08-31  79  	}
291ab06e Stefan Wahren 2014-09-26  80  
291ab06e Stefan Wahren 2014-09-26  81  	return ret;
291ab06e Stefan Wahren 2014-09-26  82  }
291ab06e Stefan Wahren 2014-09-26  83  

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