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Message-ID: <8096b5cc-cc25-d24d-f5af-e86220e25c09@quicinc.com>
Date:   Wed, 13 Sep 2023 16:50:27 +0800
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Subject: Re: [PATCH 1/2] bus: mhi: host: Add spinlock to protect WP access
 when queueing TREs
To:     Dan Carpenter <dan.carpenter@linaro.org>,
        <oe-kbuild@lists.linux.dev>, <mani@kernel.org>,
        <quic_jhugo@quicinc.com>
CC:     <lkp@intel.com>, <oe-kbuild-all@lists.linux.dev>,
        <mhi@lists.linux.dev>, <linux-arm-msm@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <quic_cang@quicinc.com>,
        <quic_mrana@quicinc.com>, Bhaumik Bhatt <bbhatt@codeaurora.org>
References: <6fd73c41-852d-4d4a-9a48-b0c6dffe2515@kadam.mountain>
Content-Language: en-US
From:   Qiang Yu <quic_qianyu@quicinc.com>
In-Reply-To: <6fd73c41-852d-4d4a-9a48-b0c6dffe2515@kadam.mountain>
Content-Type: text/plain; charset="UTF-8"; format=flowed
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Precedence: bulk


On 9/13/2023 3:18 PM, Dan Carpenter wrote:
> Hi Qiang,
>
> kernel test robot noticed the following build warnings:
>
> https://git-scm.com/docs/git-format-patch#_base_tree_information]
>
> url:    https://github.com/intel-lab-lkp/linux/commits/Qiang-Yu/bus-mhi-host-Add-spinlock-to-protect-WP-access-when-queueing-TREs/20230912-072349
> base:   linus/master
> patch link:    https://lore.kernel.org/r/1694426069-74140-2-git-send-email-quic_qianyu%40quicinc.com
> patch subject: [PATCH 1/2] bus: mhi: host: Add spinlock to protect WP access when queueing TREs
> config: i386-randconfig-141-20230913 (https://download.01.org/0day-ci/archive/20230913/202309131155.OQbvsWhZ-lkp@intel.com/config)
> compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
> reproduce: (https://download.01.org/0day-ci/archive/20230913/202309131155.OQbvsWhZ-lkp@intel.com/reproduce)
>
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
> | Closes: https://lore.kernel.org/r/202309131155.OQbvsWhZ-lkp@intel.com/
>
> smatch warnings:
> drivers/bus/mhi/host/main.c:1249 mhi_gen_tre() warn: inconsistent returns '&mhi_chan->lock'.
>
> vim +1249 drivers/bus/mhi/host/main.c
Thanks for reporting this error. Added write_unlock_bh(&mhi_chan->lock) 
before return because of error process in v2 patch.
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1200  int mhi_gen_tre(struct mhi_controller *mhi_cntrl, struct mhi_chan *mhi_chan,
> cd116318803f5e drivers/bus/mhi/core/main.c Hemant Kumar          2020-05-21  1201  			struct mhi_buf_info *info, enum mhi_flags flags)
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1202  {
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1203  	struct mhi_ring *buf_ring, *tre_ring;
> 84f5f31f110e5e drivers/bus/mhi/host/main.c Manivannan Sadhasivam 2022-03-01  1204  	struct mhi_ring_element *mhi_tre;
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1205  	struct mhi_buf_info *buf_info;
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1206  	int eot, eob, chain, bei;
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1207  	int ret;
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1208
> c8a037317010d5 drivers/bus/mhi/host/main.c Bhaumik Bhatt         2023-09-11  1209  	/* Protect accesses for reading and incrementing WP */
> c8a037317010d5 drivers/bus/mhi/host/main.c Bhaumik Bhatt         2023-09-11  1210  	write_lock_bh(&mhi_chan->lock);
> c8a037317010d5 drivers/bus/mhi/host/main.c Bhaumik Bhatt         2023-09-11  1211
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1212  	buf_ring = &mhi_chan->buf_ring;
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1213  	tre_ring = &mhi_chan->tre_ring;
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1214
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1215  	buf_info = buf_ring->wp;
> cd116318803f5e drivers/bus/mhi/core/main.c Hemant Kumar          2020-05-21  1216  	WARN_ON(buf_info->used);
> cd116318803f5e drivers/bus/mhi/core/main.c Hemant Kumar          2020-05-21  1217  	buf_info->pre_mapped = info->pre_mapped;
> cd116318803f5e drivers/bus/mhi/core/main.c Hemant Kumar          2020-05-21  1218  	if (info->pre_mapped)
> cd116318803f5e drivers/bus/mhi/core/main.c Hemant Kumar          2020-05-21  1219  		buf_info->p_addr = info->p_addr;
> cd116318803f5e drivers/bus/mhi/core/main.c Hemant Kumar          2020-05-21  1220  	else
> cd116318803f5e drivers/bus/mhi/core/main.c Hemant Kumar          2020-05-21  1221  		buf_info->v_addr = info->v_addr;
> cd116318803f5e drivers/bus/mhi/core/main.c Hemant Kumar          2020-05-21  1222  	buf_info->cb_buf = info->cb_buf;
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1223  	buf_info->wp = tre_ring->wp;
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1224  	buf_info->dir = mhi_chan->dir;
> cd116318803f5e drivers/bus/mhi/core/main.c Hemant Kumar          2020-05-21  1225  	buf_info->len = info->len;
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1226
> cd116318803f5e drivers/bus/mhi/core/main.c Hemant Kumar          2020-05-21  1227  	if (!info->pre_mapped) {
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1228  		ret = mhi_cntrl->map_single(mhi_cntrl, buf_info);
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1229  		if (ret)
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1230  			return ret;
>
> write_unlock_bh(&mhi_chan->lock);
>
> cd116318803f5e drivers/bus/mhi/core/main.c Hemant Kumar          2020-05-21  1231  	}
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1232
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1233  	eob = !!(flags & MHI_EOB);
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1234  	eot = !!(flags & MHI_EOT);
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1235  	chain = !!(flags & MHI_CHAIN);
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1236  	bei = !!(mhi_chan->intmod);
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1237
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1238  	mhi_tre = tre_ring->wp;
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1239  	mhi_tre->ptr = MHI_TRE_DATA_PTR(buf_info->p_addr);
> cd116318803f5e drivers/bus/mhi/core/main.c Hemant Kumar          2020-05-21  1240  	mhi_tre->dword[0] = MHI_TRE_DATA_DWORD0(info->len);
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1241  	mhi_tre->dword[1] = MHI_TRE_DATA_DWORD1(bei, eot, eob, chain);
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1242
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1243  	/* increment WP */
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1244  	mhi_add_ring_element(mhi_cntrl, tre_ring);
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1245  	mhi_add_ring_element(mhi_cntrl, buf_ring);
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1246
> c8a037317010d5 drivers/bus/mhi/host/main.c Bhaumik Bhatt         2023-09-11  1247  	write_unlock_bh(&mhi_chan->lock);
> c8a037317010d5 drivers/bus/mhi/host/main.c Bhaumik Bhatt         2023-09-11  1248
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20 @1249  	return 0;
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1250  }
>