Re: [PATCH v3 3/4] bus: mhi: host: Avoid processing buffer and event of a disable channel

[Dan Carpenter <dan.carpenter@linaro.org>]

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/20231107-151918
base:   https://git.kernel.org/pub/scm/linux/kernel/git/mani/mhi.git mhi-next
patch link:    https://lore.kernel.org/r/1699341365-47737-4-git-send-email-quic_qianyu%40quicinc.com
patch subject: [PATCH v3 3/4] bus: mhi: host: Avoid processing buffer and event of a disable channel
config: x86_64-randconfig-161-20231107 (https://download.01.org/0day-ci/archive/20231108/202311080155.MiyREgoQ-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce: (https://download.01.org/0day-ci/archive/20231108/202311080155.MiyREgoQ-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/202311080155.MiyREgoQ-lkp@intel.com/

smatch warnings:
drivers/bus/mhi/host/main.c:1257 mhi_gen_tre() warn: inconsistent returns '&mhi_chan->lock'.

vim +1257 drivers/bus/mhi/host/main.c

189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1204  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  1205  			struct mhi_buf_info *info, enum mhi_flags flags)
189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1206  {
189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1207  	struct mhi_ring *buf_ring, *tre_ring;
84f5f31f110e5e drivers/bus/mhi/host/main.c Manivannan Sadhasivam 2022-03-01  1208  	struct mhi_ring_element *mhi_tre;
189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1209  	struct mhi_buf_info *buf_info;
189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1210  	int eot, eob, chain, bei;
189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1211  	int ret;
189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1212  
da05b5d43f483c drivers/bus/mhi/host/main.c Bhaumik Bhatt         2023-11-07  1213  	/* Protect accesses for reading and incrementing WP */
da05b5d43f483c drivers/bus/mhi/host/main.c Bhaumik Bhatt         2023-11-07  1214  	write_lock_bh(&mhi_chan->lock);
6025cde6ecb13c drivers/bus/mhi/host/main.c Qiang Yu              2023-11-07  1215  	if (mhi_chan->ch_state != MHI_CH_STATE_ENABLED)
6025cde6ecb13c drivers/bus/mhi/host/main.c Qiang Yu              2023-11-07  1216  		return -EINVAL;

This looks like two people submitted patches on the same day?
We should unlock before returning?

da05b5d43f483c drivers/bus/mhi/host/main.c Bhaumik Bhatt         2023-11-07  1217  
189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1218  	buf_ring = &mhi_chan->buf_ring;
189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1219  	tre_ring = &mhi_chan->tre_ring;
189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1220  
189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1221  	buf_info = buf_ring->wp;
cd116318803f5e drivers/bus/mhi/core/main.c Hemant Kumar          2020-05-21  1222  	WARN_ON(buf_info->used);
cd116318803f5e drivers/bus/mhi/core/main.c Hemant Kumar          2020-05-21  1223  	buf_info->pre_mapped = info->pre_mapped;
cd116318803f5e drivers/bus/mhi/core/main.c Hemant Kumar          2020-05-21  1224  	if (info->pre_mapped)
cd116318803f5e drivers/bus/mhi/core/main.c Hemant Kumar          2020-05-21  1225  		buf_info->p_addr = info->p_addr;
cd116318803f5e drivers/bus/mhi/core/main.c Hemant Kumar          2020-05-21  1226  	else
cd116318803f5e drivers/bus/mhi/core/main.c Hemant Kumar          2020-05-21  1227  		buf_info->v_addr = info->v_addr;
cd116318803f5e drivers/bus/mhi/core/main.c Hemant Kumar          2020-05-21  1228  	buf_info->cb_buf = info->cb_buf;
189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1229  	buf_info->wp = tre_ring->wp;
189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1230  	buf_info->dir = mhi_chan->dir;
cd116318803f5e drivers/bus/mhi/core/main.c Hemant Kumar          2020-05-21  1231  	buf_info->len = info->len;
189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1232  
cd116318803f5e drivers/bus/mhi/core/main.c Hemant Kumar          2020-05-21  1233  	if (!info->pre_mapped) {
189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1234  		ret = mhi_cntrl->map_single(mhi_cntrl, buf_info);
da05b5d43f483c drivers/bus/mhi/host/main.c Bhaumik Bhatt         2023-11-07  1235  		if (ret) {
da05b5d43f483c drivers/bus/mhi/host/main.c Bhaumik Bhatt         2023-11-07  1236  			write_unlock_bh(&mhi_chan->lock);
189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1237  			return ret;
cd116318803f5e drivers/bus/mhi/core/main.c Hemant Kumar          2020-05-21  1238  		}
da05b5d43f483c drivers/bus/mhi/host/main.c Bhaumik Bhatt         2023-11-07  1239  	}
189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1240  
189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1241  	eob = !!(flags & MHI_EOB);
189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1242  	eot = !!(flags & MHI_EOT);
189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1243  	chain = !!(flags & MHI_CHAIN);
189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1244  	bei = !!(mhi_chan->intmod);
189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1245  
189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1246  	mhi_tre = tre_ring->wp;
189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1247  	mhi_tre->ptr = MHI_TRE_DATA_PTR(buf_info->p_addr);
cd116318803f5e drivers/bus/mhi/core/main.c Hemant Kumar          2020-05-21  1248  	mhi_tre->dword[0] = MHI_TRE_DATA_DWORD0(info->len);
189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1249  	mhi_tre->dword[1] = MHI_TRE_DATA_DWORD1(bei, eot, eob, chain);
189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1250  
189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1251  	/* increment WP */
189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1252  	mhi_add_ring_element(mhi_cntrl, tre_ring);
189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1253  	mhi_add_ring_element(mhi_cntrl, buf_ring);
189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1254  
da05b5d43f483c drivers/bus/mhi/host/main.c Bhaumik Bhatt         2023-11-07  1255  	write_unlock_bh(&mhi_chan->lock);
da05b5d43f483c drivers/bus/mhi/host/main.c Bhaumik Bhatt         2023-11-07  1256  
189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20 @1257  	return 0;
189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1258  }

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