Re: [PATCH 01/22] gpio: protect the list of GPIO devices with SRCU

[kernel test robot <lkp@xxxxxxxxx>]

Hi Bartosz,

kernel test robot noticed the following build warnings:

[auto build test WARNING on brgl/gpio/for-next]
[also build test WARNING on linus/master v6.8-rc2 next-20240131]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Bartosz-Golaszewski/gpio-protect-the-list-of-GPIO-devices-with-SRCU/20240130-205537
base:   https://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux.git gpio/for-next
patch link:    https://lore.kernel.org/r/20240130124828.14678-2-brgl%40bgdev.pl
patch subject: [PATCH 01/22] gpio: protect the list of GPIO devices with SRCU
config: i386-randconfig-141-20240131 (https://download.01.org/0day-ci/archive/20240131/202401311746.be3dlVTg-lkp@xxxxxxxxx/config)
compiler: clang version 17.0.6 (https://github.com/llvm/llvm-project 6009708b4367171ccdbf4b5905cb6a803753fe18)

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@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-kbuild-all/202401311746.be3dlVTg-lkp@xxxxxxxxx/

New smatch warnings:
drivers/gpio/gpiolib.c:4167 gpiod_find_and_request() error: uninitialized symbol 'ret'.
drivers/gpio/gpiolib.c:4181 gpiod_find_and_request() error: uninitialized symbol 'desc'.

Old smatch warnings:
drivers/gpio/gpiolib.c:4184 gpiod_find_and_request() error: uninitialized symbol 'desc'.

vim +/ret +4167 drivers/gpio/gpiolib.c

0eadd36d9123745 Dmitry Torokhov     2022-09-03  4128  
8eb1f71e7acca4f Dmitry Torokhov     2022-11-11  4129  static struct gpio_desc *gpiod_find_and_request(struct device *consumer,
8eb1f71e7acca4f Dmitry Torokhov     2022-11-11  4130  						struct fwnode_handle *fwnode,
8eb1f71e7acca4f Dmitry Torokhov     2022-11-11  4131  						const char *con_id,
8eb1f71e7acca4f Dmitry Torokhov     2022-11-11  4132  						unsigned int idx,
8eb1f71e7acca4f Dmitry Torokhov     2022-11-11  4133  						enum gpiod_flags flags,
8eb1f71e7acca4f Dmitry Torokhov     2022-11-11  4134  						const char *label,
8eb1f71e7acca4f Dmitry Torokhov     2022-11-11  4135  						bool platform_lookup_allowed)
8eb1f71e7acca4f Dmitry Torokhov     2022-11-11  4136  {
ba2dc1cb5491712 Hans de Goede       2022-12-29  4137  	unsigned long lookupflags = GPIO_LOOKUP_FLAGS_DEFAULT;
c122f461ccac0e7 Andy Shevchenko     2023-03-09  4138  	struct gpio_desc *desc;
8eb1f71e7acca4f Dmitry Torokhov     2022-11-11  4139  	int ret;
8eb1f71e7acca4f Dmitry Torokhov     2022-11-11  4140  
1fe5210a1bfba00 Bartosz Golaszewski 2024-01-30  4141  	scoped_guard(srcu, &gpio_devices_srcu) {
1fe5210a1bfba00 Bartosz Golaszewski 2024-01-30  4142  		desc = gpiod_find_by_fwnode(fwnode, consumer, con_id, idx,
1fe5210a1bfba00 Bartosz Golaszewski 2024-01-30  4143  					    &flags, &lookupflags);
8eb1f71e7acca4f Dmitry Torokhov     2022-11-11  4144  		if (gpiod_not_found(desc) && platform_lookup_allowed) {
8eb1f71e7acca4f Dmitry Torokhov     2022-11-11  4145  			/*
1fe5210a1bfba00 Bartosz Golaszewski 2024-01-30  4146  			 * Either we are not using DT or ACPI, or their lookup
1fe5210a1bfba00 Bartosz Golaszewski 2024-01-30  4147  			 * did not return a result. In that case, use platform
1fe5210a1bfba00 Bartosz Golaszewski 2024-01-30  4148  			 * lookup as a fallback.
8eb1f71e7acca4f Dmitry Torokhov     2022-11-11  4149  			 */
1fe5210a1bfba00 Bartosz Golaszewski 2024-01-30  4150  			dev_dbg(consumer,
1fe5210a1bfba00 Bartosz Golaszewski 2024-01-30  4151  				"using lookup tables for GPIO lookup\n");
8eb1f71e7acca4f Dmitry Torokhov     2022-11-11  4152  			desc = gpiod_find(consumer, con_id, idx, &lookupflags);
8eb1f71e7acca4f Dmitry Torokhov     2022-11-11  4153  		}
8eb1f71e7acca4f Dmitry Torokhov     2022-11-11  4154  
8eb1f71e7acca4f Dmitry Torokhov     2022-11-11  4155  		if (IS_ERR(desc)) {
1fe5210a1bfba00 Bartosz Golaszewski 2024-01-30  4156  			dev_dbg(consumer, "No GPIO consumer %s found\n",
1fe5210a1bfba00 Bartosz Golaszewski 2024-01-30  4157  				con_id);
0eadd36d9123745 Dmitry Torokhov     2022-09-03  4158  			return desc;
0eadd36d9123745 Dmitry Torokhov     2022-09-03  4159  		}
0eadd36d9123745 Dmitry Torokhov     2022-09-03  4160  
8eb1f71e7acca4f Dmitry Torokhov     2022-11-11  4161  		/*
8eb1f71e7acca4f Dmitry Torokhov     2022-11-11  4162  		 * If a connection label was passed use that, else attempt to use
8eb1f71e7acca4f Dmitry Torokhov     2022-11-11  4163  		 * the device name as label
8eb1f71e7acca4f Dmitry Torokhov     2022-11-11  4164  		 */
0eadd36d9123745 Dmitry Torokhov     2022-09-03  4165  		ret = gpiod_request(desc, label);
1fe5210a1bfba00 Bartosz Golaszewski 2024-01-30  4166  	}
8eb1f71e7acca4f Dmitry Torokhov     2022-11-11 @4167  	if (ret) {
8eb1f71e7acca4f Dmitry Torokhov     2022-11-11  4168  		if (!(ret == -EBUSY && flags & GPIOD_FLAGS_BIT_NONEXCLUSIVE))
0eadd36d9123745 Dmitry Torokhov     2022-09-03  4169  			return ERR_PTR(ret);
0eadd36d9123745 Dmitry Torokhov     2022-09-03  4170  
8eb1f71e7acca4f Dmitry Torokhov     2022-11-11  4171  		/*
8eb1f71e7acca4f Dmitry Torokhov     2022-11-11  4172  		 * This happens when there are several consumers for
8eb1f71e7acca4f Dmitry Torokhov     2022-11-11  4173  		 * the same GPIO line: we just return here without
8eb1f71e7acca4f Dmitry Torokhov     2022-11-11  4174  		 * further initialization. It is a bit of a hack.
8eb1f71e7acca4f Dmitry Torokhov     2022-11-11  4175  		 * This is necessary to support fixed regulators.
8eb1f71e7acca4f Dmitry Torokhov     2022-11-11  4176  		 *
8eb1f71e7acca4f Dmitry Torokhov     2022-11-11  4177  		 * FIXME: Make this more sane and safe.
8eb1f71e7acca4f Dmitry Torokhov     2022-11-11  4178  		 */
8eb1f71e7acca4f Dmitry Torokhov     2022-11-11  4179  		dev_info(consumer,
8eb1f71e7acca4f Dmitry Torokhov     2022-11-11  4180  			 "nonexclusive access to GPIO for %s\n", con_id);
8eb1f71e7acca4f Dmitry Torokhov     2022-11-11 @4181  		return desc;
8eb1f71e7acca4f Dmitry Torokhov     2022-11-11  4182  	}
8eb1f71e7acca4f Dmitry Torokhov     2022-11-11  4183  
8eb1f71e7acca4f Dmitry Torokhov     2022-11-11  4184  	ret = gpiod_configure_flags(desc, con_id, lookupflags, flags);
0eadd36d9123745 Dmitry Torokhov     2022-09-03  4185  	if (ret < 0) {
8eb1f71e7acca4f Dmitry Torokhov     2022-11-11  4186  		dev_dbg(consumer, "setup of GPIO %s failed\n", con_id);
0eadd36d9123745 Dmitry Torokhov     2022-09-03  4187  		gpiod_put(desc);
0eadd36d9123745 Dmitry Torokhov     2022-09-03  4188  		return ERR_PTR(ret);
0eadd36d9123745 Dmitry Torokhov     2022-09-03  4189  	}
0eadd36d9123745 Dmitry Torokhov     2022-09-03  4190  
9ce4ed5b4db1363 Bartosz Golaszewski 2023-08-21  4191  	gpiod_line_state_notify(desc, GPIOLINE_CHANGED_REQUESTED);
0eadd36d9123745 Dmitry Torokhov     2022-09-03  4192  
0eadd36d9123745 Dmitry Torokhov     2022-09-03  4193  	return desc;
0eadd36d9123745 Dmitry Torokhov     2022-09-03  4194  }
0eadd36d9123745 Dmitry Torokhov     2022-09-03  4195  

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