Hi Yizhen, FYI, the error/warning still remains. tree: https://gitee.com/openeuler/kernel.git OLK-5.10 head: b670dd901cbbf97745380d373b1d2607b3235590 commit: cd637a6dded9c0dce5f8d79898bb25be2edb927a [24518/30000] ub: uburma support open/release file ops config: arm64-randconfig-003-20240312 (https://download.01.org/0day-ci/archive/20240324/202403242235.dk8Ti59s-lkp@i...) compiler: aarch64-linux-gcc (GCC) 13.2.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240324/202403242235.dk8Ti59s-lkp@i...) 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> | Closes: https://lore.kernel.org/oe-kbuild-all/202403242235.dk8Ti59s-lkp@intel.com/ All warnings (new ones prefixed by >>):

...

drivers/ub/urma/uburma/uburma_dev_ops.c:32:6: warning: no previous prototype for 'uburma_release_file' [-Wmissing-prototypes] 32 | void uburma_release_file(struct kref *ref) | ^~~~~~~~~~~~~~~~~~~ drivers/ub/urma/uburma/uburma_dev_ops.c:49:5: warning: no previous prototype for 'uburma_open' [-Wmissing-prototypes] 49 | int uburma_open(struct inode *inode, struct file *filp) | ^~~~~~~~~~~ drivers/ub/urma/uburma/uburma_dev_ops.c: In function 'uburma_open': drivers/ub/urma/uburma/uburma_dev_ops.c:66:50: warning: the comparison will always evaluate as 'false' for the address of 'dev_name' will never be NULL [-Waddress] 66 | if (ubc_dev == NULL || ubc_dev->dev_name == NULL) { | ^~ In file included from drivers/ub/urma/uburma/uburma_dev_ops.c:25: include/urma/ubcore_types.h:1589:14: note: 'dev_name' declared here 1589 | char dev_name[UBCORE_MAX_DEV_NAME]; | ^~~~~~~~ drivers/ub/urma/uburma/uburma_dev_ops.c: At top level: drivers/ub/urma/uburma/uburma_dev_ops.c:102:5: warning: no previous prototype for 'uburma_close' [-Wmissing-prototypes] 102 | int uburma_close(struct inode *inode, struct file *filp) | ^~~~~~~~~~~~

vim +/uburma_release_file +32 drivers/ub/urma/uburma/uburma_dev_ops.c 31

32 void uburma_release_file(struct kref *ref) 33 { 34 struct uburma_file *file = container_of(ref, struct uburma_file, ref); 35 int srcu_idx; 36 37 srcu_idx = srcu_read_lock(&file->ubu_dev->ubc_dev_srcu); 38 srcu_dereference(file->ubu_dev->ubc_dev, &file->ubu_dev->ubc_dev_srcu); 39 40 srcu_read_unlock(&file->ubu_dev->ubc_dev_srcu, srcu_idx); 41 42 if (atomic_dec_and_test(&file->ubu_dev->refcnt)) 43 complete(&file->ubu_dev->comp); 44 45 kobject_put(&file->ubu_dev->kobj); 46 kfree(file); 47 } 48 49 int uburma_open(struct inode *inode, struct file *filp) 50 { 51 struct uburma_device *ubu_dev; 52 struct ubcore_device *ubc_dev; 53 struct uburma_file *file; 54 int srcu_idx; 55 int ret; 56 57 ubu_dev = container_of(inode->i_cdev, struct uburma_device, cdev); 58 if (!atomic_inc_not_zero(&ubu_dev->refcnt)) { 59 uburma_log_err("device was not ready.\n"); 60 return -ENXIO; 61 } 62 63 srcu_idx = srcu_read_lock(&ubu_dev->ubc_dev_srcu); 64 mutex_lock(&ubu_dev->lists_mutex); 65 ubc_dev = srcu_dereference(ubu_dev->ubc_dev, &ubu_dev->ubc_dev_srcu); 66 if (ubc_dev == NULL || ubc_dev->dev_name == NULL) { 67 uburma_log_err("can not find ubcore device.\n"); 68 ret = EIO; 69 goto err; 70 } 71 72 file = kzalloc(sizeof(struct uburma_file), GFP_KERNEL); 73 if (!file) { 74 ret = -ENOMEM; 75 uburma_log_err("can not alloc memory.\n"); 76 goto err; 77 } 78 79 file->ubu_dev = ubu_dev; 80 file->ucontext = NULL; 81 kref_init(&file->ref); 82 mutex_init(&file->mutex); 83 filp->private_data = file; 84 85 list_add_tail(&file->list, &ubu_dev->uburma_file_list); 86 kobject_get(&ubu_dev->kobj); // Increase reference count for file. 87 88 mutex_unlock(&ubu_dev->lists_mutex); 89 srcu_read_unlock(&ubu_dev->ubc_dev_srcu, srcu_idx); 90 91 uburma_log_info("device: %s open succeed.\n", ubc_dev->dev_name); 92 return nonseekable_open(inode, filp); 93 94 err: 95 mutex_unlock(&ubu_dev->lists_mutex); 96 srcu_read_unlock(&ubu_dev->ubc_dev_srcu, srcu_idx); 97 if (atomic_dec_and_test(&ubu_dev->refcnt)) 98 complete(&ubu_dev->comp); 99 return ret; 100 } 101 102 int uburma_close(struct inode *inode, struct file *filp)

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