[PATCH] staging: android: ashmem: Declared file operation with const keyword

kernel test robot lkp at intel.com
Sun Feb 14 04:49:36 UTC 2021


Hi Thais,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on staging/staging-testing]

url:    https://github.com/0day-ci/linux/commits/Thais-Camacho/staging-android-ashmem-Declared-file-operation-with-const-keyword/20210214-103440
base:   https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git 4eb839aef182fccf8995ee439fc2b48d43e45918
config: x86_64-randconfig-a014-20210214 (attached as .config)
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project c9439ca36342fb6013187d0a69aef92736951476)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install x86_64 cross compiling tool for clang build
        # apt-get install binutils-x86-64-linux-gnu
        # https://github.com/0day-ci/linux/commit/32b5e3c9154f059b60686c16a3c3a316f85b6976
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Thais-Camacho/staging-android-ashmem-Declared-file-operation-with-const-keyword/20210214-103440
        git checkout 32b5e3c9154f059b60686c16a3c3a316f85b6976
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp at intel.com>

All errors (new ones prefixed by >>):

>> drivers/staging/android/ashmem.c:430:16: error: cannot assign to variable 'vmfile_fops' with const-qualified type 'const struct file_operations'
                           vmfile_fops = *vmfile->f_op;
                           ~~~~~~~~~~~ ^
   drivers/staging/android/ashmem.c:379:38: note: variable 'vmfile_fops' declared const here
           static const struct file_operations vmfile_fops;
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~
   drivers/staging/android/ashmem.c:431:21: error: cannot assign to variable 'vmfile_fops' with const-qualified type 'const struct file_operations'
                           vmfile_fops.mmap = ashmem_vmfile_mmap;
                           ~~~~~~~~~~~~~~~~ ^
   drivers/staging/android/ashmem.c:379:38: note: variable 'vmfile_fops' declared const here
           static const struct file_operations vmfile_fops;
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~
   drivers/staging/android/ashmem.c:432:34: error: cannot assign to variable 'vmfile_fops' with const-qualified type 'const struct file_operations'
                           vmfile_fops.get_unmapped_area =
                           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^
   drivers/staging/android/ashmem.c:379:38: note: variable 'vmfile_fops' declared const here
           static const struct file_operations vmfile_fops;
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~
   3 errors generated.


vim +430 drivers/staging/android/ashmem.c

6d67b0290b4b84 Suren Baghdasaryan 2020-01-27  376  
11980c2ac4ccfa Robert Love        2011-12-20  377  static int ashmem_mmap(struct file *file, struct vm_area_struct *vma)
11980c2ac4ccfa Robert Love        2011-12-20  378  {
32b5e3c9154f05 Thais Camacho      2021-02-13  379  	static const struct file_operations vmfile_fops;
11980c2ac4ccfa Robert Love        2011-12-20  380  	struct ashmem_area *asma = file->private_data;
11980c2ac4ccfa Robert Love        2011-12-20  381  	int ret = 0;
11980c2ac4ccfa Robert Love        2011-12-20  382  
11980c2ac4ccfa Robert Love        2011-12-20  383  	mutex_lock(&ashmem_mutex);
11980c2ac4ccfa Robert Love        2011-12-20  384  
11980c2ac4ccfa Robert Love        2011-12-20  385  	/* user needs to SET_SIZE before mapping */
59848d6aded59a Alistair Strachan  2018-06-19  386  	if (!asma->size) {
11980c2ac4ccfa Robert Love        2011-12-20  387  		ret = -EINVAL;
11980c2ac4ccfa Robert Love        2011-12-20  388  		goto out;
11980c2ac4ccfa Robert Love        2011-12-20  389  	}
11980c2ac4ccfa Robert Love        2011-12-20  390  
8632c614565d0c Alistair Strachan  2018-06-19  391  	/* requested mapping size larger than object size */
8632c614565d0c Alistair Strachan  2018-06-19  392  	if (vma->vm_end - vma->vm_start > PAGE_ALIGN(asma->size)) {
11980c2ac4ccfa Robert Love        2011-12-20  393  		ret = -EINVAL;
11980c2ac4ccfa Robert Love        2011-12-20  394  		goto out;
11980c2ac4ccfa Robert Love        2011-12-20  395  	}
11980c2ac4ccfa Robert Love        2011-12-20  396  
11980c2ac4ccfa Robert Love        2011-12-20  397  	/* requested protection bits must match our allowed protection mask */
59848d6aded59a Alistair Strachan  2018-06-19  398  	if ((vma->vm_flags & ~calc_vm_prot_bits(asma->prot_mask, 0)) &
59848d6aded59a Alistair Strachan  2018-06-19  399  	    calc_vm_prot_bits(PROT_MASK, 0)) {
11980c2ac4ccfa Robert Love        2011-12-20  400  		ret = -EPERM;
11980c2ac4ccfa Robert Love        2011-12-20  401  		goto out;
11980c2ac4ccfa Robert Love        2011-12-20  402  	}
56f76fc68492af Arve Hjønnevåg     2011-12-20  403  	vma->vm_flags &= ~calc_vm_may_flags(~asma->prot_mask);
11980c2ac4ccfa Robert Love        2011-12-20  404  
11980c2ac4ccfa Robert Love        2011-12-20  405  	if (!asma->file) {
11980c2ac4ccfa Robert Love        2011-12-20  406  		char *name = ASHMEM_NAME_DEF;
11980c2ac4ccfa Robert Love        2011-12-20  407  		struct file *vmfile;
3e338d3c95c735 Suren Baghdasaryan 2020-07-30  408  		struct inode *inode;
11980c2ac4ccfa Robert Love        2011-12-20  409  
11980c2ac4ccfa Robert Love        2011-12-20  410  		if (asma->name[ASHMEM_NAME_PREFIX_LEN] != '\0')
11980c2ac4ccfa Robert Love        2011-12-20  411  			name = asma->name;
11980c2ac4ccfa Robert Love        2011-12-20  412  
11980c2ac4ccfa Robert Love        2011-12-20  413  		/* ... and allocate the backing shmem file */
11980c2ac4ccfa Robert Love        2011-12-20  414  		vmfile = shmem_file_setup(name, asma->size, vma->vm_flags);
7f44cb0ba88b40 Viresh Kumar       2015-07-31  415  		if (IS_ERR(vmfile)) {
11980c2ac4ccfa Robert Love        2011-12-20  416  			ret = PTR_ERR(vmfile);
11980c2ac4ccfa Robert Love        2011-12-20  417  			goto out;
11980c2ac4ccfa Robert Love        2011-12-20  418  		}
97fbfef6bd5978 Shuxiao Zhang      2017-04-06  419  		vmfile->f_mode |= FMODE_LSEEK;
3e338d3c95c735 Suren Baghdasaryan 2020-07-30  420  		inode = file_inode(vmfile);
3e338d3c95c735 Suren Baghdasaryan 2020-07-30  421  		lockdep_set_class(&inode->i_rwsem, &backing_shmem_inode_class);
11980c2ac4ccfa Robert Love        2011-12-20  422  		asma->file = vmfile;
6d67b0290b4b84 Suren Baghdasaryan 2020-01-27  423  		/*
6d67b0290b4b84 Suren Baghdasaryan 2020-01-27  424  		 * override mmap operation of the vmfile so that it can't be
6d67b0290b4b84 Suren Baghdasaryan 2020-01-27  425  		 * remapped which would lead to creation of a new vma with no
6d67b0290b4b84 Suren Baghdasaryan 2020-01-27  426  		 * asma permission checks. Have to override get_unmapped_area
6d67b0290b4b84 Suren Baghdasaryan 2020-01-27  427  		 * as well to prevent VM_BUG_ON check for f_ops modification.
6d67b0290b4b84 Suren Baghdasaryan 2020-01-27  428  		 */
6d67b0290b4b84 Suren Baghdasaryan 2020-01-27  429  		if (!vmfile_fops.mmap) {
6d67b0290b4b84 Suren Baghdasaryan 2020-01-27 @430  			vmfile_fops = *vmfile->f_op;
6d67b0290b4b84 Suren Baghdasaryan 2020-01-27  431  			vmfile_fops.mmap = ashmem_vmfile_mmap;
6d67b0290b4b84 Suren Baghdasaryan 2020-01-27  432  			vmfile_fops.get_unmapped_area =
6d67b0290b4b84 Suren Baghdasaryan 2020-01-27  433  					ashmem_vmfile_get_unmapped_area;
6d67b0290b4b84 Suren Baghdasaryan 2020-01-27  434  		}
6d67b0290b4b84 Suren Baghdasaryan 2020-01-27  435  		vmfile->f_op = &vmfile_fops;
11980c2ac4ccfa Robert Love        2011-12-20  436  	}
11980c2ac4ccfa Robert Love        2011-12-20  437  	get_file(asma->file);
11980c2ac4ccfa Robert Love        2011-12-20  438  
11980c2ac4ccfa Robert Love        2011-12-20  439  	/*
11980c2ac4ccfa Robert Love        2011-12-20  440  	 * XXX - Reworked to use shmem_zero_setup() instead of
11980c2ac4ccfa Robert Love        2011-12-20  441  	 * shmem_set_file while we're in staging. -jstultz
11980c2ac4ccfa Robert Love        2011-12-20  442  	 */
11980c2ac4ccfa Robert Love        2011-12-20  443  	if (vma->vm_flags & VM_SHARED) {
11980c2ac4ccfa Robert Love        2011-12-20  444  		ret = shmem_zero_setup(vma);
11980c2ac4ccfa Robert Love        2011-12-20  445  		if (ret) {
11980c2ac4ccfa Robert Love        2011-12-20  446  			fput(asma->file);
11980c2ac4ccfa Robert Love        2011-12-20  447  			goto out;
11980c2ac4ccfa Robert Love        2011-12-20  448  		}
44960f2a7b63e2 John Stultz        2018-07-31  449  	} else {
44960f2a7b63e2 John Stultz        2018-07-31  450  		vma_set_anonymous(vma);
11980c2ac4ccfa Robert Love        2011-12-20  451  	}
11980c2ac4ccfa Robert Love        2011-12-20  452  
295992fb815e79 Christian König    2020-09-14  453  	vma_set_file(vma, asma->file);
295992fb815e79 Christian König    2020-09-14  454  	/* XXX: merge this with the get_file() above if possible */
295992fb815e79 Christian König    2020-09-14  455  	fput(asma->file);
11980c2ac4ccfa Robert Love        2011-12-20  456  
11980c2ac4ccfa Robert Love        2011-12-20  457  out:
11980c2ac4ccfa Robert Love        2011-12-20  458  	mutex_unlock(&ashmem_mutex);
11980c2ac4ccfa Robert Love        2011-12-20  459  	return ret;
11980c2ac4ccfa Robert Love        2011-12-20  460  }
11980c2ac4ccfa Robert Love        2011-12-20  461  

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
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