Hi, 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/kiransuren-osuosl-org/Staging-an... base: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git 726eb70e0d34dc4bc4dada71f52bba8ed638431e config: x86_64-randconfig-a006-20201016 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 5fbab4025eb57b12f2842ab188ff07a110708e1d) 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/1496e5f2103cc6f96af90aaf323cf92f0... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review kiransuren-osuosl-org/Staging-android-ashmem-changed-struct-file_operations-to-const-file_operations/20201016-131238 git checkout 1496e5f2103cc6f96af90aaf323cf92f018dcf41 # 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(a)intel.com&gt; All errors (new ones prefixed by >>): static const file_operations vmfile_fops; ^ struct vmfile_fops = *vmfile->f_op; ~~~~~~~~~~~ ^ drivers/staging/android/ashmem.c:379:31: note: variable 'vmfile_fops' declared const here static const 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:379:31: note: variable 'vmfile_fops' declared const here static const 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:379:31: note: variable 'vmfile_fops' declared const here static const file_operations vmfile_fops; ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~ 4 errors generated. vim +379 drivers/staging/android/ashmem.c 376 377 static int ashmem_mmap(struct file *file, struct vm_area_struct *vma) 378 { 380 struct ashmem_area *asma = file->private_data; 381 int ret = 0; 382 383 mutex_lock(&ashmem_mutex); 384 385 /* user needs to SET_SIZE before mapping */ 386 if (!asma->size) { 387 ret = -EINVAL; 388 goto out; 389 } 390 391 /* requested mapping size larger than object size */ 392 if (vma->vm_end - vma->vm_start > PAGE_ALIGN(asma->size)) { 393 ret = -EINVAL; 394 goto out; 395 } 396 397 /* requested protection bits must match our allowed protection mask */ 398 if ((vma->vm_flags & ~calc_vm_prot_bits(asma->prot_mask, 0)) & 399 calc_vm_prot_bits(PROT_MASK, 0)) { 400 ret = -EPERM; 401 goto out; 402 } 403 vma->vm_flags &= ~calc_vm_may_flags(~asma->prot_mask); 404 405 if (!asma->file) { 406 char *name = ASHMEM_NAME_DEF; 407 struct file *vmfile; 408 struct inode *inode; 409 410 if (asma->name[ASHMEM_NAME_PREFIX_LEN] != '\0') 411 name = asma->name; 412 413 /* ... and allocate the backing shmem file */ 414 vmfile = shmem_file_setup(name, asma->size, vma->vm_flags); 415 if (IS_ERR(vmfile)) { 416 ret = PTR_ERR(vmfile); 417 goto out; 418 } 419 vmfile->f_mode |= FMODE_LSEEK; 420 inode = file_inode(vmfile); 421 lockdep_set_class(&inode->i_rwsem, &backing_shmem_inode_class); 422 asma->file = vmfile; 423 /* 424 * override mmap operation of the vmfile so that it can't be 425 * remapped which would lead to creation of a new vma with no 426 * asma permission checks. Have to override get_unmapped_area 427 * as well to prevent VM_BUG_ON check for f_ops modification. 428 */ 429 if (!vmfile_fops.mmap) { 431 vmfile_fops.mmap = ashmem_vmfile_mmap; 432 vmfile_fops.get_unmapped_area = 433 ashmem_vmfile_get_unmapped_area; 434 } 435 vmfile->f_op = &vmfile_fops; 436 } 437 get_file(asma->file); 438 439 /* 440 * XXX - Reworked to use shmem_zero_setup() instead of 441 * shmem_set_file while we're in staging. -jstultz 442 */ 443 if (vma->vm_flags & VM_SHARED) { 444 ret = shmem_zero_setup(vma); 445 if (ret) { 446 fput(asma->file); 447 goto out; 448 } 449 } else { 450 vma_set_anonymous(vma); 451 } 452 453 if (vma->vm_file) 454 fput(vma->vm_file); 455 vma->vm_file = asma->file; 456 457 out: 458 mutex_unlock(&ashmem_mutex); 459 return ret; 460 } 461 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org