Re: [PATCH] staging: android: ashmem: Fixed warning for structure declaration

From: kernel test robot
Date: Mon Dec 28 2020 - 21:31:16 EST


Hi Angshuman,

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/Angshuman-Sengupta/staging-android-ashmem-Fixed-warning-for-structure-declaration/20201227-192757
base: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git 5e60366d56c630e32befce7ef05c569e04391ca3
config: mips-randconfig-r004-20201227 (attached as .config)
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project cee1e7d14f4628d6174b33640d502bff3b54ae45)
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 mips cross compiling tool for clang build
# apt-get install binutils-mips-linux-gnu
# https://github.com/0day-ci/linux/commit/f29b5812159ea6f79fe84fe78780012627211da1
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Angshuman-Sengupta/staging-android-ashmem-Fixed-warning-for-structure-declaration/20201227-192757
git checkout f29b5812159ea6f79fe84fe78780012627211da1
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=mips

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>

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

6d67b0290b4b84c Suren Baghdasaryan 2020-01-27 376
11980c2ac4ccfad Robert Love 2011-12-20 377 static int ashmem_mmap(struct file *file, struct vm_area_struct *vma)
11980c2ac4ccfad Robert Love 2011-12-20 378 {
f29b5812159ea6f Angshuman Sengupta 2020-12-27 379 static const struct file_operations vmfile_fops;
11980c2ac4ccfad Robert Love 2011-12-20 380 struct ashmem_area *asma = file->private_data;
11980c2ac4ccfad Robert Love 2011-12-20 381 int ret = 0;
11980c2ac4ccfad Robert Love 2011-12-20 382
11980c2ac4ccfad Robert Love 2011-12-20 383 mutex_lock(&ashmem_mutex);
11980c2ac4ccfad Robert Love 2011-12-20 384
11980c2ac4ccfad Robert Love 2011-12-20 385 /* user needs to SET_SIZE before mapping */
59848d6aded59a6 Alistair Strachan 2018-06-19 386 if (!asma->size) {
11980c2ac4ccfad Robert Love 2011-12-20 387 ret = -EINVAL;
11980c2ac4ccfad Robert Love 2011-12-20 388 goto out;
11980c2ac4ccfad Robert Love 2011-12-20 389 }
11980c2ac4ccfad Robert Love 2011-12-20 390
8632c614565d0c5 Alistair Strachan 2018-06-19 391 /* requested mapping size larger than object size */
8632c614565d0c5 Alistair Strachan 2018-06-19 392 if (vma->vm_end - vma->vm_start > PAGE_ALIGN(asma->size)) {
11980c2ac4ccfad Robert Love 2011-12-20 393 ret = -EINVAL;
11980c2ac4ccfad Robert Love 2011-12-20 394 goto out;
11980c2ac4ccfad Robert Love 2011-12-20 395 }
11980c2ac4ccfad Robert Love 2011-12-20 396
11980c2ac4ccfad Robert Love 2011-12-20 397 /* requested protection bits must match our allowed protection mask */
59848d6aded59a6 Alistair Strachan 2018-06-19 398 if ((vma->vm_flags & ~calc_vm_prot_bits(asma->prot_mask, 0)) &
59848d6aded59a6 Alistair Strachan 2018-06-19 399 calc_vm_prot_bits(PROT_MASK, 0)) {
11980c2ac4ccfad Robert Love 2011-12-20 400 ret = -EPERM;
11980c2ac4ccfad Robert Love 2011-12-20 401 goto out;
11980c2ac4ccfad Robert Love 2011-12-20 402 }
56f76fc68492af7 Arve Hjønnevåg 2011-12-20 403 vma->vm_flags &= ~calc_vm_may_flags(~asma->prot_mask);
11980c2ac4ccfad Robert Love 2011-12-20 404
11980c2ac4ccfad Robert Love 2011-12-20 405 if (!asma->file) {
11980c2ac4ccfad Robert Love 2011-12-20 406 char *name = ASHMEM_NAME_DEF;
11980c2ac4ccfad Robert Love 2011-12-20 407 struct file *vmfile;
3e338d3c95c735d Suren Baghdasaryan 2020-07-30 408 struct inode *inode;
11980c2ac4ccfad Robert Love 2011-12-20 409
11980c2ac4ccfad Robert Love 2011-12-20 410 if (asma->name[ASHMEM_NAME_PREFIX_LEN] != '\0')
11980c2ac4ccfad Robert Love 2011-12-20 411 name = asma->name;
11980c2ac4ccfad Robert Love 2011-12-20 412
11980c2ac4ccfad Robert Love 2011-12-20 413 /* ... and allocate the backing shmem file */
11980c2ac4ccfad Robert Love 2011-12-20 414 vmfile = shmem_file_setup(name, asma->size, vma->vm_flags);
7f44cb0ba88b40c Viresh Kumar 2015-07-31 415 if (IS_ERR(vmfile)) {
11980c2ac4ccfad Robert Love 2011-12-20 416 ret = PTR_ERR(vmfile);
11980c2ac4ccfad Robert Love 2011-12-20 417 goto out;
11980c2ac4ccfad Robert Love 2011-12-20 418 }
97fbfef6bd59788 Shuxiao Zhang 2017-04-06 419 vmfile->f_mode |= FMODE_LSEEK;
3e338d3c95c735d Suren Baghdasaryan 2020-07-30 420 inode = file_inode(vmfile);
3e338d3c95c735d Suren Baghdasaryan 2020-07-30 421 lockdep_set_class(&inode->i_rwsem, &backing_shmem_inode_class);
11980c2ac4ccfad Robert Love 2011-12-20 422 asma->file = vmfile;
6d67b0290b4b84c Suren Baghdasaryan 2020-01-27 423 /*
6d67b0290b4b84c Suren Baghdasaryan 2020-01-27 424 * override mmap operation of the vmfile so that it can't be
6d67b0290b4b84c Suren Baghdasaryan 2020-01-27 425 * remapped which would lead to creation of a new vma with no
6d67b0290b4b84c Suren Baghdasaryan 2020-01-27 426 * asma permission checks. Have to override get_unmapped_area
6d67b0290b4b84c Suren Baghdasaryan 2020-01-27 427 * as well to prevent VM_BUG_ON check for f_ops modification.
6d67b0290b4b84c Suren Baghdasaryan 2020-01-27 428 */
6d67b0290b4b84c Suren Baghdasaryan 2020-01-27 429 if (!vmfile_fops.mmap) {
6d67b0290b4b84c Suren Baghdasaryan 2020-01-27 @430 vmfile_fops = *vmfile->f_op;
6d67b0290b4b84c Suren Baghdasaryan 2020-01-27 431 vmfile_fops.mmap = ashmem_vmfile_mmap;
6d67b0290b4b84c Suren Baghdasaryan 2020-01-27 432 vmfile_fops.get_unmapped_area =
6d67b0290b4b84c Suren Baghdasaryan 2020-01-27 433 ashmem_vmfile_get_unmapped_area;
6d67b0290b4b84c Suren Baghdasaryan 2020-01-27 434 }
6d67b0290b4b84c Suren Baghdasaryan 2020-01-27 435 vmfile->f_op = &vmfile_fops;
11980c2ac4ccfad Robert Love 2011-12-20 436 }
11980c2ac4ccfad Robert Love 2011-12-20 437 get_file(asma->file);
11980c2ac4ccfad Robert Love 2011-12-20 438
11980c2ac4ccfad Robert Love 2011-12-20 439 /*
11980c2ac4ccfad Robert Love 2011-12-20 440 * XXX - Reworked to use shmem_zero_setup() instead of
11980c2ac4ccfad Robert Love 2011-12-20 441 * shmem_set_file while we're in staging. -jstultz
11980c2ac4ccfad Robert Love 2011-12-20 442 */
11980c2ac4ccfad Robert Love 2011-12-20 443 if (vma->vm_flags & VM_SHARED) {
11980c2ac4ccfad Robert Love 2011-12-20 444 ret = shmem_zero_setup(vma);
11980c2ac4ccfad Robert Love 2011-12-20 445 if (ret) {
11980c2ac4ccfad Robert Love 2011-12-20 446 fput(asma->file);
11980c2ac4ccfad Robert Love 2011-12-20 447 goto out;
11980c2ac4ccfad Robert Love 2011-12-20 448 }
44960f2a7b63e22 John Stultz 2018-07-31 449 } else {
44960f2a7b63e22 John Stultz 2018-07-31 450 vma_set_anonymous(vma);
11980c2ac4ccfad Robert Love 2011-12-20 451 }
11980c2ac4ccfad Robert Love 2011-12-20 452
11980c2ac4ccfad Robert Love 2011-12-20 453 if (vma->vm_file)
11980c2ac4ccfad Robert Love 2011-12-20 454 fput(vma->vm_file);
11980c2ac4ccfad Robert Love 2011-12-20 455 vma->vm_file = asma->file;
11980c2ac4ccfad Robert Love 2011-12-20 456
11980c2ac4ccfad Robert Love 2011-12-20 457 out:
11980c2ac4ccfad Robert Love 2011-12-20 458 mutex_unlock(&ashmem_mutex);
11980c2ac4ccfad Robert Love 2011-12-20 459 return ret;
11980c2ac4ccfad Robert Love 2011-12-20 460 }
11980c2ac4ccfad Robert Love 2011-12-20 461

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