Re: [PATCH v2 3/6] KVM: Support poll() on coalesced mmio buffer fds

[kernel test robot <lkp@intel.com>]

Hi Ilias,

kernel test robot noticed the following build warnings:

[auto build test WARNING on kvm/queue]
[also build test WARNING on next-20240719]
[cannot apply to mst-vhost/linux-next linus/master kvm/linux-next v6.10]
[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/Ilias-Stamatis/KVM-Fix-coalesced_mmio_has_room/20240719-034316
base:   https://git.kernel.org/pub/scm/virt/kvm/kvm.git queue
patch link:    https://lore.kernel.org/r/20240718193543.624039-4-ilstam%40amazon.com
patch subject: [PATCH v2 3/6] KVM: Support poll() on coalesced mmio buffer fds
config: x86_64-randconfig-122-20240719 (https://download.01.org/0day-ci/archive/20240720/202407200922.pJAJMVRk-lkp@intel.com/config)
compiler: clang version 18.1.5 (https://github.com/llvm/llvm-project 617a15a9eac96088ae5e9134248d8236e34b91b1)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240720/202407200922.pJAJMVRk-lkp@intel.com/reproduce)

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/202407200922.pJAJMVRk-lkp@intel.com/

sparse warnings: (new ones prefixed by >>)
>> arch/x86/kvm/../../../virt/kvm/coalesced_mmio.c:241:22: sparse: sparse: incorrect type in assignment (different base types) @@     expected restricted __poll_t [usertype] mask @@     got int @@
   arch/x86/kvm/../../../virt/kvm/coalesced_mmio.c:241:22: sparse:     expected restricted __poll_t [usertype] mask
   arch/x86/kvm/../../../virt/kvm/coalesced_mmio.c:241:22: sparse:     got int
   arch/x86/kvm/../../../virt/kvm/coalesced_mmio.c: note: in included file (through include/linux/mmzone.h, include/linux/gfp.h, include/linux/mm.h, ...):
   include/linux/page-flags.h:240:46: sparse: sparse: self-comparison always evaluates to false
   include/linux/page-flags.h:240:46: sparse: sparse: self-comparison always evaluates to false

vim +241 arch/x86/kvm/../../../virt/kvm/coalesced_mmio.c

   231	
   232	static __poll_t coalesced_mmio_buffer_poll(struct file *file, struct poll_table_struct *wait)
   233	{
   234		struct kvm_coalesced_mmio_buffer_dev *dev = file->private_data;
   235		__poll_t mask = 0;
   236	
   237		poll_wait(file, &dev->wait_queue, wait);
   238	
   239		spin_lock(&dev->ring_lock);
   240		if (dev->ring && (READ_ONCE(dev->ring->first) != READ_ONCE(dev->ring->last)))
 > 241			mask = POLLIN | POLLRDNORM;
   242		spin_unlock(&dev->ring_lock);
   243	
   244		return mask;
   245	}
   246	

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