On Thu, Jun 11, 2020 at 05:46:43PM -0700, Mike Kravetz wrote: > The routine is_file_hugepages() checks f_op == hugetlbfs_file_operations > to determine if the file resides in hugetlbfs. This is problematic when > the file is on a union or overlay. Instead, define a new file mode > FMODE_HUGETLBFS which is set when a hugetlbfs file is opened. The mode > can easily be copied to other 'files' derived from the original hugetlbfs > file. > > With this change hugetlbfs_file_operations can be static as it should be. > > There is also a (duplicate) set of shm file operations used for the routine > is_file_shm_hugepages(). Instead of setting/using special f_op's, just > propagate the FMODE_HUGETLBFS mode. This means is_file_shm_hugepages() and > the duplicate f_ops can be removed. > > While cleaning things up, change the name of is_file_hugepages() to > is_file_hugetlbfs(). The term hugepages is a bit ambiguous. I was going to have objections to this before I read it more carefully and realised that the "shm" here is sysvipc and doesn't have anything to do with the huge page support in shmfs. > A subsequent patch will propagate FMODE_HUGETLBFS in overlayfs. > > Suggested-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx> > Signed-off-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx> Reviewed-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> I might have suggested splitting the rename of is_file_hugetlbfs() from the rest of this patch, but I wouldn't resend to change that.
