On Wed, Nov 11, 2020 at 04:53:00PM +0800, yulei zhang wrote: > > ... same here, seeing that you only call that thing from the next two functions > > and you do *not* provide ->mknod() as a method (unsurprisingly - what would > > device nodes do there?) > > > > Thanks for pointing this out. we may need support the mknod method, otherwise > the dev is redundant and need to be removed. I'd suggest turning that into (static) __create_file(....) with static int dmemfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl) { return __create_file(dir, dentry, mode | S_IFREG); } static int dmemfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) { return __create_file(dir, dentry, mode | S_IFDIR); } (i.e. even inc_nlink() of parent folded into that). [snip] > Yes, we seperate the full implementation for dmemfs_file_mmap into > patch 05/35, it > will assign the interfaces to handle the page fault. It would be less confusing to move the introduction of ->mmap() to that patch, then.