On 21/05/2023 14:57, Joan Bruguera Micó wrote: > On 2023/5/3 13:37, Qi Zheng wrote: >>> +void shrinker_debugfs_remove(struct dentry *debugfs_entry, int debugfs_id) >>> +{ >> >> It would be better to add a check: >> >> if (!debugfs_entry) >> return; >> >>> + debugfs_remove_recursive(debugfs_entry); >>> + ida_free(&shrinker_debugfs_ida, debugfs_id); >>> +} > > As a practical matter, both `debugfs_remove_recursive(NULL)` and > `ida_free(_, -1);` are documented as no-ops, see: > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/fs/debugfs/inode.c?id=0dd2a6fb1e34d6dcb96806bc6b111388ad324722#n748 > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=fc82bbf4dede758007763867d0282353c06d1121 > > Sorry for the late reply (the patch already reached the mainline tree). Note that commit 69cb69ea5542 ("ida: Remove assertions that an ID was allocated") currently in linux-next makes ida_free(..., -1) illegal. I see a crash on boot on my test platform (Firefly-RK3288) with linux-next because of this. Qi's suggested change fixes this. I'm not sure whether Matthew's change removing the ((int)id < 0) check was intentional or not. Reinstating that check would also fix the crash. Steve