Re: [PATCH v3] vfs: avoid delegating to task_work when cleaning up failed open

[Matthew Wilcox <willy@infradead.org>]

On Thu, Sep 28, 2023 at 12:25:16PM +0200, Mateusz Guzik wrote:
> Below is my rebased patch + rewritten commit message with updated bench
> results. I decided to stick to fput_badopen name because with your patch
> it legitimately has to unref. Naming that "release_empty_file" or
> whatever would be rather misleading imho.

Do we still need fput_badopen()?  Couldn't we just make this part of
regular fput() at this point?  ie:

+++ b/fs/file_table.c
@@ -435,6 +435,10 @@ void fput(struct file *file)
        if (atomic_long_dec_and_test(&file->f_count)) {
                struct task_struct *task = current;
 
+               if (!(file->f_mode & FMODE_OPENED)) {
+                       file_free(file);
+                       return;
+               }
                if (likely(!in_interrupt() && !(task->flags & PF_KTHREAD))) {
                        init_task_work(&file->f_rcuhead, ____fput);
                        if (!task_work_add(task, &file->f_rcuhead, TWA_RESUME))