fs: make close_range() synchronous

__range_close() closes through filp_close() so every file the caller
held the last reference to is punted to task work. That costs one
cmpxchg per file plus a list entry for any later task_work_cancel() to
search under ->pi_lock. close_range(2) exists to close many descriptors
in one go fast. So convert it to the same synchronous treatment as
close(2) and close_files().

Flush and put each file inline while ->file_lock is dropped.
close_range(2) now behaves like close(2).

Link: https://patch.msgid.link/20260910-work-coredump-unlock-self-v4-7-a5c1800dc930@kernel.org
Reviewed-by: NeilBrown <neil@brown.name>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
This commit is contained in:
Christian Brauner 2026-09-10 17:48:05 +02:00
parent c8d9b40eab
commit 056069eb2b
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@ -911,7 +911,7 @@ static inline void __range_close(struct files_struct *files,
file = file_close_fd_locked(files, fd);
if (file) {
spin_unlock(&files->file_lock);
filp_close(file, files);
filp_close_sync(file, files);
cond_resched();
spin_lock(&files->file_lock);
fdt = files_fdtable(files);