Commit f649d6d3 authored by Alexey Dobriyan's avatar Alexey Dobriyan Committed by Linus Torvalds
Browse files

proc: simplify locking in remove_proc_entry() 



proc_subdir_lock protects only modifying and walking through PDE lists, so
after we've found PDE to remove and actually removed it from lists, there is
no need to hold proc_subdir_lock for the rest of operation.

Signed-off-by: default avatarAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 638fa202

fs/proc/generic.c

+40 −42
Original line number Diff line number Diff line
@@ -734,21 +734,26 @@ void free_proc_entry(struct proc_dir_entry *de) 
void remove_proc_entry(const char *name, struct proc_dir_entry *parent)

{

	struct proc_dir_entry **p;

	struct proc_dir_entry *de;

	struct proc_dir_entry *de = NULL;

	const char *fn = name;

	int len;



	if (!parent && xlate_proc_name(name, &parent, &fn) != 0)

		goto out;

		return;

	len = strlen(fn);



	spin_lock(&proc_subdir_lock);

	for (p = &parent->subdir; *p; p=&(*p)->next ) {

		if (!proc_match(len, fn, *p))

			continue;

		if (proc_match(len, fn, *p)) {

			de = *p;

			*p = de->next;

			de->next = NULL;

			break;

		}

	}

	spin_unlock(&proc_subdir_lock);

	if (!de)

		return;



	spin_lock(&de->pde_unload_lock);

	/*
@@ -764,11 +769,9 @@ void remove_proc_entry(const char *name, struct proc_dir_entry *parent) 
			de->pde_unload_completion = &c;



		spin_unlock(&de->pde_unload_lock);

			spin_unlock(&proc_subdir_lock);



		wait_for_completion(de->pde_unload_completion);



			spin_lock(&proc_subdir_lock);

		goto continue_removing;

	}

	spin_unlock(&de->pde_unload_lock);
@@ -785,9 +788,4 @@ void remove_proc_entry(const char *name, struct proc_dir_entry *parent) 
	}

	if (atomic_dec_and_test(&de->count))

		free_proc_entry(de);

		break;

	}

	spin_unlock(&proc_subdir_lock);

out:

	return;

}