Input: remove BKL, fix input_open_file() locking (2f2177c8) · Commits · 戴 / test

Holding the BKL in input_open_file seems pointless because it does not protect against updates of input_table, and all open functions from the underlying drivers have proper mutex locking. This makes input_open_file take the input_mutex when accessing the table and no lock when calling into the lower function. Signed-off-by:

Arnd Bergmann <arnd@arndb.de> Acked-by:

Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com> Signed-off-by:

Dmitry Torokhov <dtor@mail.ru>

drivers/input/input.c

+10 −8

Original line number	Diff line number	Diff line
		@@ -1879,35 +1879,37 @@ static int input_open_file(struct inode inode, struct file file)
		const struct file_operations old_fops, new_fops = NULL;
		int err;

		lock_kernel();
		err = mutex_lock_interruptible(&input_mutex);
		if (err)
		return err;

		/* No load-on-demand here? */
		handler = input_table[iminor(inode) >> 5];
		if (!handler \|\| !(new_fops = fops_get(handler->fops))) {
		err = -ENODEV;
		goto out;
		}
		if (handler)
		new_fops = fops_get(handler->fops);

		mutex_unlock(&input_mutex);

		/*
		* That's _really_ odd. Usually NULL ->open means "nothing special",
		* not "no device". Oh, well...
		*/
		if (!new_fops->open) {
		if (!new_fops \|\| !new_fops->open) {
		fops_put(new_fops);
		err = -ENODEV;
		goto out;
		}

		old_fops = file->f_op;
		file->f_op = new_fops;

		err = new_fops->open(inode, file);

		if (err) {
		fops_put(file->f_op);
		file->f_op = fops_get(old_fops);
		}
		fops_put(old_fops);
		out:
		unlock_kernel();
		return err;
		}

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