Commit 652d703b authored Feb 05, 2018 by Srivatsa S. Bhat Committed by Greg Kroah-Hartman Mar 15, 2018

char_dev: Fix off-by-one bugs in find_dynamic_major()



CHRDEV_MAJOR_DYN_END and CHRDEV_MAJOR_DYN_EXT_END are valid major
numbers. So fix the loop iteration to include them in the search for
free major numbers.

While at it, also remove a redundant if condition ("cd->major != i"),
as it will never be true.

Signed-off-by: Srivatsa S. Bhat <srivatsa@csail.mit.edu>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent bd329f02

fs/char_dev.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -67,18 +67,18 @@ static int find_dynamic_major(void)
		int i;
		struct char_device_struct *cd;

		for (i = ARRAY_SIZE(chrdevs)-1; i > CHRDEV_MAJOR_DYN_END; i--) {
		for (i = ARRAY_SIZE(chrdevs)-1; i >= CHRDEV_MAJOR_DYN_END; i--) {
		if (chrdevs[i] == NULL)
		return i;
		}

		for (i = CHRDEV_MAJOR_DYN_EXT_START;
		i > CHRDEV_MAJOR_DYN_EXT_END; i--) {
		i >= CHRDEV_MAJOR_DYN_EXT_END; i--) {
		for (cd = chrdevs[major_to_index(i)]; cd; cd = cd->next)
		if (cd->major == i)
		break;

		if (cd == NULL \|\| cd->major != i)
		if (cd == NULL)
		return i;
		}