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Subject[PATCH 1/2] char_dev: Fix off-by-one bugs in find_dynamic_major()
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From: Srivatsa S. Bhat <srivatsa@csail.mit.edu>

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>
---

fs/char_dev.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/char_dev.c b/fs/char_dev.c
index a65e4a5..33c9385 100644
--- a/fs/char_dev.c
+++ b/fs/char_dev.c
@@ -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;
}

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