diff options
| -rw-r--r-- | fs/char_dev.c | 28 |
1 files changed, 23 insertions, 5 deletions
diff --git a/fs/char_dev.c b/fs/char_dev.c index 0009346d827f..33b95af89da4 100644 --- a/fs/char_dev.c +++ b/fs/char_dev.c @@ -128,13 +128,31 @@ __register_chrdev_region(unsigned int major, unsigned int baseminor, for (cp = &chrdevs[i]; *cp; cp = &(*cp)->next) if ((*cp)->major > major || - ((*cp)->major == major && (*cp)->baseminor >= baseminor)) + ((*cp)->major == major && + (((*cp)->baseminor >= baseminor) || + ((*cp)->baseminor + (*cp)->minorct > baseminor)))) break; - if (*cp && (*cp)->major == major && - (*cp)->baseminor < baseminor + minorct) { - ret = -EBUSY; - goto out; + + /* Check for overlapping minor ranges. */ + if (*cp && (*cp)->major == major) { + int old_min = (*cp)->baseminor; + int old_max = (*cp)->baseminor + (*cp)->minorct - 1; + int new_min = baseminor; + int new_max = baseminor + minorct - 1; + + /* New driver overlaps from the left. */ + if (new_max >= old_min && new_max <= old_max) { + ret = -EBUSY; + goto out; + } + + /* New driver overlaps from the right. */ + if (new_min <= old_max && new_min >= old_min) { + ret = -EBUSY; + goto out; + } } + cd->next = *cp; *cp = cd; mutex_unlock(&chrdevs_lock); |