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-rw-r--r--fs/char_dev.c58
1 files changed, 41 insertions, 17 deletions
diff --git a/fs/char_dev.c b/fs/char_dev.c
index fb8507f521b2..ebcc8fb3fa66 100644
--- a/fs/char_dev.c
+++ b/fs/char_dev.c
@@ -28,6 +28,8 @@ static struct kobj_map *cdev_map;
static DEFINE_MUTEX(chrdevs_lock);
+#define CHRDEV_MAJOR_HASH_SIZE 255
+
static struct char_device_struct {
struct char_device_struct *next;
unsigned int major;
@@ -49,16 +51,39 @@ void chrdev_show(struct seq_file *f, off_t offset)
{
struct char_device_struct *cd;
- if (offset < CHRDEV_MAJOR_HASH_SIZE) {
- mutex_lock(&chrdevs_lock);
- for (cd = chrdevs[offset]; cd; cd = cd->next)
+ mutex_lock(&chrdevs_lock);
+ for (cd = chrdevs[major_to_index(offset)]; cd; cd = cd->next) {
+ if (cd->major == offset)
seq_printf(f, "%3d %s\n", cd->major, cd->name);
- mutex_unlock(&chrdevs_lock);
}
+ mutex_unlock(&chrdevs_lock);
}
#endif /* CONFIG_PROC_FS */
+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--) {
+ if (chrdevs[i] == NULL)
+ return i;
+ }
+
+ for (i = CHRDEV_MAJOR_DYN_EXT_START;
+ 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)
+ return i;
+ }
+
+ return -EBUSY;
+}
+
/*
* Register a single major with a specified minor range.
*
@@ -84,22 +109,21 @@ __register_chrdev_region(unsigned int major, unsigned int baseminor,
mutex_lock(&chrdevs_lock);
- /* temporary */
if (major == 0) {
- for (i = ARRAY_SIZE(chrdevs)-1; i > 0; i--) {
- if (chrdevs[i] == NULL)
- break;
- }
-
- if (i < CHRDEV_MAJOR_DYN_END)
- pr_warn("CHRDEV \"%s\" major number %d goes below the dynamic allocation range\n",
- name, i);
-
- if (i == 0) {
- ret = -EBUSY;
+ ret = find_dynamic_major();
+ if (ret < 0) {
+ pr_err("CHRDEV \"%s\" dynamic allocation region is full\n",
+ name);
goto out;
}
- major = i;
+ major = ret;
+ }
+
+ if (major >= CHRDEV_MAJOR_MAX) {
+ pr_err("CHRDEV \"%s\" major requested (%d) is greater than the maximum (%d)\n",
+ name, major, CHRDEV_MAJOR_MAX);
+ ret = -EINVAL;
+ goto out;
}
cd->major = major;