[PATCH] convert /proc/devices to use seq_file interface

A Christoph suggested that the /proc/devices file be converted to use the
seq_file interface.  This patch does that.

I've obxerved one or two installation that had sufficiently large sans that
they overran the 4k limit on /proc/devices.

Signed-off-by: Neil Horman <nhorman@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 73 insertions, 23 deletions

diff --git a/fs/char_dev.c b/fs/char_dev.c
index 3b1b1eefdbb0..21195c481637 100644
--- a/fs/char_dev.c
+++ b/fs/char_dev.c
@@ -35,7 +35,7 @@ static struct char_device_struct {
         unsigned int major;
         unsigned int baseminor;
         int minorct;
-        const char *name;
+        char name[64];
         struct file_operations *fops;
         struct cdev *cdev;              /* will die */
 } *chrdevs[MAX_PROBE_HASH];
@@ -46,34 +46,84 @@ static inline int major_to_index(int major)
         return major % MAX_PROBE_HASH;
 }
 
-/* get char device names in somewhat random order */
-int get_chrdev_list(char *page)
-{
+struct chrdev_info {
+        int index;
         struct char_device_struct *cd;
-        int i, len;
+};
 
-        len = sprintf(page, "Character devices:\n");
+void *get_next_chrdev(void *dev)
+{
+        struct chrdev_info *info;
 
+        if (dev == NULL) {
+                info = kmalloc(sizeof(*info), GFP_KERNEL);
+                if (!info)
+                        goto out;
+                info->index=0;
+                info->cd = chrdevs[info->index];
+                if (info->cd)
+                        goto out;
+        } else {
+                info = dev;
+        }
+
+        while (info->index < ARRAY_SIZE(chrdevs)) {
+                if (info->cd)
+                        info->cd = info->cd->next;
+                if (info->cd)
+                        goto out;
+                /*
+                 * No devices on this chain, move to the next
+                 */
+                info->index++;
+                info->cd = (info->index < ARRAY_SIZE(chrdevs)) ?
+                        chrdevs[info->index] : NULL;
+                if (info->cd)
+                        goto out;
+        }
+
+out:
+        return info;
+}
+
+void *acquire_chrdev_list(void)
+{
         down(&chrdevs_lock);
+        return get_next_chrdev(NULL);
+}
+
+void release_chrdev_list(void *dev)
+{
+        up(&chrdevs_lock);
+        kfree(dev);
+}
+
+
+int count_chrdev_list(void)
+{
+        struct char_device_struct *cd;
+        int i, count;
+
+        count = 0;
+
         for (i = 0; i < ARRAY_SIZE(chrdevs) ; i++) {
-                for (cd = chrdevs[i]; cd; cd = cd->next) {
-                        /*
-                         * if the current name, plus the 5 extra characters
-                         * in the device line for this entry
-                         * would run us off the page, we're done
-                         */
-                        if ((len+strlen(cd->name) + 5) >= PAGE_SIZE)
-                                goto page_full;
-
-
-                        len += sprintf(page+len, "%3d %s\n",
-                                       cd->major, cd->name);
-                }
+                for (cd = chrdevs[i]; cd; cd = cd->next)
+                        count++;
         }
-page_full:
-        up(&chrdevs_lock);
 
-        return len;
+        return count;
+}
+
+int get_chrdev_info(void *dev, int *major, char **name)
+{
+        struct chrdev_info *info = dev;
+
+        if (info->cd == NULL)
+                return 1;
+
+        *major = info->cd->major;
+        *name = info->cd->name;
+        return 0;
 }
 
 /*
@@ -121,7 +171,7 @@ __register_chrdev_region(unsigned int major, unsigned int baseminor,
         cd->major = major;
         cd->baseminor = baseminor;
         cd->minorct = minorct;
-        cd->name = name;
+        strncpy(cd->name,name, 64);
 
         i = major_to_index(major);