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authorJoe Korty <joe.korty@ccur.com>2006-03-31 02:30:32 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-31 12:18:53 -0800
commit68eef3b4791572ecb70249c7fb145bb3742dd899 (patch)
tree1f61fce839cec8d672ae06a423d46f0a6fcd924d /fs/char_dev.c
parenta2c348fe0117adced11e374329a5ea3f7c43cb41 (diff)
downloadlinux-68eef3b4791572ecb70249c7fb145bb3742dd899.tar.gz
[PATCH] Simplify proc/devices and fix early termination regression
Make baby-simple the code for /proc/devices. Based on the proven design for /proc/interrupts. This also fixes the early-termination regression 2.6.16 introduced, as demonstrated by: # dd if=/proc/devices bs=1 Character devices: 1 mem 27+0 records in 27+0 records out This should also work (but is untested) when /proc/devices >4096 bytes, which I believe is what the original 2.6.16 rewrite fixed. [akpm@osdl.org: cleanups, simplifications] Signed-off-by: Joe Korty <joe.korty@ccur.com> Cc: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'fs/char_dev.c')
-rw-r--r--fs/char_dev.c87
1 files changed, 11 insertions, 76 deletions
diff --git a/fs/char_dev.c b/fs/char_dev.c
index 4e1b849f912..f3418f7a6e9 100644
--- a/fs/char_dev.c
+++ b/fs/char_dev.c
@@ -15,6 +15,7 @@
#include <linux/module.h>
#include <linux/smp_lock.h>
#include <linux/devfs_fs_kernel.h>
+#include <linux/seq_file.h>
#include <linux/kobject.h>
#include <linux/kobj_map.h>
@@ -27,8 +28,6 @@
static struct kobj_map *cdev_map;
-#define MAX_PROBE_HASH 255 /* random */
-
static DEFINE_MUTEX(chrdevs_lock);
static struct char_device_struct {
@@ -39,93 +38,29 @@ static struct char_device_struct {
char name[64];
struct file_operations *fops;
struct cdev *cdev; /* will die */
-} *chrdevs[MAX_PROBE_HASH];
+} *chrdevs[CHRDEV_MAJOR_HASH_SIZE];
/* index in the above */
static inline int major_to_index(int major)
{
- return major % MAX_PROBE_HASH;
-}
-
-struct chrdev_info {
- int index;
- struct char_device_struct *cd;
-};
-
-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)
-{
- mutex_lock(&chrdevs_lock);
- return get_next_chrdev(NULL);
-}
-
-void release_chrdev_list(void *dev)
-{
- mutex_unlock(&chrdevs_lock);
- kfree(dev);
+ return major % CHRDEV_MAJOR_HASH_SIZE;
}
+#ifdef CONFIG_PROC_FS
-int count_chrdev_list(void)
+void chrdev_show(struct seq_file *f, off_t offset)
{
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)
- count++;
+ if (offset < CHRDEV_MAJOR_HASH_SIZE) {
+ mutex_lock(&chrdevs_lock);
+ for (cd = chrdevs[offset]; cd; cd = cd->next)
+ seq_printf(f, "%3d %s\n", cd->major, cd->name);
+ mutex_unlock(&chrdevs_lock);
}
-
- 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;
-}
+#endif /* CONFIG_PROC_FS */
/*
* Register a single major with a specified minor range.