xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

[PATCH] Simplify proc/devices and fix early termination regression

Browse Source 
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>
This commit is contained in:
Joe Korty
2006-03-31 02:30:32 -08:00
committed by Linus Torvalds
parent a2c348fe01
commit 68eef3b479
4 changed files with 79 additions and 323 deletions
Download Patch File Download Diff File Expand all files Collapse all files

87
fs/char_dev.c
View File

@@ -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;
return major % CHRDEV_MAJOR_HASH_SIZE;
}
struct chrdev_info {
int index;
struct char_device_struct *cd;
};
#ifdef CONFIG_PROC_FS
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);
}
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.