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

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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

197
fs/proc/proc_misc.c
View File

@@ -249,155 +249,64 @@ static int cpuinfo_open(struct inode *inode, struct file *file)
return seq_open(file, &cpuinfo_op);
}
enum devinfo_states {
CHR_HDR,
CHR_LIST,
BLK_HDR,
BLK_LIST,
DEVINFO_DONE
};
struct devinfo_state {
void *chrdev;
void *blkdev;
unsigned int num_records;
unsigned int cur_record;
enum devinfo_states state;
};
static void *devinfo_start(struct seq_file *f, loff_t *pos)
{
struct devinfo_state *info = f->private;
if (*pos) {
if ((info) && (*pos <= info->num_records))
return info;
return NULL;
}
info = kmalloc(sizeof(*info), GFP_KERNEL);
f->private = info;
info->chrdev = acquire_chrdev_list();
info->blkdev = acquire_blkdev_list();
info->state = CHR_HDR;
info->num_records = count_chrdev_list();
info->num_records += count_blkdev_list();
info->num_records += 2; /* Character and Block headers */
*pos = 1;
info->cur_record = *pos;
return info;
}
static void *devinfo_next(struct seq_file *f, void *v, loff_t *pos)
{
int idummy;
char *ndummy;
struct devinfo_state *info = f->private;
switch (info->state) {
case CHR_HDR:
info->state = CHR_LIST;
(*pos)++;
/*fallthrough*/
case CHR_LIST:
if (get_chrdev_info(info->chrdev,&idummy,&ndummy)) {
/*
* The character dev list is complete
*/
info->state = BLK_HDR;
} else {
info->chrdev = get_next_chrdev(info->chrdev);
}
(*pos)++;
break;
case BLK_HDR:
info->state = BLK_LIST;
(*pos)++;
/*fallthrough*/
case BLK_LIST:
if (get_blkdev_info(info->blkdev,&idummy,&ndummy)) {
/*
* The block dev list is complete
*/
info->state = DEVINFO_DONE;
} else {
info->blkdev = get_next_blkdev(info->blkdev);
}
(*pos)++;
break;
case DEVINFO_DONE:
(*pos)++;
info->cur_record = *pos;
info = NULL;
break;
default:
break;
}
if (info)
info->cur_record = *pos;
return info;
}
static void devinfo_stop(struct seq_file *f, void *v)
{
struct devinfo_state *info = f->private;
if (info) {
release_chrdev_list(info->chrdev);
release_blkdev_list(info->blkdev);
f->private = NULL;
kfree(info);
}
}
static int devinfo_show(struct seq_file *f, void *arg)
{
int major;
char *name;
struct devinfo_state *info = f->private;
switch(info->state) {
case CHR_HDR:
seq_printf(f,"Character devices:\n");
/* fallthrough */
case CHR_LIST:
if (!get_chrdev_info(info->chrdev,&major,&name))
seq_printf(f,"%3d %s\n",major,name);
break;
case BLK_HDR:
seq_printf(f,"\nBlock devices:\n");
/* fallthrough */
case BLK_LIST:
if (!get_blkdev_info(info->blkdev,&major,&name))
seq_printf(f,"%3d %s\n",major,name);
break;
default:
break;
}
return 0;
}
static struct seq_operations devinfo_op = {
.start = devinfo_start,
.next = devinfo_next,
.stop = devinfo_stop,
.show = devinfo_show,
};
static int devinfo_open(struct inode *inode, struct file *file)
{
return seq_open(file, &devinfo_op);
}
static struct file_operations proc_devinfo_operations = {
.open = devinfo_open,
static struct file_operations proc_cpuinfo_operations = {
.open = cpuinfo_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
static struct file_operations proc_cpuinfo_operations = {
.open = cpuinfo_open,
static int devinfo_show(struct seq_file *f, void *v)
{
int i = *(loff_t *) v;
if (i < CHRDEV_MAJOR_HASH_SIZE) {
if (i == 0)
seq_printf(f, "Character devices:\n");
chrdev_show(f, i);
} else {
i -= CHRDEV_MAJOR_HASH_SIZE;
if (i == 0)
seq_printf(f, "\nBlock devices:\n");
blkdev_show(f, i);
}
return 0;
}
static void *devinfo_start(struct seq_file *f, loff_t *pos)
{
if (*pos < (BLKDEV_MAJOR_HASH_SIZE + CHRDEV_MAJOR_HASH_SIZE))
return pos;
return NULL;
}
static void *devinfo_next(struct seq_file *f, void *v, loff_t *pos)
{
(*pos)++;
if (*pos >= (BLKDEV_MAJOR_HASH_SIZE + CHRDEV_MAJOR_HASH_SIZE))
return NULL;
return pos;
}
static void devinfo_stop(struct seq_file *f, void *v)
{
/* Nothing to do */
}
static struct seq_operations devinfo_ops = {
.start = devinfo_start,
.next = devinfo_next,
.stop = devinfo_stop,
.show = devinfo_show
};
static int devinfo_open(struct inode *inode, struct file *filp)
{
return seq_open(filp, &devinfo_ops);
}
static struct file_operations proc_devinfo_operations = {
.open = devinfo_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,