[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>
diff --git a/fs/proc/proc_misc.c b/fs/proc/proc_misc.c
index ef5a332..5c10ea1 100644
--- a/fs/proc/proc_misc.c
+++ b/fs/proc/proc_misc.c
@@ -249,155 +249,64 @@
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,