proc_fops: convert drivers/isdn/ to seq_file

Convert code away from ->read_proc/->write_proc interfaces.  Switch to
proc_create()/proc_create_data() which make addition of proc entries
reliable wrt NULL ->proc_fops, NULL ->data and so on.

Problem with ->read_proc et al is described here commit
786d7e1612f0b0adb6046f19b906609e4fe8b1ba "Fix rmmod/read/write races in
/proc entries"

[akpm@linux-foundation.org: CONFIG_PROC_FS=n build fix]
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Signed-off-by: Karsten Keil <keil@b1-systems.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 17 insertions, 38 deletions

diff --git a/drivers/isdn/capi/capidrv.c b/drivers/isdn/capi/capidrv.c
index 66b7d7a86474..bb450152fb74 100644
--- a/drivers/isdn/capi/capidrv.c
+++ b/drivers/isdn/capi/capidrv.c
@@ -24,6 +24,7 @@
 #include <linux/isdn.h>
 #include <linux/isdnif.h>
 #include <linux/proc_fs.h>
+#include <linux/seq_file.h>
 #include <linux/capi.h>
 #include <linux/kernelcapi.h>
 #include <linux/ctype.h>
@@ -2229,59 +2230,37 @@ static void lower_callback(unsigned int cmd, u32 contr, void *data)
  * /proc/capi/capidrv:
  * nrecvctlpkt nrecvdatapkt nsendctlpkt nsenddatapkt
  */
-static int proc_capidrv_read_proc(char *page, char **start, off_t off,
-                                       int count, int *eof, void *data)
+static int capidrv_proc_show(struct seq_file *m, void *v)
 {
-        int len = 0;
-
-        len += sprintf(page+len, "%lu %lu %lu %lu\n",
+        seq_printf(m, "%lu %lu %lu %lu\n",
                         global.ap.nrecvctlpkt,
                         global.ap.nrecvdatapkt,
                         global.ap.nsentctlpkt,
                         global.ap.nsentdatapkt);
-        if (off+count >= len)
-           *eof = 1;
-        if (len < off)
-           return 0;
-        *start = page + off;
-        return ((count < len-off) ? count : len-off);
+        return 0;
+}
+
+static int capidrv_proc_open(struct inode *inode, struct file *file)
+{
+        return single_open(file, capidrv_proc_show, NULL);
 }
 
-static struct procfsentries {
-  char *name;
-  mode_t mode;
-  int (*read_proc)(char *page, char **start, off_t off,
-                                       int count, int *eof, void *data);
-  struct proc_dir_entry *procent;
-} procfsentries[] = {
-   /* { "capi",           S_IFDIR, 0 }, */
-   { "capi/capidrv",      0      , proc_capidrv_read_proc },
+static const struct file_operations capidrv_proc_fops = {
+        .owner          = THIS_MODULE,
+        .open           = capidrv_proc_open,
+        .read           = seq_read,
+        .llseek         = seq_lseek,
+        .release        = single_release,
 };
 
 static void __init proc_init(void)
 {
-    int nelem = ARRAY_SIZE(procfsentries);
-    int i;
-
-    for (i=0; i < nelem; i++) {
-        struct procfsentries *p = procfsentries + i;
-        p->procent = create_proc_entry(p->name, p->mode, NULL);
-        if (p->procent) p->procent->read_proc = p->read_proc;
-    }
+        proc_create("capi/capidrv", 0, NULL, &capidrv_proc_fops);
 }
 
 static void __exit proc_exit(void)
 {
-    int nelem = ARRAY_SIZE(procfsentries);
-    int i;
-
-    for (i=nelem-1; i >= 0; i--) {
-        struct procfsentries *p = procfsentries + i;
-        if (p->procent) {
-           remove_proc_entry(p->name, NULL);
-           p->procent = NULL;
-        }
-    }
+        remove_proc_entry("capi/capidrv", NULL);
 }
 
 static int __init capidrv_init(void)