parisc: convert /proc/pdc/{lcd,led} 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" Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Grant Grundler <grundler@parisc-linux.org> Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>

parisc: convert /proc/pdc/{lcd,led} 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" Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Grant Grundler <grundler@parisc-linux.org> Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>
Alexey Dobriyan · Kyle McMartin
1 parent 05920797ca
Showing 1 changed file with 29 additions and 30 deletions Side-by-side Diff
drivers/parisc/led.c
@@ -38,6 +38,7 @@
 #include <linux/kernel_stat.h>
 #include <linux/reboot.h>
 #include <linux/proc_fs.h>
+#include <linux/seq_file.h>
 #include <linux/ctype.h>
 #include <linux/blkdev.h>
 #include <linux/workqueue.h>
  
  
  
  
  
  
  
  
@@ -147,41 +148,34 @@
 static void (*led_func_ptr) (unsigned char) __read_mostly;
  
 #ifdef CONFIG_PROC_FS
-static int led_proc_read(char *page, char **start, off_t off, int count, 
-	int *eof, void *data)
+static int led_proc_show(struct seq_file *m, void *v)
 {
-	char *out = page;
-	int len;
-
-	switch ((long)data)
+	switch ((long)m->private)
 	{
 	case LED_NOLCD:
-		out += sprintf(out, "Heartbeat: %d\n", led_heartbeat);
-		out += sprintf(out, "Disk IO: %d\n", led_diskio);
-		out += sprintf(out, "LAN Rx/Tx: %d\n", led_lanrxtx);
+		seq_printf(m, "Heartbeat: %d\n", led_heartbeat);
+		seq_printf(m, "Disk IO: %d\n", led_diskio);
+		seq_printf(m, "LAN Rx/Tx: %d\n", led_lanrxtx);
 		break;
 	case LED_HASLCD:
-		out += sprintf(out, "%s\n", lcd_text);
+		seq_printf(m, "%s\n", lcd_text);
 		break;
 	default:
-		*eof = 1;
 		return 0;
 	}
+	return 0;
+}
  
-	len = out - page - off;
-	if (len < count) {
-		*eof = 1;
-		if (len <= 0) return 0;
-	} else {
-		len = count;
-	}
-	*start = page + off;
-	return len;
+static int led_proc_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, led_proc_show, PDE(inode)->data);
 }
  
-static int led_proc_write(struct file *file, const char *buf, 
-	unsigned long count, void *data)
+
+static ssize_t led_proc_write(struct file *file, const char *buf,
+	size_t count, loff_t *pos)
 {
+	void *data = PDE(file->f_path.dentry->d_inode)->data;
 	char *cur, lbuf[count + 1];
 	int d;
  
@@ -234,6 +228,15 @@
 	return -EINVAL;
 }
  
+static const struct file_operations led_proc_fops = {
+	.owner		= THIS_MODULE,
+	.open		= led_proc_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+	.write		= led_proc_write,
+};
+
 static int __init led_create_procfs(void)
 {
 	struct proc_dir_entry *proc_pdc_root = NULL;
  
  
  
@@ -243,19 +246,15 @@
  
 	proc_pdc_root = proc_mkdir("pdc", 0);
 	if (!proc_pdc_root) return -1;
-	ent = create_proc_entry("led", S_IFREG|S_IRUGO|S_IWUSR, proc_pdc_root);
+	ent = proc_create_data("led", S_IRUGO|S_IWUSR, proc_pdc_root,
+				&led_proc_fops, (void *)LED_NOLCD); /* LED */
 	if (!ent) return -1;
-	ent->data = (void *)LED_NOLCD; /* LED */
-	ent->read_proc = led_proc_read;
-	ent->write_proc = led_proc_write;
  
 	if (led_type == LED_HASLCD)
 	{
-		ent = create_proc_entry("lcd", S_IFREG|S_IRUGO|S_IWUSR, proc_pdc_root);
+		ent = proc_create_data("lcd", S_IRUGO|S_IWUSR, proc_pdc_root,
+					&led_proc_fops, (void *)LED_HASLCD); /* LCD */
 		if (!ent) return -1;
-		ent->data = (void *)LED_HASLCD; /* LCD */
-		ent->read_proc = led_proc_read;
-		ent->write_proc = led_proc_write;
 	}
  
 	return 0;
...	...	@@ -38,6 +38,7 @@
38	38	#include <linux/kernel_stat.h>
39	39	#include <linux/reboot.h>
40	40	#include <linux/proc_fs.h>
	41	+#include <linux/seq_file.h>
41	42	#include <linux/ctype.h>
42	43	#include <linux/blkdev.h>
43	44	#include <linux/workqueue.h>
44	45
45	46
46	47
47	48
48	49
49	50
50	51
51	52
...	...	@@ -147,41 +148,34 @@
147	148	static void (*led_func_ptr) (unsigned char) __read_mostly;
148	149
149	150	#ifdef CONFIG_PROC_FS
150		-static int led_proc_read(char page, char *start, off_t off, int count,
151		- int eof, void data)
	151	+static int led_proc_show(struct seq_file m, void v)
152	152	{
153		- char *out = page;
154		- int len;
155		-
156		- switch ((long)data)
	153	+ switch ((long)m->private)
157	154	{
158	155	case LED_NOLCD:
159		- out += sprintf(out, "Heartbeat: %d\n", led_heartbeat);
160		- out += sprintf(out, "Disk IO: %d\n", led_diskio);
161		- out += sprintf(out, "LAN Rx/Tx: %d\n", led_lanrxtx);
	156	+ seq_printf(m, "Heartbeat: %d\n", led_heartbeat);
	157	+ seq_printf(m, "Disk IO: %d\n", led_diskio);
	158	+ seq_printf(m, "LAN Rx/Tx: %d\n", led_lanrxtx);
162	159	break;
163	160	case LED_HASLCD:
164		- out += sprintf(out, "%s\n", lcd_text);
	161	+ seq_printf(m, "%s\n", lcd_text);
165	162	break;
166	163	default:
167		- *eof = 1;
168	164	return 0;
169	165	}
	166	+ return 0;
	167	+}
170	168
171		- len = out - page - off;
172		- if (len < count) {
173		- *eof = 1;
174		- if (len <= 0) return 0;
175		- } else {
176		- len = count;
177		- }
178		- *start = page + off;
179		- return len;
	169	+static int led_proc_open(struct inode inode, struct file file)
	170	+{
	171	+ return single_open(file, led_proc_show, PDE(inode)->data);
180	172	}
181	173
182		-static int led_proc_write(struct file file, const char buf,
183		- unsigned long count, void *data)
	174	+
	175	+static ssize_t led_proc_write(struct file file, const char buf,
	176	+ size_t count, loff_t *pos)
184	177	{
	178	+ void *data = PDE(file->f_path.dentry->d_inode)->data;
185	179	char *cur, lbuf[count + 1];
186	180	int d;
187	181
...	...	@@ -234,6 +228,15 @@
234	228	return -EINVAL;
235	229	}
236	230
	231	+static const struct file_operations led_proc_fops = {
	232	+ .owner = THIS_MODULE,
	233	+ .open = led_proc_open,
	234	+ .read = seq_read,
	235	+ .llseek = seq_lseek,
	236	+ .release = single_release,
	237	+ .write = led_proc_write,
	238	+};
	239	+
237	240	static int __init led_create_procfs(void)
238	241	{
239	242	struct proc_dir_entry *proc_pdc_root = NULL;
240	243
241	244
242	245
...	...	@@ -243,19 +246,15 @@
243	246
244	247	proc_pdc_root = proc_mkdir("pdc", 0);
245	248	if (!proc_pdc_root) return -1;
246		- ent = create_proc_entry("led", S_IFREG\|S_IRUGO\|S_IWUSR, proc_pdc_root);
	249	+ ent = proc_create_data("led", S_IRUGO\|S_IWUSR, proc_pdc_root,
	250	+ &led_proc_fops, (void )LED_NOLCD); / LED */
247	251	if (!ent) return -1;
248		- ent->data = (void )LED_NOLCD; / LED */
249		- ent->read_proc = led_proc_read;
250		- ent->write_proc = led_proc_write;
251	252
252	253	if (led_type == LED_HASLCD)
253	254	{
254		- ent = create_proc_entry("lcd", S_IFREG\|S_IRUGO\|S_IWUSR, proc_pdc_root);
	255	+ ent = proc_create_data("lcd", S_IRUGO\|S_IWUSR, proc_pdc_root,
	256	+ &led_proc_fops, (void )LED_HASLCD); / LCD */
255	257	if (!ent) return -1;
256		- ent->data = (void )LED_HASLCD; / LCD */
257		- ent->read_proc = led_proc_read;
258		- ent->write_proc = led_proc_write;
259	258	}
260	259
261	260	return 0;