alpha: convert srm code 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> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

alpha: convert srm code 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> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alexey Dobriyan · Linus Torvalds
1 parent 4614a696bd
Showing 1 changed file with 33 additions and 32 deletions Side-by-side Diff
arch/alpha/kernel/srm_env.c
@@ -33,6 +33,7 @@
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/proc_fs.h>
+#include <linux/seq_file.h>
 #include <asm/console.h>
 #include <asm/uaccess.h>
 #include <asm/machvec.h>
  
  
  
  
  
  
  
  
  
  
@@ -79,42 +80,41 @@
 static srm_env_t	srm_numbered_entries[256];
  
  
-static int
-srm_env_read(char *page, char **start, off_t off, int count, int *eof,
-		void *data)
+static int srm_env_proc_show(struct seq_file *m, void *v)
 {
-	int		nbytes;
 	unsigned long	ret;
 	srm_env_t	*entry;
+	char		*page;
  
-	if (off != 0) {
-		*eof = 1;
-		return 0;
-	}
+	entry = (srm_env_t *)m->private;
+	page = (char *)__get_free_page(GFP_USER);
+	if (!page)
+		return -ENOMEM;
  
-	entry	= (srm_env_t *) data;
-	ret	= callback_getenv(entry->id, page, count);
+	ret = callback_getenv(entry->id, page, PAGE_SIZE);
  
 	if ((ret >> 61) == 0) {
-		nbytes = (int) ret;
-		*eof = 1;
+		seq_write(m, page, ret);
+		ret = 0;
 	} else
-		nbytes = -EFAULT;
+		ret = -EFAULT;
+	free_page((unsigned long)page);
+	return ret;
+}
  
-	return nbytes;
+static int srm_env_proc_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, srm_env_proc_show, PDE(inode)->data);
 }
  
-static int
-srm_env_write(struct file *file, const char __user *buffer, unsigned long count,
-		void *data)
+static ssize_t srm_env_proc_write(struct file *file, const char __user *buffer,
+				  size_t count, loff_t *pos)
 {
 	int res;
-	srm_env_t	*entry;
+	srm_env_t	*entry = PDE(file->f_path.dentry->d_inode)->data;
 	char		*buf = (char *) __get_free_page(GFP_USER);
 	unsigned long	ret1, ret2;
  
-	entry = (srm_env_t *) data;
-
 	if (!buf)
 		return -ENOMEM;
  
@@ -140,6 +140,15 @@
 	return res;
 }
  
+static const struct file_operations srm_env_proc_fops = {
+	.owner		= THIS_MODULE,
+	.open		= srm_env_proc_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+	.write		= srm_env_proc_write,
+};
+
 static void
 srm_env_cleanup(void)
 {
  
@@ -245,15 +254,10 @@
 	 */
 	entry = srm_named_entries;
 	while (entry->name && entry->id) {
-		entry->proc_entry = create_proc_entry(entry->name,
-				0644, named_dir);
+		entry->proc_entry = proc_create_data(entry->name, 0644, named_dir,
+						     &srm_env_proc_fops, entry);
 		if (!entry->proc_entry)
 			goto cleanup;
-
-		entry->proc_entry->data		= (void *) entry;
-		entry->proc_entry->read_proc	= srm_env_read;
-		entry->proc_entry->write_proc	= srm_env_write;
-
 		entry++;
 	}
  
  
@@ -264,15 +268,12 @@
 		entry = &srm_numbered_entries[var_num];
 		entry->name = number[var_num];
  
-		entry->proc_entry = create_proc_entry(entry->name,
-				0644, numbered_dir);
+		entry->proc_entry = proc_create_data(entry->name, 0644, numbered_dir,
+						     &srm_env_proc_fops, entry);
 		if (!entry->proc_entry)
 			goto cleanup;
  
 		entry->id			= var_num;
-		entry->proc_entry->data		= (void *) entry;
-		entry->proc_entry->read_proc	= srm_env_read;
-		entry->proc_entry->write_proc	= srm_env_write;
 	}
  
 	printk(KERN_INFO "%s: version %s loaded successfully\n", NAME,
...	...	@@ -33,6 +33,7 @@
33	33	#include <linux/module.h>
34	34	#include <linux/init.h>
35	35	#include <linux/proc_fs.h>
	36	+#include <linux/seq_file.h>
36	37	#include <asm/console.h>
37	38	#include <asm/uaccess.h>
38	39	#include <asm/machvec.h>
39	40
40	41
41	42
42	43
43	44
44	45
45	46
46	47
47	48
48	49
...	...	@@ -79,42 +80,41 @@
79	80	static srm_env_t srm_numbered_entries[256];
80	81
81	82
82		-static int
83		-srm_env_read(char page, char start, off_t off, int count, int eof,
84		- void *data)
	83	+static int srm_env_proc_show(struct seq_file m, void v)
85	84	{
86		- int nbytes;
87	85	unsigned long ret;
88	86	srm_env_t *entry;
	87	+ char *page;
89	88
90		- if (off != 0) {
91		- *eof = 1;
92		- return 0;
93		- }
	89	+ entry = (srm_env_t *)m->private;
	90	+ page = (char *)__get_free_page(GFP_USER);
	91	+ if (!page)
	92	+ return -ENOMEM;
94	93
95		- entry = (srm_env_t *) data;
96		- ret = callback_getenv(entry->id, page, count);
	94	+ ret = callback_getenv(entry->id, page, PAGE_SIZE);
97	95
98	96	if ((ret >> 61) == 0) {
99		- nbytes = (int) ret;
100		- *eof = 1;
	97	+ seq_write(m, page, ret);
	98	+ ret = 0;
101	99	} else
102		- nbytes = -EFAULT;
	100	+ ret = -EFAULT;
	101	+ free_page((unsigned long)page);
	102	+ return ret;
	103	+}
103	104
104		- return nbytes;
	105	+static int srm_env_proc_open(struct inode inode, struct file file)
	106	+{
	107	+ return single_open(file, srm_env_proc_show, PDE(inode)->data);
105	108	}
106	109
107		-static int
108		-srm_env_write(struct file file, const char __user buffer, unsigned long count,
109		- void *data)
	110	+static ssize_t srm_env_proc_write(struct file file, const char __user buffer,
	111	+ size_t count, loff_t *pos)
110	112	{
111	113	int res;
112		- srm_env_t *entry;
	114	+ srm_env_t *entry = PDE(file->f_path.dentry->d_inode)->data;
113	115	char buf = (char ) __get_free_page(GFP_USER);
114	116	unsigned long ret1, ret2;
115	117
116		- entry = (srm_env_t *) data;
117		-
118	118	if (!buf)
119	119	return -ENOMEM;
120	120
...	...	@@ -140,6 +140,15 @@
140	140	return res;
141	141	}
142	142
	143	+static const struct file_operations srm_env_proc_fops = {
	144	+ .owner = THIS_MODULE,
	145	+ .open = srm_env_proc_open,
	146	+ .read = seq_read,
	147	+ .llseek = seq_lseek,
	148	+ .release = single_release,
	149	+ .write = srm_env_proc_write,
	150	+};
	151	+
143	152	static void
144	153	srm_env_cleanup(void)
145	154	{
146	155
...	...	@@ -245,15 +254,10 @@
245	254	*/
246	255	entry = srm_named_entries;
247	256	while (entry->name && entry->id) {
248		- entry->proc_entry = create_proc_entry(entry->name,
249		- 0644, named_dir);
	257	+ entry->proc_entry = proc_create_data(entry->name, 0644, named_dir,
	258	+ &srm_env_proc_fops, entry);
250	259	if (!entry->proc_entry)
251	260	goto cleanup;
252		-
253		- entry->proc_entry->data = (void *) entry;
254		- entry->proc_entry->read_proc = srm_env_read;
255		- entry->proc_entry->write_proc = srm_env_write;
256		-
257	261	entry++;
258	262	}
259	263
260	264
...	...	@@ -264,15 +268,12 @@
264	268	entry = &srm_numbered_entries[var_num];
265	269	entry->name = number[var_num];
266	270
267		- entry->proc_entry = create_proc_entry(entry->name,
268		- 0644, numbered_dir);
	271	+ entry->proc_entry = proc_create_data(entry->name, 0644, numbered_dir,
	272	+ &srm_env_proc_fops, entry);
269	273	if (!entry->proc_entry)
270	274	goto cleanup;
271	275
272	276	entry->id = var_num;
273		- entry->proc_entry->data = (void *) entry;
274		- entry->proc_entry->read_proc = srm_env_read;
275		- entry->proc_entry->write_proc = srm_env_write;
276	277	}
277	278
278	279	printk(KERN_INFO "%s: version %s loaded successfully\n", NAME,