[28/42] drbd: switch to proc_create_single

Message ID 20180516094346.20506-29-hch@lst.de
State Not Applicable
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Series
  • [01/42] net/can: single_open_net needs to be paired with single_release_net
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Commit Message

Christoph Hellwig May 16, 2018, 9:43 a.m.
And stop messing with try_module_get on THIS_MODULE, which doesn't make
any sense here.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/block/drbd/drbd_int.h  |  2 +-
 drivers/block/drbd/drbd_main.c |  3 ++-
 drivers/block/drbd/drbd_proc.c | 34 +---------------------------------
 3 files changed, 4 insertions(+), 35 deletions(-)

Comments

Lars Ellenberg May 18, 2018, 12:55 p.m. | #1
On Wed, May 16, 2018 at 11:43:32AM +0200, Christoph Hellwig wrote:
> And stop messing with try_module_get on THIS_MODULE, which doesn't make
> any sense here.

The idea was to increase module count on /proc/drbd access.

If someone holds /proc/drbd open, previously rmmod would
"succeed" in starting the unload, but then block on remove_proc_entry,
leading to a situation where the lsmod does not show drbd anymore,
but /proc/drbd being still there (but no longer accessible).

I'd rather have rmmod fail up front in this case.
And try_module_get() seemed most appropriate.

    Lars

Patch

diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index 06ecee1b528e..461ddec04e7c 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -1643,7 +1643,7 @@  void drbd_bump_write_ordering(struct drbd_resource *resource, struct drbd_backin
 
 /* drbd_proc.c */
 extern struct proc_dir_entry *drbd_proc;
-extern const struct file_operations drbd_proc_fops;
+int drbd_seq_show(struct seq_file *seq, void *v);
 
 /* drbd_actlog.c */
 extern bool drbd_al_begin_io_prepare(struct drbd_device *device, struct drbd_interval *i);
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 185f1ef00a7c..c2d154faac02 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -3010,7 +3010,8 @@  static int __init drbd_init(void)
 		goto fail;
 
 	err = -ENOMEM;
-	drbd_proc = proc_create_data("drbd", S_IFREG | S_IRUGO , NULL, &drbd_proc_fops, NULL);
+	drbd_proc = proc_create_single("drbd", S_IFREG | S_IRUGO , NULL,
+			drbd_seq_show);
 	if (!drbd_proc)	{
 		pr_err("unable to register proc file\n");
 		goto fail;
diff --git a/drivers/block/drbd/drbd_proc.c b/drivers/block/drbd/drbd_proc.c
index 582caeb0de86..74ef29247bb5 100644
--- a/drivers/block/drbd/drbd_proc.c
+++ b/drivers/block/drbd/drbd_proc.c
@@ -33,18 +33,7 @@ 
 #include <linux/drbd.h>
 #include "drbd_int.h"
 
-static int drbd_proc_open(struct inode *inode, struct file *file);
-static int drbd_proc_release(struct inode *inode, struct file *file);
-
-
 struct proc_dir_entry *drbd_proc;
-const struct file_operations drbd_proc_fops = {
-	.owner		= THIS_MODULE,
-	.open		= drbd_proc_open,
-	.read		= seq_read,
-	.llseek		= seq_lseek,
-	.release	= drbd_proc_release,
-};
 
 static void seq_printf_with_thousands_grouping(struct seq_file *seq, long v)
 {
@@ -235,7 +224,7 @@  static void drbd_syncer_progress(struct drbd_device *device, struct seq_file *se
 	}
 }
 
-static int drbd_seq_show(struct seq_file *seq, void *v)
+int drbd_seq_show(struct seq_file *seq, void *v)
 {
 	int i, prev_i = -1;
 	const char *sn;
@@ -345,24 +334,3 @@  static int drbd_seq_show(struct seq_file *seq, void *v)
 
 	return 0;
 }
-
-static int drbd_proc_open(struct inode *inode, struct file *file)
-{
-	int err;
-
-	if (try_module_get(THIS_MODULE)) {
-		err = single_open(file, drbd_seq_show, NULL);
-		if (err)
-			module_put(THIS_MODULE);
-		return err;
-	}
-	return -ENODEV;
-}
-
-static int drbd_proc_release(struct inode *inode, struct file *file)
-{
-	module_put(THIS_MODULE);
-	return single_release(inode, file);
-}
-
-/* PROC FS stuff end */