2022-03-31 18:04:20

by Junwen Wu

Subject: [PATCH v2] char: misc:use DEFINE_PROC_SHOW_ATTRIBUTE micro to simplify misc proc_fops

DEFINE_PROC_SHOW_ATTRIBUTE is used to simply seq_file flow ,so
we can use it to simplify misc proc_fops.

Signed-off-by: wujunwen <[email protected]>
---
V1 -> V2: Fix compile error with no "CONFIG_PROC_FS"

drivers/char/misc.c | 41 ++++++++++++++---------------------------
1 file changed, 14 insertions(+), 27 deletions(-)

diff --git a/drivers/char/misc.c b/drivers/char/misc.c
index ca5141ed5ef3..076b7f08aa7a 100644
--- a/drivers/char/misc.c
+++ b/drivers/char/misc.c
@@ -64,40 +64,23 @@ static DEFINE_MUTEX(misc_mtx);
static DECLARE_BITMAP(misc_minors, DYNAMIC_MINORS);

#ifdef CONFIG_PROC_FS
-static void *misc_seq_start(struct seq_file *seq, loff_t *pos)
-{
- mutex_lock(&misc_mtx);
- return seq_list_start(&misc_list, *pos);
-}

-static void *misc_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+static int misc_show(struct seq_file *seq, void *v)
{
- return seq_list_next(v, &misc_list, pos);
-}
+ const struct miscdevice *p;

-static void misc_seq_stop(struct seq_file *seq, void *v)
-{
+ mutex_lock(&misc_mtx);
+ list_for_each_entry(p, &misc_list, list) {
+ seq_printf(seq, "%3i %s\n", p->minor, p->name ? p->name : "");
+ }
mutex_unlock(&misc_mtx);
-}
-
-static int misc_seq_show(struct seq_file *seq, void *v)
-{
- const struct miscdevice *p = list_entry(v, struct miscdevice, list);
-
- seq_printf(seq, "%3i %s\n", p->minor, p->name ? p->name : "");
return 0;
}

-
-static const struct seq_operations misc_seq_ops = {
- .start = misc_seq_start,
- .next = misc_seq_next,
- .stop = misc_seq_stop,
- .show = misc_seq_show,
-};
+DEFINE_PROC_SHOW_ATTRIBUTE(misc);
#endif

-static int misc_open(struct inode *inode, struct file *file)
+static int misc_fops_open(struct inode *inode, struct file *file)
{
int minor = iminor(inode);
struct miscdevice *c;
@@ -148,7 +131,7 @@ static struct class *misc_class;

static const struct file_operations misc_fops = {
.owner = THIS_MODULE,
- .open = misc_open,
+ .open = misc_fops_open,
.llseek = noop_llseek,
};

@@ -266,9 +249,11 @@ static char *misc_devnode(struct device *dev, umode_t *mode)
static int __init misc_init(void)
{
int err;
+#ifdef CONFIG_PROC_FS
struct proc_dir_entry *ret;

- ret = proc_create_seq("misc", 0, NULL, &misc_seq_ops);
+ ret = proc_create("misc", 0, NULL, &misc_proc_ops);
+#endif
misc_class = class_create(THIS_MODULE, "misc");
err = PTR_ERR(misc_class);
if (IS_ERR(misc_class))
@@ -284,8 +269,10 @@ static int __init misc_init(void)
pr_err("unable to get major %d for misc devices\n", MISC_MAJOR);
class_destroy(misc_class);
fail_remove:
+#ifdef CONFIG_PROC_FS
if (ret)
remove_proc_entry("misc", NULL);
+#endif
return err;
}
subsys_initcall(misc_init);
--
2.25.1

2022-04-25 06:54:39

by Greg Kroah-Hartman

Subject: Re: [PATCH v2] char: misc:use DEFINE_PROC_SHOW_ATTRIBUTE micro to simplify misc proc_fops

On Thu, Mar 31, 2022 at 03:15:57PM +0000, wujunwen wrote:
> @@ -266,9 +249,11 @@ static char *misc_devnode(struct device *dev, umode_t *mode)
> static int __init misc_init(void)
> {
> int err;
> +#ifdef CONFIG_PROC_FS

We do not like putting #ifdefs in .c files. Please remove these, they
should not be needed.

thanks,

greg k-h