diff mbox

st: convert DRIVER_ATTR macros to DRIVER_ATTR_RO

Message ID DDB9C85B850785449757F9914A034FCB3F8E9DA4@G4W3219.americas.hpqcorp.net (mailing list archive)
State New, archived
Headers show

Commit Message

Seymour, Shane M June 24, 2015, 6:10 a.m. UTC
Convert DRIVER_ATTR macros to DRIVER_ATTR_RO as requested by
Greg KH. Also switched to using sprintf as nothing printed should
exceed PAGE_SIZE - based on feedback from Greg when implementing
show functions for tape stats.

Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Shane Seymour <shane.seymour@hp.com>
---
This patch was implemented on top of the previous patch to
convert to using driver attr groups.

Resending with [PATCH] at the front since I forgot to add it.
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Comments

Sergey Senozhatsky June 24, 2015, 6:25 a.m. UTC | #1
On (06/24/15 06:10), Seymour, Shane M wrote:
[..]
>  
>  /* The sysfs driver interface. Read-only at the moment */
> -static ssize_t st_try_direct_io_show(struct device_driver *ddp, char *buf)
> +static ssize_t try_direct_io_show(struct device_driver *ddp, char *buf)
>  {
> -	return snprintf(buf, PAGE_SIZE, "%d\n", try_direct_io);
> +	return sprintf(buf, "%d\n", try_direct_io);
>  }

a nitpick,

per Documentation/filesystems/sysfs.txt

:
: - show() should always use scnprintf().
:

  -ss

> -static DRIVER_ATTR(try_direct_io, S_IRUGO, st_try_direct_io_show, NULL);
> +static DRIVER_ATTR_RO(try_direct_io);
>  
> -static ssize_t st_fixed_buffer_size_show(struct device_driver *ddp, char *buf)
> +static ssize_t fixed_buffer_size_show(struct device_driver *ddp, char *buf)
>  {
> -	return snprintf(buf, PAGE_SIZE, "%d\n", st_fixed_buffer_size);
> +	return sprintf(buf, "%d\n", st_fixed_buffer_size);
>  }
> -static DRIVER_ATTR(fixed_buffer_size, S_IRUGO, st_fixed_buffer_size_show, NULL);
> +static DRIVER_ATTR_RO(fixed_buffer_size);
>  
> -static ssize_t st_max_sg_segs_show(struct device_driver *ddp, char *buf)
> +static ssize_t max_sg_segs_show(struct device_driver *ddp, char *buf)
>  {
> -	return snprintf(buf, PAGE_SIZE, "%d\n", st_max_sg_segs);
> +	return sprintf(buf, "%d\n", st_max_sg_segs);
>  }
> -static DRIVER_ATTR(max_sg_segs, S_IRUGO, st_max_sg_segs_show, NULL);
> +static DRIVER_ATTR_RO(max_sg_segs);
>  
> -static ssize_t st_version_show(struct device_driver *ddd, char *buf)
> +static ssize_t version_show(struct device_driver *ddd, char *buf)
>  {
> -	return snprintf(buf, PAGE_SIZE, "[%s]\n", verstr);
> +	return sprintf(buf, "[%s]\n", verstr);
>  }
> -static DRIVER_ATTR(version, S_IRUGO, st_version_show, NULL);
> +static DRIVER_ATTR_RO(version);
>  
>  static struct attribute *st_drv_attrs[] = {
>  	&driver_attr_try_direct_io.attr,
> --
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Greg KH June 24, 2015, 3:08 p.m. UTC | #2
On Wed, Jun 24, 2015 at 03:25:57PM +0900, Sergey Senozhatsky wrote:
> On (06/24/15 06:10), Seymour, Shane M wrote:
> [..]
> >  
> >  /* The sysfs driver interface. Read-only at the moment */
> > -static ssize_t st_try_direct_io_show(struct device_driver *ddp, char *buf)
> > +static ssize_t try_direct_io_show(struct device_driver *ddp, char *buf)
> >  {
> > -	return snprintf(buf, PAGE_SIZE, "%d\n", try_direct_io);
> > +	return sprintf(buf, "%d\n", try_direct_io);
> >  }
> 
> a nitpick,
> 
> per Documentation/filesystems/sysfs.txt
> 
> :
> : - show() should always use scnprintf().
> :

Don't believe everything you read, this change is just fine.

But, you are doing something here that you did not say you were doing in
the changelog, so for that reason, the patch should be redone.

thanks,

greg k-h
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Greg KH June 24, 2015, 3:10 p.m. UTC | #3
On Wed, Jun 24, 2015 at 03:25:57PM +0900, Sergey Senozhatsky wrote:
> On (06/24/15 06:10), Seymour, Shane M wrote:
> [..]
> >  
> >  /* The sysfs driver interface. Read-only at the moment */
> > -static ssize_t st_try_direct_io_show(struct device_driver *ddp, char *buf)
> > +static ssize_t try_direct_io_show(struct device_driver *ddp, char *buf)
> >  {
> > -	return snprintf(buf, PAGE_SIZE, "%d\n", try_direct_io);
> > +	return sprintf(buf, "%d\n", try_direct_io);
> >  }
> 
> a nitpick,
> 
> per Documentation/filesystems/sysfs.txt
> 
> :
> : - show() should always use scnprintf().
> :

That should be rewritten to say, "don't use snprintf(), but scnprintf(),
if you want to.  Otherwise sprintf() should be fine as you obviously are
only returning a single value to userspace"

Or something like that.

thanks,

greg k-h
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Sergey Senozhatsky June 24, 2015, 11:27 p.m. UTC | #4
On (06/24/15 08:10), Greg KH <gregkh@linuxfoundation.org> (gregkh@linuxfoundation.org) wrote:
> On Wed, Jun 24, 2015 at 03:25:57PM +0900, Sergey Senozhatsky wrote:
> > On (06/24/15 06:10), Seymour, Shane M wrote:
> > [..]
> > >  
> > >  /* The sysfs driver interface. Read-only at the moment */
> > > -static ssize_t st_try_direct_io_show(struct device_driver *ddp, char *buf)
> > > +static ssize_t try_direct_io_show(struct device_driver *ddp, char *buf)
> > >  {
> > > -	return snprintf(buf, PAGE_SIZE, "%d\n", try_direct_io);
> > > +	return sprintf(buf, "%d\n", try_direct_io);
> > >  }
> > 
> > a nitpick,
> > 
> > per Documentation/filesystems/sysfs.txt
> > 
> > :
> > : - show() should always use scnprintf().
> > :
> 
> That should be rewritten to say, "don't use snprintf(), but scnprintf(),
> if you want to.  Otherwise sprintf() should be fine as you obviously are
> only returning a single value to userspace"
> 

Sure, that was just a nitpick. For '%d' it's totally fine, I agree.
It was more of a 'do we strictly obey the rules' thing.

	-ss
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diff mbox

Patch

--- a/drivers/scsi/st.c	2015-06-22 20:38:16.061386739 -0500
+++ b/drivers/scsi/st.c	2015-06-23 17:29:03.547867682 -0500
@@ -4427,29 +4427,29 @@  module_exit(exit_st);
 
 
 /* The sysfs driver interface. Read-only at the moment */
-static ssize_t st_try_direct_io_show(struct device_driver *ddp, char *buf)
+static ssize_t try_direct_io_show(struct device_driver *ddp, char *buf)
 {
-	return snprintf(buf, PAGE_SIZE, "%d\n", try_direct_io);
+	return sprintf(buf, "%d\n", try_direct_io);
 }
-static DRIVER_ATTR(try_direct_io, S_IRUGO, st_try_direct_io_show, NULL);
+static DRIVER_ATTR_RO(try_direct_io);
 
-static ssize_t st_fixed_buffer_size_show(struct device_driver *ddp, char *buf)
+static ssize_t fixed_buffer_size_show(struct device_driver *ddp, char *buf)
 {
-	return snprintf(buf, PAGE_SIZE, "%d\n", st_fixed_buffer_size);
+	return sprintf(buf, "%d\n", st_fixed_buffer_size);
 }
-static DRIVER_ATTR(fixed_buffer_size, S_IRUGO, st_fixed_buffer_size_show, NULL);
+static DRIVER_ATTR_RO(fixed_buffer_size);
 
-static ssize_t st_max_sg_segs_show(struct device_driver *ddp, char *buf)
+static ssize_t max_sg_segs_show(struct device_driver *ddp, char *buf)
 {
-	return snprintf(buf, PAGE_SIZE, "%d\n", st_max_sg_segs);
+	return sprintf(buf, "%d\n", st_max_sg_segs);
 }
-static DRIVER_ATTR(max_sg_segs, S_IRUGO, st_max_sg_segs_show, NULL);
+static DRIVER_ATTR_RO(max_sg_segs);
 
-static ssize_t st_version_show(struct device_driver *ddd, char *buf)
+static ssize_t version_show(struct device_driver *ddd, char *buf)
 {
-	return snprintf(buf, PAGE_SIZE, "[%s]\n", verstr);
+	return sprintf(buf, "[%s]\n", verstr);
 }
-static DRIVER_ATTR(version, S_IRUGO, st_version_show, NULL);
+static DRIVER_ATTR_RO(version);
 
 static struct attribute *st_drv_attrs[] = {
 	&driver_attr_try_direct_io.attr,