[PATCH] lib/cmdline.c: add to the get_options() documentation

[PATCH] lib/cmdline.c: add to the get_options() documentation

[Dan Carpenter]

I wasn't sure how get_options() worked, so I looked at examples.  And by
sheer chance the first example I picked the only example which uses it
incorrectly...  I've added some comments that hopefully help.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

diff --git a/lib/cmdline.c b/lib/cmdline.c
index 4c0888c4a68d..0eb8d0ab60db 100644
--- a/lib/cmdline.c
+++ b/lib/cmdline.c
@@ -73,14 +73,15 @@ EXPORT_SYMBOL(get_option);
 /**
  *	get_options - Parse a string into a list of integers
  *	@str: String to be parsed
- *	@nints: size of integer array
+ *	@nints: size of integer array (including the extra int at the start)
  *	@ints: integer array
  *
  *	This function parses a string containing a comma-separated
  *	list of integers, a hyphen-separated range of _positive_ integers,
  *	or a combination of both.  The parse halts when the array is
  *	full, or when no more numbers can be retrieved from the
- *	string.
+ *	string.  It stores the number of numbers as the first element in the
+ *	array.
  *
  *	Return value is the character in the string which caused
  *	the parse to end (typically a null terminator, if @str is

Re: [PATCH] lib/cmdline.c: add to the get_options() documentation

[Ilya Matveychikov]

> On Aug 21, 2017, at 1:46 PM, Dan Carpenter <dan.carpenter@oracle.com> wrote:
> 
> I wasn't sure how get_options() worked, so I looked at examples.  And by
> sheer chance the first example I picked the only example which uses it
> incorrectly...  I've added some comments that hopefully help.
> 

See also comments on my patch from Ben Hutchings:
https://patchwork.kernel.org/patch/9811617/

Re: [PATCH] lib/cmdline.c: add to the get_options() documentation

[Dan Carpenter]

On Mon, Aug 21, 2017 at 02:42:52PM +0400, Ilya Matveychikov wrote:
> 
> > On Aug 21, 2017, at 1:46 PM, Dan Carpenter <dan.carpenter@oracle.com> wrote:
> > 
> > I wasn't sure how get_options() worked, so I looked at examples.  And by
> > sheer chance the first example I picked the only example which uses it
> > incorrectly...  I've added some comments that hopefully help.
> > 
> 
> See also comments on my patch from Ben Hutchings:
> https://patchwork.kernel.org/patch/9811617/

Ugh...  The implementation of get_options() looks gnarly, yes.  That
affects the part of my comment which says:

+ *     string.  It stores the number of numbers as the first element in the
+ *     array.

If we are going to keep the current behavior then we should specify that
ints[0] can be higher than "nints - 1".  But I feel like the current
behavior is wrong and that get_range() should never return more than n.

regards,
dan carpenter