Re: [PATCH] treewide: remove redundent IS_ERR() before error code check

On Mon, Jan 06, 2020 at 01:58:33PM +0900, Masahiro Yamada wrote:

'PTR_ERR(p) == -E*' is a stronger condition than IS_ERR(p).
Hence, IS_ERR(p) is unneeded.

The semantic patch that generates this commit is as follows:

// <smpl>
@@
expression ptr;
constant error_code;
@@
-IS_ERR(ptr) && (PTR_ERR(ptr) == - error_code)
+PTR_ERR(ptr) == - error_code
// </smpl>

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Any reason for not doing instead:

	ptr == ERR_PTR(-error_code)

?  To me it seems weird to use PTR_ERR() on non-error pointers.  I even had to
double check that it returns a 'long' and not an 'int'.  (If it returned an
'int', it wouldn't work...)

- Eric