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From: Eric Biggers <ebiggers@kernel.org>
To: Masahiro Yamada <masahiroy@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Julia Lawall <julia.lawall@lip6.fr>,
	linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-clk@vger.kernel.org, linux-crypto@vger.kernel.org,
	linux-gpio@vger.kernel.org, linux-i2c@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org,
	netdev@vger.kernel.org, alsa-devel@alsa-project.org,
	devicetree@vger.kernel.org
Subject: Re: [PATCH] treewide: remove redundent IS_ERR() before error code check
Date: Mon, 6 Jan 2020 21:15:21 -0800	[thread overview]
Message-ID: <20200107051521.GF705@sol.localdomain> (raw)
In-Reply-To: <20200106045833.1725-1-masahiroy@kernel.org>

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

  parent reply	other threads:[~2020-01-07  5:15 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-06  4:58 Masahiro Yamada
2020-01-06  6:02 ` Stephen Boyd
2020-01-06  9:38 ` Bartosz Golaszewski
2020-01-06 10:05 ` Wolfram Sang
2020-01-07  5:15 ` Eric Biggers [this message]
2020-01-07  6:28   ` Masahiro Yamada
2020-01-07  9:52 ` Rafael J. Wysocki
2020-01-08 20:17 ` Rob Herring

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