linux-kernel - Re: [PATCH] i2c: imx: Remove a useless test in 'i2c_imx_init_recovery

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Date:   Tue, 8 Aug 2017 08:44:46 +0200
From:   Christophe JAILLET <christophe.jaillet@...adoo.fr>
To:     Julia Lawall <julia.lawall@...6.fr>,
        Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
Cc:     wsa@...-dreams.de, linux-i2c@...r.kernel.org,
        linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: Re: [PATCH] i2c: imx: Remove a useless test in
 'i2c_imx_init_recovery_info()'

Le 07/08/2017 à 09:16, Julia Lawall a écrit :
>
> On Mon, 7 Aug 2017, Uwe Kleine-König wrote:
>
>> On Mon, Aug 07, 2017 at 01:49:53AM +0200, Christophe JAILLET wrote:
>>> 'devm_pinctrl_get()' never returns NULL, so this test can be simplified.
>> That's wrong. If CONFIG_PINCTRL is disabled devm_pinctrl_get returns
>> NULL. But I think this shouldn't be considered an error, so your change
>> is right, just the commit log is not.
>>
>>> diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
>>> index 54a47b40546f..7e84662fe1c0 100644
>>> --- a/drivers/i2c/busses/i2c-imx.c
>>> +++ b/drivers/i2c/busses/i2c-imx.c
>>> @@ -997,7 +997,7 @@ static int i2c_imx_init_recovery_info(struct imx_i2c_struct *i2c_imx,
>>>   	struct i2c_bus_recovery_info *rinfo = &i2c_imx->rinfo;
>>>
>>>   	i2c_imx->pinctrl = devm_pinctrl_get(&pdev->dev);
>>> -	if (!i2c_imx->pinctrl || IS_ERR(i2c_imx->pinctrl)) {
>>> +	if (IS_ERR(i2c_imx->pinctrl)) {
>>>   		dev_info(&pdev->dev, "can't get pinctrl, bus recovery not supported\n");
>>>   		return PTR_ERR(i2c_imx->pinctrl);
>>>   	}
>> Side note: I'm not sure, this construct is valid. IIRC PTR_ERR should
>> only be called for values x where IS_ERR(x) is true. Here it is at least
>> surprising that an message hints to a problem but the return code is 0.
>>
>> @Julia: I'm sure coccinelle can find more of those?!
> I only found a few.  Christophe, if you want to fix tem up, please go
> ahead.

Hi Julia,

I've looked quickly at your output, and can't see what could/should be 
done in the spotted cases.
    e100.c: a comment says that 'If it's NULL, then no ucode is 
required', so, the behavior looks ok to me
    chcr_algo.c: function 'create_wr_fn' is passed as a parameter. I've 
no way to make sure of its behavior, so the code could be valid. I won't 
touch it.
    acl.c:  by code inspection, the way the code is written looks valid 
to me. We have NULL if the a call in 'ocfs2_get_acl_nolock' returns 
-ENODATA. Not that strange to return success in this case

So, personally, I won't propose anything on these files. Up to anyone to 
dig further than me.

CJ
> julia
>
> diff -u -p /var/linuxes/linux-next/drivers/net/ethernet/intel/e100.c
> /tmp/nothing/drivers/net/ethernet/intel/e100.c
> --- /var/linuxes/linux-next/drivers/net/ethernet/intel/e100.c
> +++ /tmp/nothing/drivers/net/ethernet/intel/e100.c
> @@ -1370,8 +1370,6 @@ static inline int e100_load_ucode_wait(s
>
>          fw = e100_request_firmware(nic);
>          /* If it's NULL, then no ucode is required */
> -       if (!fw || IS_ERR(fw))
> -               return PTR_ERR(fw);
>
>          if ((err = e100_exec_cb(nic, (void *)fw, e100_setup_ucode)))
>                  netif_err(nic, probe, nic->netdev,
> diff -u -p /var/linuxes/linux-next/drivers/i2c/busses/i2c-imx.c
> /tmp/nothing/drivers/i2c/busses/i2c-imx.c
> --- /var/linuxes/linux-next/drivers/i2c/busses/i2c-imx.c
> +++ /tmp/nothing/drivers/i2c/busses/i2c-imx.c
> @@ -997,9 +997,7 @@ static int i2c_imx_init_recovery_info(st
>          struct i2c_bus_recovery_info *rinfo = &i2c_imx->rinfo;
>
>          i2c_imx->pinctrl = devm_pinctrl_get(&pdev->dev);
> -       if (!i2c_imx->pinctrl || IS_ERR(i2c_imx->pinctrl)) {
>                  dev_info(&pdev->dev, "can't get pinctrl, bus recovery not
> supported\n");
> -               return PTR_ERR(i2c_imx->pinctrl);
>          }
>
>          i2c_imx->pinctrl_pins_default =
> pinctrl_lookup_state(i2c_imx->pinctrl,
> diff -u -p /var/linuxes/linux-next/drivers/crypto/chelsio/chcr_algo.c
> /tmp/nothing/drivers/crypto/chelsio/chcr_algo.c
> --- /var/linuxes/linux-next/drivers/crypto/chelsio/chcr_algo.c
> +++ /tmp/nothing/drivers/crypto/chelsio/chcr_algo.c
> @@ -3159,8 +3159,6 @@ static int chcr_aead_op(struct aead_requ
>          skb = create_wr_fn(req, u_ctx->lldi.rxq_ids[ctx->rx_qidx], size,
>                             op_type);
>
> -       if (IS_ERR(skb) || !skb)
> -               return PTR_ERR(skb);
>
>          skb->dev = u_ctx->lldi.ports[0];
>          set_wr_txq(skb, CPL_PRIORITY_DATA, ctx->tx_qidx);
> diff -u -p /var/linuxes/linux-next/fs/ocfs2/acl.c
> /tmp/nothing/fs/ocfs2/acl.c
> --- /var/linuxes/linux-next/fs/ocfs2/acl.c
> +++ /tmp/nothing/fs/ocfs2/acl.c
> @@ -331,8 +331,6 @@ int ocfs2_acl_chmod(struct inode *inode,
>                  return 0;
>
>          acl = ocfs2_get_acl_nolock(inode, ACL_TYPE_ACCESS, bh);
> -       if (IS_ERR(acl) || !acl)
> -               return PTR_ERR(acl);
>          ret = __posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode);
>          if (ret)
>                  return ret;
>
>
>
>
>
>> Best regards
>> Uwe
>>
>> --
>> Pengutronix e.K.                           | Uwe Kleine-König            |
>> Industrial Linux Solutions                 | http://www.pengutronix.de/  |
>> --
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> >