[PATCH] Remove lots of IS_ERR_VALUE abuses and compilation warning.

[PATCH] Remove lots of IS_ERR_VALUE abuses and compilation warning.

[Arvind Yadav]

    Passing value in IS_ERR_VALUE() is wrong, as they
    pass an 'int' into a function that takes an 'unsigned long'
    argument. This happens to work because the type is sign-extended
    on 64-bit architectures before it gets converted into an
    unsigned type.

    Passing an 'unsigned short' or 'unsigned int'
    argument into IS_ERR_VALUE() is guaranteed to be broken, as are
    8-bit integers and types that are wider than 'unsigned long'.

    Any user will get compilation warning for that do not pass an
    'unsigned long' argument.

    Commit '287980e49f; - This change is alreday fixes lots of other
    worst abusers.

Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
---
 drivers/soc/fsl/qe/ucc_fast.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/soc/fsl/qe/ucc_fast.c b/drivers/soc/fsl/qe/ucc_fast.c
index a768931..7cc783c 100644
--- a/drivers/soc/fsl/qe/ucc_fast.c
+++ b/drivers/soc/fsl/qe/ucc_fast.c
@@ -268,7 +268,7 @@ int ucc_fast_init(struct ucc_fast_info * uf_info, struct ucc_fast_private ** ucc
 	/* Allocate memory for Tx Virtual Fifo */
 	uccf->ucc_fast_tx_virtual_fifo_base_offset =
 	    qe_muram_alloc(uf_info->utfs, UCC_FAST_VIRT_FIFO_REGS_ALIGNMENT);
-	if (IS_ERR_VALUE(uccf->ucc_fast_tx_virtual_fifo_base_offset)) {
+	if (uccf->ucc_fast_tx_virtual_fifo_base_offset < 0) {
 		printk(KERN_ERR "%s: cannot allocate MURAM for TX FIFO\n",
 			__func__);
 		uccf->ucc_fast_tx_virtual_fifo_base_offset = 0;
@@ -281,7 +281,7 @@ int ucc_fast_init(struct ucc_fast_info * uf_info, struct ucc_fast_private ** ucc
 		qe_muram_alloc(uf_info->urfs +
 			   UCC_FAST_RECEIVE_VIRTUAL_FIFO_SIZE_FUDGE_FACTOR,
 			   UCC_FAST_VIRT_FIFO_REGS_ALIGNMENT);
-	if (IS_ERR_VALUE(uccf->ucc_fast_rx_virtual_fifo_base_offset)) {
+	if (uccf->ucc_fast_rx_virtual_fifo_base_offset < 0) {
 		printk(KERN_ERR "%s: cannot allocate MURAM for RX FIFO\n",
 			__func__);
 		uccf->ucc_fast_rx_virtual_fifo_base_offset = 0;
-- 
1.9.1

Re: Remove lots of IS_ERR_VALUE abuses and compilation warning.

[Guenter Roeck]

On Thu, Jul 07, 2016 at 08:57:29PM +0530, Arvind Yadav wrote:
> Passing value in IS_ERR_VALUE() is wrong, as they
>     pass an 'int' into a function that takes an 'unsigned long'
>     argument. This happens to work because the type is sign-extended
>     on 64-bit architectures before it gets converted into an
>     unsigned type.
> 
>     Passing an 'unsigned short' or 'unsigned int'
>     argument into IS_ERR_VALUE() is guaranteed to be broken, as are
>     8-bit integers and types that are wider than 'unsigned long'.
> 
>     Any user will get compilation warning for that do not pass an
>     'unsigned long' argument.
> 
>     Commit '287980e49f; - This change is alreday fixes lots of other
>     worst abusers.
> 
Couple of generic comments:

- Your patch subject lines don't include the affected drivers/modules.
  As such, most of them will be ignored because maintainers won't realize
  that you are talking with them. Some may ask you to resubmit with proper
  subject lines.
  Commit 287980e49f is different; it addresses the problem in several
  drivers in a single commit.
- If you patch a single file, I think it would be better to adjust the
  description accordingly. In this patch, the offending variable type is
  u32. The patch description is therefore misleading; the code here simply does
  not work.
- When you resubmit a patch, you don't include a version, not a change log.
  This means additional work for maintainers, who have to figure out which
  patch to apply.

Specific comment:

The allocator in question returns -ENOMEM in an unsigned long. This is assigned
to u32. A proper fix would be to assign the return value to an unsigned
long and to use IS_ER_VALUE() to check if it reports an error, and to only
assign it to ucc_fast_rx_virtual_fifo_base_offset if there was no error.

Also, unless I am missing something - since ucc_fast_rx_virtual_fifo_base_offset
is defined as u32, it is somewhat unlikely that it is ever < 0.

Guenter

> Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
> ---
>  drivers/soc/fsl/qe/ucc_fast.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/soc/fsl/qe/ucc_fast.c b/drivers/soc/fsl/qe/ucc_fast.c
> index a768931..7cc783c 100644
> --- a/drivers/soc/fsl/qe/ucc_fast.c
> +++ b/drivers/soc/fsl/qe/ucc_fast.c
> @@ -268,7 +268,7 @@ int ucc_fast_init(struct ucc_fast_info * uf_info, struct ucc_fast_private ** ucc
>  	/* Allocate memory for Tx Virtual Fifo */
>  	uccf->ucc_fast_tx_virtual_fifo_base_offset =
>  	    qe_muram_alloc(uf_info->utfs, UCC_FAST_VIRT_FIFO_REGS_ALIGNMENT);
> -	if (IS_ERR_VALUE(uccf->ucc_fast_tx_virtual_fifo_base_offset)) {
> +	if (uccf->ucc_fast_tx_virtual_fifo_base_offset < 0) {
>  		printk(KERN_ERR "%s: cannot allocate MURAM for TX FIFO\n",
>  			__func__);
>  		uccf->ucc_fast_tx_virtual_fifo_base_offset = 0;
> @@ -281,7 +281,7 @@ int ucc_fast_init(struct ucc_fast_info * uf_info, struct ucc_fast_private ** ucc
>  		qe_muram_alloc(uf_info->urfs +
>  			   UCC_FAST_RECEIVE_VIRTUAL_FIFO_SIZE_FUDGE_FACTOR,
>  			   UCC_FAST_VIRT_FIFO_REGS_ALIGNMENT);
> -	if (IS_ERR_VALUE(uccf->ucc_fast_rx_virtual_fifo_base_offset)) {
> +	if (uccf->ucc_fast_rx_virtual_fifo_base_offset < 0) {
>  		printk(KERN_ERR "%s: cannot allocate MURAM for RX FIFO\n",
>  			__func__);
>  		uccf->ucc_fast_rx_virtual_fifo_base_offset = 0;

Re: Remove lots of IS_ERR_VALUE abuses and compilation warning.

[arvind Yadav]

Yes, You are right,
-Now Return type of 'qe_muram_alloc' is 'unsigned long', That Was trying 
to assigned in ucc_fast_tx_virtual_fifo_base_offset and 
ucc_fast_rx_virtual_fifo_base_offset. These variable are 'unsigned int'. 
So before assignment need a proper type casting.

-Passing value in IS_ERR_VALUE() is wrong. So this is also need a proper 
type casting before passing an argument.

I have done the changes and re-submitted anther patch, Please review It.

Thanks,
Arvind

On Thursday 07 July 2016 09:21 PM, Guenter Roeck wrote:
> On Thu, Jul 07, 2016 at 08:57:29PM +0530, Arvind Yadav wrote:
>> Passing value in IS_ERR_VALUE() is wrong, as they
>>      pass an 'int' into a function that takes an 'unsigned long'
>>      argument. This happens to work because the type is sign-extended
>>      on 64-bit architectures before it gets converted into an
>>      unsigned type.
>>
>>      Passing an 'unsigned short' or 'unsigned int'
>>      argument into IS_ERR_VALUE() is guaranteed to be broken, as are
>>      8-bit integers and types that are wider than 'unsigned long'.
>>
>>      Any user will get compilation warning for that do not pass an
>>      'unsigned long' argument.
>>
>>      Commit '287980e49f; - This change is alreday fixes lots of other
>>      worst abusers.
>>
> Couple of generic comments:
>
> - Your patch subject lines don't include the affected drivers/modules.
>    As such, most of them will be ignored because maintainers won't realize
>    that you are talking with them. Some may ask you to resubmit with proper
>    subject lines.
>    Commit 287980e49f is different; it addresses the problem in several
>    drivers in a single commit.
> - If you patch a single file, I think it would be better to adjust the
>    description accordingly. In this patch, the offending variable type is
>    u32. The patch description is therefore misleading; the code here simply does
>    not work.
> - When you resubmit a patch, you don't include a version, not a change log.
>    This means additional work for maintainers, who have to figure out which
>    patch to apply.
>
> Specific comment:
>
> The allocator in question returns -ENOMEM in an unsigned long. This is assigned
> to u32. A proper fix would be to assign the return value to an unsigned
> long and to use IS_ER_VALUE() to check if it reports an error, and to only
> assign it to ucc_fast_rx_virtual_fifo_base_offset if there was no error.
>
> Also, unless I am missing something - since ucc_fast_rx_virtual_fifo_base_offset
> is defined as u32, it is somewhat unlikely that it is ever < 0.
>
> Guenter
>
>> Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
>> ---
>>   drivers/soc/fsl/qe/ucc_fast.c | 4 ++--
>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/soc/fsl/qe/ucc_fast.c b/drivers/soc/fsl/qe/ucc_fast.c
>> index a768931..7cc783c 100644
>> --- a/drivers/soc/fsl/qe/ucc_fast.c
>> +++ b/drivers/soc/fsl/qe/ucc_fast.c
>> @@ -268,7 +268,7 @@ int ucc_fast_init(struct ucc_fast_info * uf_info, struct ucc_fast_private ** ucc
>>   	/* Allocate memory for Tx Virtual Fifo */
>>   	uccf->ucc_fast_tx_virtual_fifo_base_offset =
>>   	    qe_muram_alloc(uf_info->utfs, UCC_FAST_VIRT_FIFO_REGS_ALIGNMENT);
>> -	if (IS_ERR_VALUE(uccf->ucc_fast_tx_virtual_fifo_base_offset)) {
>> +	if (uccf->ucc_fast_tx_virtual_fifo_base_offset < 0) {
>>   		printk(KERN_ERR "%s: cannot allocate MURAM for TX FIFO\n",
>>   			__func__);
>>   		uccf->ucc_fast_tx_virtual_fifo_base_offset = 0;
>> @@ -281,7 +281,7 @@ int ucc_fast_init(struct ucc_fast_info * uf_info, struct ucc_fast_private ** ucc
>>   		qe_muram_alloc(uf_info->urfs +
>>   			   UCC_FAST_RECEIVE_VIRTUAL_FIFO_SIZE_FUDGE_FACTOR,
>>   			   UCC_FAST_VIRT_FIFO_REGS_ALIGNMENT);
>> -	if (IS_ERR_VALUE(uccf->ucc_fast_rx_virtual_fifo_base_offset)) {
>> +	if (uccf->ucc_fast_rx_virtual_fifo_base_offset < 0) {
>>   		printk(KERN_ERR "%s: cannot allocate MURAM for RX FIFO\n",
>>   			__func__);
>>   		uccf->ucc_fast_rx_virtual_fifo_base_offset = 0;