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@xxxxxxxxx>
> > ---
> >   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;