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SubjectRe: [PATCH] for_each macros correctness
On Sun, Jan 26, 2014 at 08:54:18AM -0200, Jose Alonso wrote:
>
> I observed that there are for_each macros that do an extra memory access
> beyond the defined area.
> Normally this does not cause problems.
> But, this can cause exceptions. For example: if the area is allocated at
> the end of a page and the next page is not accessible.
>
> For correctness, I suggest changing the arguments of the 'for loop' like
> others 'for_each' do in the kernel.
>
> files involved:
> drivers/s390/cio/qdio.h
> drivers/scsi/isci/host.h
> drivers/sh/clk/core.c
> include/linux/blk-mq.h
> include/linux/shdma-base.h
> sound/soc/sh/rcar/adg.c
>
>
> Signed-off-by: Jose Alonso <joalonsof@gmail.com>
> ---
> diff --git a/drivers/s390/cio/qdio.h b/drivers/s390/cio/qdio.h
> index 8acaae1..a563e4c 100644
> --- a/drivers/s390/cio/qdio.h
> +++ b/drivers/s390/cio/qdio.h
> @@ -359,14 +359,12 @@ static inline int multicast_outbound(struct qdio_q *q)
> #define need_siga_sync_out_after_pci(q) \
> (unlikely(q->irq_ptr->siga_flag.sync_out_after_pci))
>
> -#define for_each_input_queue(irq_ptr, q, i) \
> - for (i = 0, q = irq_ptr->input_qs[0]; \
> - i < irq_ptr->nr_input_qs; \
> - q = irq_ptr->input_qs[++i])
> -#define for_each_output_queue(irq_ptr, q, i) \
> - for (i = 0, q = irq_ptr->output_qs[0]; \
> - i < irq_ptr->nr_output_qs; \
> - q = irq_ptr->output_qs[++i])
> +#define for_each_input_queue(irq_ptr, q, i) \
> + for (i = 0; i < irq_ptr->nr_input_qs && \
> + ({ q = irq_ptr->input_qs[i]; 1; }); i++)
> +#define for_each_output_queue(irq_ptr, q, i) \
> + for (i = 0; i < irq_ptr->nr_output_qs && \
> + ({ q = irq_ptr->output_qs[i]; 1; }); i++)

Hi Jose,

I generated a single commit of this part of your patch and applied
it to the s390 git tree.

Thanks!



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