Quoting r. Roland Dreier <[EMAIL PROTECTED]>:
> Subject: Re: [PATCH updated] mthca: fix page shift calculation
>
> Michael> Fix page shift calculation: for all pages except possibly
> Michael> the last one, the byte beyond the buffer end must be page
> Michael> aligned.
>
> Good catch. But it seems to me that we don't have to worry about the
> first page either, because of the trick
>
> buffer_list[0].size += buffer_list[0].addr & ((1ULL << shift) - 1);
> buffer_list[0].addr &= ~0ull << shift;
>
> later on.
Hmm.
Lets suppose I have a first chunk in bytes 1 to 2095,
and then another chunk in bytes 0x100000 to 0x1ffffff - should not we
limit the page size to 4K? Does your proposed change do this?
> Does the patch below make sense?
>
> - R.
>
> --- infiniband/hw/mthca/mthca_provider.c (revision 4754)
> +++ infiniband/hw/mthca/mthca_provider.c (working copy)
> @@ -778,17 +778,17 @@ static struct ib_mr *mthca_reg_phys_mr(s
> mask = 0;
> total_size = 0;
> for (i = 0; i < num_phys_buf; ++i) {
> - if (i != 0 && buffer_list[i].addr & ~PAGE_MASK)
> - return ERR_PTR(-EINVAL);
> - if (i != 0 && i != num_phys_buf - 1 &&
> - (buffer_list[i].size & ~PAGE_MASK))
> - return ERR_PTR(-EINVAL);
> + if (i != 0)
> + mask |= buffer_list[i].addr;
> + if (i != 0 && i != num_phys_buf - 1)
> + mask |= buffer_list[i].size;
>
> total_size += buffer_list[i].size;
> - if (i > 0)
> - mask |= buffer_list[i].addr;
> }
>
> + if (mask & ~PAGE_MASK)
> + return ERR_PTR(-EINVAL);
> +
> /* Find largest page shift we can use to cover buffers */
> for (shift = PAGE_SHIFT; shift < 31; ++shift)
> if (num_phys_buf > 1) {
>
--
MST
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