Re: [PATCH v2 04/20] x86, ACPI: Increase override tables number limit

Tejun Heo
2013-04-04T17:50:26Z

On Sat, Mar 09, 2013 at 10:44:31PM -0800, Yinghai Lu wrote:
> Current acpi tables in initrd is limited to 10, that is too small.
> 64 should be good enough as we have 35 sigs and could have several
> SSDT.
>
> Two problems in current code prevent us from increasing limit:
> 1. that cpio file info array is put in stack, as every element is 32
> bytes, could run out of stack if we have that array size to 64.
> We can move it out from stack, and make it as global and put it in
> __initdata section.
> 2. early_ioremap only can remap 256k one time. Current code is mapping
> 10 tables one time. If we increase that limit, whole size could be
> more than 256k, early_ioremap will fail with that.
> We can map table one by one during copying, instead of mapping
> all them one time.
>
> -v2: According to tj, split it out to separated patch, also
> rename array name to acpi_initrd_files.
>
> Signed-off-by: Yinghai <yinghai@kernel.org>
> Cc: Rafael J. Wysocki <rjw@sisk.pl>
> Cc: linux-acpi@vger.kernel.org

Acked-by: Tejun Heo <tj@kernel.org>

> @@ -648,14 +647,14 @@ void __init acpi_initrd_override(void *data, size_t size)
> memblock_reserve(acpi_tables_addr, acpi_tables_addr + all_tables_size);
> arch_reserve_mem_area(acpi_tables_addr, all_tables_size);
>
> - p = early_ioremap(acpi_tables_addr, all_tables_size);
> -

It'd be nice to have a brief comment here explaining why we're mapping
each table separately.

> for (no = 0; no < table_nr; no++) {
> - memcpy(p + total_offset, early_initrd_files[no].data,
> - early_initrd_files[no].size);
> - total_offset += early_initrd_files[no].size;
> + phys_addr_t size = acpi_initrd_files[no].size;
> +
> + p = early_ioremap(acpi_tables_addr + total_offset, size);
> + memcpy(p, acpi_initrd_files[no].data, size);
> + early_iounmap(p, size);
> + total_offset += size;
> }
> - early_iounmap(p, all_tables_size);

Thanks.

--
tejun