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Commit 66a640e7 authored by Nick Desaulniers's avatar Nick Desaulniers Committed by Boris Ostrovsky
Browse files

x86: xen: remove the use of VLAIS 

Variable Length Arrays In Structs (VLAIS) is not supported by Clang, and
frowned upon by others.

https://lkml.org/lkml/2013/9/23/500



Here, the VLAIS was used because the size of the bitmap returned from
xen_mc_entry() depended on possibly (based on kernel configuration)
runtime sized data. Rather than declaring args as a VLAIS then calling
sizeof on *args, we calculate the appropriate sizeof args manually.
Further, we can get rid of the #ifdef's and rely on num_possible_cpus()
(thanks to a helpful checkpatch warning from an earlier version of this
patch).

Suggested-by: default avatarJuergen Gross <jgross@suse.com>
Signed-off-by: default avatarNick Desaulniers <nick.desaulniers@gmail.com>
Reviewed-by: default avatarJuergen Gross <jgross@suse.com>
Signed-off-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
parent 0dd6d272

arch/x86/xen/mmu_pv.c

+3 −5
Original line number Diff line number Diff line
@@ -1339,20 +1339,18 @@ static void xen_flush_tlb_others(const struct cpumask *cpus, 
{

	struct {

		struct mmuext_op op;

#ifdef CONFIG_SMP

		DECLARE_BITMAP(mask, num_processors);

#else

		DECLARE_BITMAP(mask, NR_CPUS);

#endif

	} *args;

	struct multicall_space mcs;

	const size_t mc_entry_size = sizeof(args->op) +

		sizeof(args->mask[0]) * BITS_TO_LONGS(num_possible_cpus());



	trace_xen_mmu_flush_tlb_others(cpus, info->mm, info->start, info->end);



	if (cpumask_empty(cpus))

		return;		/* nothing to do */



	mcs = xen_mc_entry(sizeof(*args));

	mcs = xen_mc_entry(mc_entry_size);

	args = mcs.args;

	args->op.arg2.vcpumask = to_cpumask(args->mask);