Commit 66a640e7 authored Jan 06, 2018 by Nick Desaulniers Committed by Boris Ostrovsky Jan 08, 2018

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: Juergen Gross <jgross@suse.com>
Signed-off-by: Nick Desaulniers <nick.desaulniers@gmail.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Boris 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);

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