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x86: xen: remove the use of VLAIS

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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>
This commit is contained in:
Nick Desaulniers 2018-01-06 13:39:48 -08:00 committed by Boris Ostrovsky
parent 0dd6d272d3
commit 66a640e782
1 changed files with 3 additions and 5 deletions
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8
arch/x86/xen/mmu_pv.c
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@ -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);