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| author | Jeremy Fitzhardinge <jeremy@goop.org> | 2008-04-02 10:54:10 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-04-24 23:57:33 +0200 |
| commit | 2bd50036b5dfc929390ddc48be7f6314447b2be3 (patch) | |
| tree | 638901ec17236c692273ce18e9160e7d29264a26 /arch/x86/xen | |
| parent | 41e332b2a2dfe514cd441ed0ce1096ed1863e378 (diff) | |
| download | linux-2bd50036b5dfc929390ddc48be7f6314447b2be3.tar.gz linux-2bd50036b5dfc929390ddc48be7f6314447b2be3.tar.bz2 linux-2bd50036b5dfc929390ddc48be7f6314447b2be3.zip | |
xen: allow set_pte_at on init_mm to be lockless
The usual pagetable locking protocol doesn't seem to apply to updates
to init_mm, so don't rely on preemption being disabled in xen_set_pte_at
on init_mm.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/x86/xen')
| -rw-r--r-- | arch/x86/xen/mmu.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c index 272635aaef88..6cbcf65609ad 100644 --- a/arch/x86/xen/mmu.c +++ b/arch/x86/xen/mmu.c @@ -156,6 +156,10 @@ void set_pte_mfn(unsigned long vaddr, unsigned long mfn, pgprot_t flags) void xen_set_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pteval) { + /* updates to init_mm may be done without lock */ + if (mm == &init_mm) + preempt_disable(); + if (mm == current->mm || mm == &init_mm) { if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) { struct multicall_space mcs; @@ -163,12 +167,16 @@ void xen_set_pte_at(struct mm_struct *mm, unsigned long addr, MULTI_update_va_mapping(mcs.mc, addr, pteval, 0); xen_mc_issue(PARAVIRT_LAZY_MMU); - return; + goto out; } else if (HYPERVISOR_update_va_mapping(addr, pteval, 0) == 0) - return; + goto out; } xen_set_pte(ptep, pteval); + +out: + if (mm == &init_mm) + preempt_enable(); } pteval_t xen_pte_val(pte_t pte) |