x86: change flush_tlb_others to take a const struct cpumask

Impact: reduce stack usage, use new cpumask API.

This is made a little more tricky by uv_flush_tlb_others which
actually alters its argument, for an IPI to be sent to the remaining
cpus in the mask.

I solve this by allocating a cpumask_var_t for this case and falling back
to IPI should this fail.

To eliminate temporaries in the caller, all flush_tlb_others implementations
now do the this-cpu-elimination step themselves.

Note also the curious "cpus_or(f->flush_cpumask, cpumask, f->flush_cpumask)"
which has been there since pre-git and yet f->flush_cpumask is always zero
at this point.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Mike Travis <travis@sgi.com>

3 files changed, 11 insertions, 8 deletions

diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index ba3e2ff6aedc..c26c6bf4da00 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -244,7 +244,8 @@ struct pv_mmu_ops {
         void (*flush_tlb_user)(void);
         void (*flush_tlb_kernel)(void);
         void (*flush_tlb_single)(unsigned long addr);
-        void (*flush_tlb_others)(const cpumask_t *cpus, struct mm_struct *mm,
+        void (*flush_tlb_others)(const struct cpumask *cpus,
+                                 struct mm_struct *mm,
                                  unsigned long va);
 
         /* Hooks for allocating and freeing a pagetable top-level */
@@ -984,10 +985,11 @@ static inline void __flush_tlb_single(unsigned long addr)
         PVOP_VCALL1(pv_mmu_ops.flush_tlb_single, addr);
 }
 
-static inline void flush_tlb_others(cpumask_t cpumask, struct mm_struct *mm,
+static inline void flush_tlb_others(const struct cpumask *cpumask,
+                                    struct mm_struct *mm,
                                     unsigned long va)
 {
-        PVOP_VCALL3(pv_mmu_ops.flush_tlb_others, &cpumask, mm, va);
+        PVOP_VCALL3(pv_mmu_ops.flush_tlb_others, cpumask, mm, va);
 }
 
 static inline int paravirt_pgd_alloc(struct mm_struct *mm)
diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h
index 0e7bbb549116..f4e1b550ce61 100644
--- a/arch/x86/include/asm/tlbflush.h
+++ b/arch/x86/include/asm/tlbflush.h
@@ -113,7 +113,7 @@ static inline void flush_tlb_range(struct vm_area_struct *vma,
                 __flush_tlb();
 }
 
-static inline void native_flush_tlb_others(const cpumask_t *cpumask,
+static inline void native_flush_tlb_others(const struct cpumask *cpumask,
                                            struct mm_struct *mm,
                                            unsigned long va)
 {
@@ -142,8 +142,8 @@ static inline void flush_tlb_range(struct vm_area_struct *vma,
         flush_tlb_mm(vma->vm_mm);
 }
 
-void native_flush_tlb_others(const cpumask_t *cpumask, struct mm_struct *mm,
-                             unsigned long va);
+void native_flush_tlb_others(const struct cpumask *cpumask,
+                             struct mm_struct *mm, unsigned long va);
 
 #define TLBSTATE_OK     1
 #define TLBSTATE_LAZY   2
@@ -166,7 +166,7 @@ static inline void reset_lazy_tlbstate(void)
 #endif  /* SMP */
 
 #ifndef CONFIG_PARAVIRT
-#define flush_tlb_others(mask, mm, va)  native_flush_tlb_others(&mask, mm, va)
+#define flush_tlb_others(mask, mm, va)  native_flush_tlb_others(mask, mm, va)
 #endif
 
 static inline void flush_tlb_kernel_range(unsigned long start,
diff --git a/arch/x86/include/asm/uv/uv_bau.h b/arch/x86/include/asm/uv/uv_bau.h
index 50423c7b56b2..74e6393bfddb 100644
--- a/arch/x86/include/asm/uv/uv_bau.h
+++ b/arch/x86/include/asm/uv/uv_bau.h
@@ -325,7 +325,8 @@ static inline void bau_cpubits_clear(struct bau_local_cpumask *dstp, int nbits)
 #define cpubit_isset(cpu, bau_local_cpumask) \
         test_bit((cpu), (bau_local_cpumask).bits)
 
-extern int uv_flush_tlb_others(cpumask_t *, struct mm_struct *, unsigned long);
+extern int uv_flush_tlb_others(struct cpumask *,
+                               struct mm_struct *, unsigned long);
 extern void uv_bau_message_intr1(void);
 extern void uv_bau_timeout_intr1(void);