mm: add new mmgrab() helper

Apart from adding the helper function itself, the rest of the kernel is
converted mechanically using:

  git grep -l 'atomic_inc.*mm_count' | xargs sed -i 's/atomic_inc(&\(.*\)->mm_count);/mmgrab\(\1\);/'
  git grep -l 'atomic_inc.*mm_count' | xargs sed -i 's/atomic_inc(&\(.*\)\.mm_count);/mmgrab\(\&\1\);/'

This is needed for a later patch that hooks into the helper, but might
be a worthwhile cleanup on its own.

(Michal Hocko provided most of the kerneldoc comment.)

Link: http://lkml.kernel.org/r/20161218123229.22952-1-vegard.nossum@oracle.com
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

25 files changed, 26 insertions, 26 deletions

diff --git a/arch/alpha/kernel/smp.c b/arch/alpha/kernel/smp.c
index 46bf263c3153..acb4b146a607 100644
--- a/arch/alpha/kernel/smp.c
+++ b/arch/alpha/kernel/smp.c
@@ -144,7 +144,7 @@ smp_callin(void)
 		alpha_mv.smp_callin();
 
 	/* All kernel threads share the same mm context.  */
-	atomic_inc(&init_mm.mm_count);
+	mmgrab(&init_mm);
 	current->active_mm = &init_mm;
 
 	/* inform the notifiers about the new cpu */
diff --git a/arch/arc/kernel/smp.c b/arch/arc/kernel/smp.c
index 2afbafadb6ab..695624181682 100644
--- a/arch/arc/kernel/smp.c
+++ b/arch/arc/kernel/smp.c
@@ -140,7 +140,7 @@ void start_kernel_secondary(void)
 	setup_processor();
 
 	atomic_inc(&mm->mm_users);
-	atomic_inc(&mm->mm_count);
+	mmgrab(mm);
 	current->active_mm = mm;
 	cpumask_set_cpu(cpu, mm_cpumask(mm));
 
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 7dd14e8395e6..c6514ce0fcbc 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -371,7 +371,7 @@ asmlinkage void secondary_start_kernel(void)
 	 * reference and switch to it.
 	 */
 	cpu = smp_processor_id();
-	atomic_inc(&mm->mm_count);
+	mmgrab(mm);
 	current->active_mm = mm;
 	cpumask_set_cpu(cpu, mm_cpumask(mm));
 
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index a8ec5da530af..827d52d78b67 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -222,7 +222,7 @@ asmlinkage void secondary_start_kernel(void)
 	 * All kernel threads share the same mm context; grab a
 	 * reference and switch to it.
 	 */
-	atomic_inc(&mm->mm_count);
+	mmgrab(mm);
 	current->active_mm = mm;
 
 	/*
diff --git a/arch/blackfin/mach-common/smp.c b/arch/blackfin/mach-common/smp.c
index 23c4ef5f8bdc..bc5617ef7128 100644
--- a/arch/blackfin/mach-common/smp.c
+++ b/arch/blackfin/mach-common/smp.c
@@ -308,7 +308,7 @@ void secondary_start_kernel(void)
 
 	/* Attach the new idle task to the global mm. */
 	atomic_inc(&mm->mm_users);
-	atomic_inc(&mm->mm_count);
+	mmgrab(mm);
 	current->active_mm = mm;
 
 	preempt_disable();
diff --git a/arch/hexagon/kernel/smp.c b/arch/hexagon/kernel/smp.c
index 983bae7d2665..c02a6455839e 100644
--- a/arch/hexagon/kernel/smp.c
+++ b/arch/hexagon/kernel/smp.c
@@ -162,7 +162,7 @@ void start_secondary(void)
 	);
 
 	/*  Set the memory struct  */
-	atomic_inc(&init_mm.mm_count);
+	mmgrab(&init_mm);
 	current->active_mm = &init_mm;
 
 	cpu = smp_processor_id();
diff --git a/arch/ia64/kernel/setup.c b/arch/ia64/kernel/setup.c
index c483ece3eb84..d68322966f33 100644
--- a/arch/ia64/kernel/setup.c
+++ b/arch/ia64/kernel/setup.c
@@ -994,7 +994,7 @@ cpu_init (void)
 	 */
 	ia64_setreg(_IA64_REG_CR_DCR,  (  IA64_DCR_DP | IA64_DCR_DK | IA64_DCR_DX | IA64_DCR_DR
 					| IA64_DCR_DA | IA64_DCR_DD | IA64_DCR_LC));
-	atomic_inc(&init_mm.mm_count);
+	mmgrab(&init_mm);
 	current->active_mm = &init_mm;
 	BUG_ON(current->mm);
 
diff --git a/arch/m32r/kernel/setup.c b/arch/m32r/kernel/setup.c
index 136c69f1fb8a..b18bc0bd6544 100644
--- a/arch/m32r/kernel/setup.c
+++ b/arch/m32r/kernel/setup.c
@@ -403,7 +403,7 @@ void __init cpu_init (void)
 	printk(KERN_INFO "Initializing CPU#%d\n", cpu_id);
 
 	/* Set up and load the per-CPU TSS and LDT */
-	atomic_inc(&init_mm.mm_count);
+	mmgrab(&init_mm);
 	current->active_mm = &init_mm;
 	if (current->mm)
 		BUG();
diff --git a/arch/metag/kernel/smp.c b/arch/metag/kernel/smp.c
index bad13232de51..af9cff547a19 100644
--- a/arch/metag/kernel/smp.c
+++ b/arch/metag/kernel/smp.c
@@ -345,7 +345,7 @@ asmlinkage void secondary_start_kernel(void)
 	 * reference and switch to it.
 	 */
 	atomic_inc(&mm->mm_users);
-	atomic_inc(&mm->mm_count);
+	mmgrab(mm);
 	current->active_mm = mm;
 	cpumask_set_cpu(cpu, mm_cpumask(mm));
 	enter_lazy_tlb(mm, current);
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index cb479be31a50..49c6df20672a 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -2232,7 +2232,7 @@ void per_cpu_trap_init(bool is_boot_cpu)
 	if (!cpu_data[cpu].asid_cache)
 		cpu_data[cpu].asid_cache = asid_first_version(cpu);
 
-	atomic_inc(&init_mm.mm_count);
+	mmgrab(&init_mm);
 	current->active_mm = &init_mm;
 	BUG_ON(current->mm);
 	enter_lazy_tlb(&init_mm, current);
diff --git a/arch/mn10300/kernel/smp.c b/arch/mn10300/kernel/smp.c
index 426173c4b0b9..e65b5cc2fa67 100644
--- a/arch/mn10300/kernel/smp.c
+++ b/arch/mn10300/kernel/smp.c
@@ -589,7 +589,7 @@ static void __init smp_cpu_init(void)
 	}
 	printk(KERN_INFO "Initializing CPU#%d\n", cpu_id);
 
-	atomic_inc(&init_mm.mm_count);
+	mmgrab(&init_mm);
 	current->active_mm = &init_mm;
 	BUG_ON(current->mm);
 
diff --git a/arch/parisc/kernel/smp.c b/arch/parisc/kernel/smp.c
index 75dab2871346..67b452b41ff6 100644
--- a/arch/parisc/kernel/smp.c
+++ b/arch/parisc/kernel/smp.c
@@ -279,7 +279,7 @@ smp_cpu_init(int cpunum)
 	set_cpu_online(cpunum, true);
 
 	/* Initialise the idle task for this CPU */
-	atomic_inc(&init_mm.mm_count);
+	mmgrab(&init_mm);
 	current->active_mm = &init_mm;
 	BUG_ON(current->mm);
 	enter_lazy_tlb(&init_mm, current);
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 893bd7f79be6..573fb3a461b5 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -707,7 +707,7 @@ void start_secondary(void *unused)
 	unsigned int cpu = smp_processor_id();
 	int i, base;
 
-	atomic_inc(&init_mm.mm_count);
+	mmgrab(&init_mm);
 	current->active_mm = &init_mm;
 
 	smp_store_cpu_info(cpu);
diff --git a/arch/s390/kernel/processor.c b/arch/s390/kernel/processor.c
index 21004aaac69b..bc2b60dcb178 100644
--- a/arch/s390/kernel/processor.c
+++ b/arch/s390/kernel/processor.c
@@ -73,7 +73,7 @@ void cpu_init(void)
 	get_cpu_id(id);
 	if (machine_has_cpu_mhz)
 		update_cpu_mhz(NULL);
-	atomic_inc(&init_mm.mm_count);
+	mmgrab(&init_mm);
 	current->active_mm = &init_mm;
 	BUG_ON(current->mm);
 	enter_lazy_tlb(&init_mm, current);
diff --git a/arch/score/kernel/traps.c b/arch/score/kernel/traps.c
index 2b22bcf02c27..569ac02f68df 100644
--- a/arch/score/kernel/traps.c
+++ b/arch/score/kernel/traps.c
@@ -336,7 +336,7 @@ void __init trap_init(void)
 	set_except_vector(18, handle_dbe);
 	flush_icache_range(DEBUG_VECTOR_BASE_ADDR, IRQ_VECTOR_BASE_ADDR);
 
-	atomic_inc(&init_mm.mm_count);
+	mmgrab(&init_mm);
 	current->active_mm = &init_mm;
 	cpu_cache_init();
 }
diff --git a/arch/sh/kernel/smp.c b/arch/sh/kernel/smp.c
index 38e7860845db..ee379c699c08 100644
--- a/arch/sh/kernel/smp.c
+++ b/arch/sh/kernel/smp.c
@@ -178,7 +178,7 @@ asmlinkage void start_secondary(void)
 	struct mm_struct *mm = &init_mm;
 
 	enable_mmu();
-	atomic_inc(&mm->mm_count);
+	mmgrab(mm);
 	atomic_inc(&mm->mm_users);
 	current->active_mm = mm;
 #ifdef CONFIG_MMU
diff --git a/arch/sparc/kernel/leon_smp.c b/arch/sparc/kernel/leon_smp.c
index 71e16f2241c2..b99d33797e1d 100644
--- a/arch/sparc/kernel/leon_smp.c
+++ b/arch/sparc/kernel/leon_smp.c
@@ -93,7 +93,7 @@ void leon_cpu_pre_online(void *arg)
 			     : "memory" /* paranoid */);
 
 	/* Attach to the address space of init_task. */
-	atomic_inc(&init_mm.mm_count);
+	mmgrab(&init_mm);
 	current->active_mm = &init_mm;
 
 	while (!cpumask_test_cpu(cpuid, &smp_commenced_mask))
diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c
index 90a02cb64e20..8e3e13924594 100644
--- a/arch/sparc/kernel/smp_64.c
+++ b/arch/sparc/kernel/smp_64.c
@@ -122,7 +122,7 @@ void smp_callin(void)
 	current_thread_info()->new_child = 0;
 
 	/* Attach to the address space of init_task. */
-	atomic_inc(&init_mm.mm_count);
+	mmgrab(&init_mm);
 	current->active_mm = &init_mm;
 
 	/* inform the notifiers about the new cpu */
diff --git a/arch/sparc/kernel/sun4d_smp.c b/arch/sparc/kernel/sun4d_smp.c
index 9d98e5002a09..7b55c50eabe5 100644
--- a/arch/sparc/kernel/sun4d_smp.c
+++ b/arch/sparc/kernel/sun4d_smp.c
@@ -93,7 +93,7 @@ void sun4d_cpu_pre_online(void *arg)
 	show_leds(cpuid);
 
 	/* Attach to the address space of init_task. */
-	atomic_inc(&init_mm.mm_count);
+	mmgrab(&init_mm);
 	current->active_mm = &init_mm;
 
 	local_ops->cache_all();
diff --git a/arch/sparc/kernel/sun4m_smp.c b/arch/sparc/kernel/sun4m_smp.c
index 278c40abce82..633c4cf6fdb0 100644
--- a/arch/sparc/kernel/sun4m_smp.c
+++ b/arch/sparc/kernel/sun4m_smp.c
@@ -59,7 +59,7 @@ void sun4m_cpu_pre_online(void *arg)
 			     : "memory" /* paranoid */);
 
 	/* Attach to the address space of init_task. */
-	atomic_inc(&init_mm.mm_count);
+	mmgrab(&init_mm);
 	current->active_mm = &init_mm;
 
 	while (!cpumask_test_cpu(cpuid, &smp_commenced_mask))
diff --git a/arch/sparc/kernel/traps_32.c b/arch/sparc/kernel/traps_32.c
index 4f21df7d4f13..ecddac5a4c96 100644
--- a/arch/sparc/kernel/traps_32.c
+++ b/arch/sparc/kernel/traps_32.c
@@ -448,7 +448,7 @@ void trap_init(void)
 		thread_info_offsets_are_bolixed_pete();
 
 	/* Attach to the address space of init_task. */
-	atomic_inc(&init_mm.mm_count);
+	mmgrab(&init_mm);
 	current->active_mm = &init_mm;
 
 	/* NOTE: Other cpus have this done as they are started
diff --git a/arch/sparc/kernel/traps_64.c b/arch/sparc/kernel/traps_64.c
index dfc97a47c9a0..e022d7b00390 100644
--- a/arch/sparc/kernel/traps_64.c
+++ b/arch/sparc/kernel/traps_64.c
@@ -2837,6 +2837,6 @@ void __init trap_init(void)
 	/* Attach to the address space of init_task.  On SMP we
 	 * do this in smp.c:smp_callin for other cpus.
 	 */
-	atomic_inc(&init_mm.mm_count);
+	mmgrab(&init_mm);
 	current->active_mm = &init_mm;
 }
diff --git a/arch/tile/kernel/smpboot.c b/arch/tile/kernel/smpboot.c
index 6c0abaacec33..53ce940a5016 100644
--- a/arch/tile/kernel/smpboot.c
+++ b/arch/tile/kernel/smpboot.c
@@ -160,7 +160,7 @@ static void start_secondary(void)
 	__this_cpu_write(current_asid, min_asid);
 
 	/* Set up this thread as another owner of the init_mm */
-	atomic_inc(&init_mm.mm_count);
+	mmgrab(&init_mm);
 	current->active_mm = &init_mm;
 	if (current->mm)
 		BUG();
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index f07005e6f461..c64ca5929cb5 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1510,7 +1510,7 @@ void cpu_init(void)
 	for (i = 0; i <= IO_BITMAP_LONGS; i++)
 		t->io_bitmap[i] = ~0UL;
 
-	atomic_inc(&init_mm.mm_count);
+	mmgrab(&init_mm);
 	me->active_mm = &init_mm;
 	BUG_ON(me->mm);
 	enter_lazy_tlb(&init_mm, me);
@@ -1561,7 +1561,7 @@ void cpu_init(void)
 	/*
 	 * Set up and load the per-CPU TSS and LDT
 	 */
-	atomic_inc(&init_mm.mm_count);
+	mmgrab(&init_mm);
 	curr->active_mm = &init_mm;
 	BUG_ON(curr->mm);
 	enter_lazy_tlb(&init_mm, curr);
diff --git a/arch/xtensa/kernel/smp.c b/arch/xtensa/kernel/smp.c
index fc4ad21a5ed4..9bf5cea3bae4 100644
--- a/arch/xtensa/kernel/smp.c
+++ b/arch/xtensa/kernel/smp.c
@@ -136,7 +136,7 @@ void secondary_start_kernel(void)
 	/* All kernel threads share the same mm context. */
 
 	atomic_inc(&mm->mm_users);
-	atomic_inc(&mm->mm_count);
+	mmgrab(mm);
 	current->active_mm = mm;
 	cpumask_set_cpu(cpu, mm_cpumask(mm));
 	enter_lazy_tlb(mm, current);