---

yaml
---
r: 130701
b: refs/heads/master
c: fb8ec18
h: refs/heads/master
i:
  130699: 2e42b8f
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 3fff0179e33cd7d0a688dab65700c46ad089e934
+refs/heads/master: fb8ec18c316d869271137c97320dbfd2def56569

trunk/block/blk-core.c

@@ -69,7 +69,7 @@ static void drive_stat_acct(struct request *rq, int new_io)
 	int rw = rq_data_dir(rq);
 	int cpu;
 
-	if (!blk_fs_request(rq) || !disk || !blk_queue_io_stat(disk->queue))
+	if (!blk_fs_request(rq) || !disk || !blk_do_io_stat(disk->queue))
 		return;
 
 	cpu = part_stat_lock();
@@ -1667,7 +1667,7 @@ static void blk_account_io_completion(struct request *req, unsigned int bytes)
 {
 	struct gendisk *disk = req->rq_disk;
 
-	if (!disk || !blk_queue_io_stat(disk->queue))
+	if (!disk || !blk_do_io_stat(disk->queue))
 		return;
 
 	if (blk_fs_request(req)) {
@@ -1686,7 +1686,7 @@ static void blk_account_io_done(struct request *req)
 {
 	struct gendisk *disk = req->rq_disk;
 
-	if (!disk || !blk_queue_io_stat(disk->queue))
+	if (!disk || !blk_do_io_stat(disk->queue))
 		return;
 
 	/*

trunk/block/blk.h

@@ -108,4 +108,12 @@ static inline int blk_cpu_to_group(int cpu)
 #endif
 }
 
+static inline int blk_do_io_stat(struct request_queue *q)
+{
+	if (q)
+		return blk_queue_io_stat(q);
+
+	return 0;
+}
+
 #endif

trunk/drivers/virtio/virtio_pci.c

@@ -192,7 +192,7 @@ static irqreturn_t vp_interrupt(int irq, void *opaque)
 		drv = container_of(vp_dev->vdev.dev.driver,
 				   struct virtio_driver, driver);
 
-		if (drv && drv->config_changed)
+		if (drv->config_changed)
 			drv->config_changed(&vp_dev->vdev);
 	}
 

trunk/include/linux/module.h

@@ -219,6 +219,11 @@ void *__symbol_get_gpl(const char *symbol);
 
 #endif
 
+struct module_ref
+{
+	local_t count;
+} ____cacheline_aligned;
+
 enum module_state
 {
 	MODULE_STATE_LIVE,
@@ -339,11 +344,8 @@ struct module
 	/* Destruction function. */
 	void (*exit)(void);
 
-#ifdef CONFIG_SMP
-	char *refptr;
-#else
-	local_t ref;
-#endif
+	/* Reference counts */
+	struct module_ref ref[NR_CPUS];
 #endif
 };
 #ifndef MODULE_ARCH_INIT
@@ -393,22 +395,13 @@ void __symbol_put(const char *symbol);
 #define symbol_put(x) __symbol_put(MODULE_SYMBOL_PREFIX #x)
 void symbol_put_addr(void *addr);
 
-static inline local_t *__module_ref_addr(struct module *mod, int cpu)
-{
-#ifdef CONFIG_SMP
-	return (local_t *) (mod->refptr + per_cpu_offset(cpu));
-#else
-	return &mod->ref;
-#endif
-}
-
 /* Sometimes we know we already have a refcount, and it's easier not
    to handle the error case (which only happens with rmmod --wait). */
 static inline void __module_get(struct module *module)
 {
 	if (module) {
 		BUG_ON(module_refcount(module) == 0);
-		local_inc(__module_ref_addr(module, get_cpu()));
+		local_inc(&module->ref[get_cpu()].count);
 		put_cpu();
 	}
 }
@@ -420,7 +413,7 @@ static inline int try_module_get(struct module *module)
 	if (module) {
 		unsigned int cpu = get_cpu();
 		if (likely(module_is_live(module)))
-			local_inc(__module_ref_addr(module, cpu));
+			local_inc(&module->ref[cpu].count);
 		else
 			ret = 0;
 		put_cpu();

trunk/kernel/module.c

@@ -573,13 +573,13 @@ static char last_unloaded_module[MODULE_NAME_LEN+1];
 /* Init the unload section of the module. */
 static void module_unload_init(struct module *mod)
 {
-	int cpu;
+	unsigned int i;
 
 	INIT_LIST_HEAD(&mod->modules_which_use_me);
-	for_each_possible_cpu(cpu)
-		local_set(__module_ref_addr(mod, cpu), 0);
+	for (i = 0; i < NR_CPUS; i++)
+		local_set(&mod->ref[i].count, 0);
 	/* Hold reference count during initialization. */
-	local_set(__module_ref_addr(mod, raw_smp_processor_id()), 1);
+	local_set(&mod->ref[raw_smp_processor_id()].count, 1);
 	/* Backwards compatibility macros put refcount during init. */
 	mod->waiter = current;
 }
@@ -717,11 +717,10 @@ static int try_stop_module(struct module *mod, int flags, int *forced)
 
 unsigned int module_refcount(struct module *mod)
 {
-	unsigned int total = 0;
-	int cpu;
+	unsigned int i, total = 0;
 
-	for_each_possible_cpu(cpu)
-		total += local_read(__module_ref_addr(mod, cpu));
+	for (i = 0; i < NR_CPUS; i++)
+		total += local_read(&mod->ref[i].count);
 	return total;
 }
 EXPORT_SYMBOL(module_refcount);
@@ -895,7 +894,7 @@ void module_put(struct module *module)
 {
 	if (module) {
 		unsigned int cpu = get_cpu();
-		local_dec(__module_ref_addr(module, cpu));
+		local_dec(&module->ref[cpu].count);
 		/* Maybe they're waiting for us to drop reference? */
 		if (unlikely(!module_is_live(module)))
 			wake_up_process(module->waiter);
@@ -1465,10 +1464,7 @@ static void free_module(struct module *mod)
 	kfree(mod->args);
 	if (mod->percpu)
 		percpu_modfree(mod->percpu);
-#if defined(CONFIG_MODULE_UNLOAD) && defined(CONFIG_SMP)
-	if (mod->refptr)
-		percpu_modfree(mod->refptr);
-#endif
+
 	/* Free lock-classes: */
 	lockdep_free_key_range(mod->module_core, mod->core_size);
 
@@ -2015,22 +2011,14 @@ static noinline struct module *load_module(void __user *umod,
 	if (err < 0)
 		goto free_mod;
 
-#if defined(CONFIG_MODULE_UNLOAD) && defined(CONFIG_SMP)
-	mod->refptr = percpu_modalloc(sizeof(local_t), __alignof__(local_t),
-				      mod->name);
-	if (!mod->refptr) {
-		err = -ENOMEM;
-		goto free_mod;
-	}
-#endif
 	if (pcpuindex) {
 		/* We have a special allocation for this section. */
 		percpu = percpu_modalloc(sechdrs[pcpuindex].sh_size,
 					 sechdrs[pcpuindex].sh_addralign,
 					 mod->name);
 		if (!percpu) {
 			err = -ENOMEM;
-			goto free_percpu;
+			goto free_mod;
 		}
 		sechdrs[pcpuindex].sh_flags &= ~(unsigned long)SHF_ALLOC;
 		mod->percpu = percpu;
@@ -2294,9 +2282,6 @@ static noinline struct module *load_module(void __user *umod,
  free_percpu:
 	if (percpu)
 		percpu_modfree(percpu);
-#if defined(CONFIG_MODULE_UNLOAD) && defined(CONFIG_SMP)
-	percpu_modfree(mod->refptr);
-#endif
  free_mod:
 	kfree(args);
  free_hdr:

trunk/mm/mlock.c

@@ -294,10 +294,14 @@ static inline int __mlock_posix_error_return(long retval)
  *
  * return number of pages [> 0] to be removed from locked_vm on success
  * of "special" vmas.
+ *
+ * return negative error if vma spanning @start-@range disappears while
+ * mmap semaphore is dropped.  Unlikely?
  */
 long mlock_vma_pages_range(struct vm_area_struct *vma,
 			unsigned long start, unsigned long end)
 {
+	struct mm_struct *mm = vma->vm_mm;
 	int nr_pages = (end - start) / PAGE_SIZE;
 	BUG_ON(!(vma->vm_flags & VM_LOCKED));
 
@@ -310,8 +314,20 @@ long mlock_vma_pages_range(struct vm_area_struct *vma,
 	if (!((vma->vm_flags & (VM_DONTEXPAND | VM_RESERVED)) ||
 			is_vm_hugetlb_page(vma) ||
 			vma == get_gate_vma(current))) {
+		long error;
+		downgrade_write(&mm->mmap_sem);
+
+		error = __mlock_vma_pages_range(vma, start, end, 1);
 
-		return __mlock_vma_pages_range(vma, start, end, 1);
+		up_read(&mm->mmap_sem);
+		/* vma can change or disappear */
+		down_write(&mm->mmap_sem);
+		vma = find_vma(mm, start);
+		/* non-NULL vma must contain @start, but need to check @end */
+		if (!vma ||  end > vma->vm_end)
+			return -ENOMEM;
+
+		return 0;	/* hide other errors from mmap(), et al */
 	}
 
 	/*
@@ -422,14 +438,41 @@ static int mlock_fixup(struct vm_area_struct *vma, struct vm_area_struct **prev,
 	vma->vm_flags = newflags;
 
 	if (lock) {
+		/*
+		 * mmap_sem is currently held for write.  Downgrade the write
+		 * lock to a read lock so that other faults, mmap scans, ...
+		 * while we fault in all pages.
+		 */
+		downgrade_write(&mm->mmap_sem);
+
 		ret = __mlock_vma_pages_range(vma, start, end, 1);
 
-		if (ret > 0) {
+		/*
+		 * Need to reacquire mmap sem in write mode, as our callers
+		 * expect this.  We have no support for atomically upgrading
+		 * a sem to write, so we need to check for ranges while sem
+		 * is unlocked.
+		 */
+		up_read(&mm->mmap_sem);
+		/* vma can change or disappear */
+		down_write(&mm->mmap_sem);
+		*prev = find_vma(mm, start);
+		/* non-NULL *prev must contain @start, but need to check @end */
+		if (!(*prev) || end > (*prev)->vm_end)
+			ret = -ENOMEM;
+		else if (ret > 0) {
 			mm->locked_vm -= ret;
 			ret = 0;
 		} else
 			ret = __mlock_posix_error_return(ret); /* translate if needed */
 	} else {
+		/*
+		 * TODO:  for unlocking, pages will already be resident, so
+		 * we don't need to wait for allocations/reclaim/pagein, ...
+		 * However, unlocking a very large region can still take a
+		 * while.  Should we downgrade the semaphore for both lock
+		 * AND unlock ?
+		 */
 		__mlock_vma_pages_range(vma, start, end, 0);
 	}