[PATCH v12 08/31] mm: introduce INIT_VMA()

[Laurent Dufour]

Some VMA struct fields need to be initialized once the VMA structure is
allocated.
Currently this only concerns anon_vma_chain field but some other will be
added to support the speculative page fault.

Instead of spreading the initialization calls all over the code, let's
introduce a dedicated inline function.

Signed-off-by: Laurent Dufour <ldufour@xxxxxxxxxxxxx>
---
 fs/exec.c          | 1 +
 include/linux/mm.h | 5 +++++
 kernel/fork.c      | 2 +-
 mm/mmap.c          | 3 +++
 mm/nommu.c         | 1 +
 5 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/fs/exec.c b/fs/exec.c
index 2e0033348d8e..9762e060295c 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -266,6 +266,7 @@ static int __bprm_mm_init(struct linux_binprm *bprm)
 	vma->vm_start = vma->vm_end - PAGE_SIZE;
 	vma->vm_flags = VM_SOFTDIRTY | VM_STACK_FLAGS | VM_STACK_INCOMPLETE_SETUP;
 	vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
+	INIT_VMA(vma);
 
 	err = insert_vm_struct(mm, vma);
 	if (err)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 4ba2f53f9d60..2ceb1d2869a6 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1407,6 +1407,11 @@ struct zap_details {
 	pgoff_t last_index;			/* Highest page->index to unmap */
 };
 
+static inline void INIT_VMA(struct vm_area_struct *vma)
+{
+	INIT_LIST_HEAD(&vma->anon_vma_chain);
+}
+
 struct page *_vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
 			     pte_t pte, bool with_public_device);
 #define vm_normal_page(vma, addr, pte) _vm_normal_page(vma, addr, pte, false)
diff --git a/kernel/fork.c b/kernel/fork.c
index 915be4918a2b..f8dae021c2e5 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -341,7 +341,7 @@ struct vm_area_struct *vm_area_dup(struct vm_area_struct *orig)
 
 	if (new) {
 		*new = *orig;
-		INIT_LIST_HEAD(&new->anon_vma_chain);
+		INIT_VMA(new);
 	}
 	return new;
 }
diff --git a/mm/mmap.c b/mm/mmap.c
index bd7b9f293b39..5ad3a3228d76 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1765,6 +1765,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
 	vma->vm_flags = vm_flags;
 	vma->vm_page_prot = vm_get_page_prot(vm_flags);
 	vma->vm_pgoff = pgoff;
+	INIT_VMA(vma);
 
 	if (file) {
 		if (vm_flags & VM_DENYWRITE) {
@@ -3037,6 +3038,7 @@ static int do_brk_flags(unsigned long addr, unsigned long len, unsigned long fla
 	}
 
 	vma_set_anonymous(vma);
+	INIT_VMA(vma);
 	vma->vm_start = addr;
 	vma->vm_end = addr + len;
 	vma->vm_pgoff = pgoff;
@@ -3395,6 +3397,7 @@ static struct vm_area_struct *__install_special_mapping(
 	if (unlikely(vma == NULL))
 		return ERR_PTR(-ENOMEM);
 
+	INIT_VMA(vma);
 	vma->vm_start = addr;
 	vma->vm_end = addr + len;
 
diff --git a/mm/nommu.c b/mm/nommu.c
index 749276beb109..acf7ca72ca90 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1210,6 +1210,7 @@ unsigned long do_mmap(struct file *file,
 	region->vm_flags = vm_flags;
 	region->vm_pgoff = pgoff;
 
+	INIT_VMA(vma);
 	vma->vm_flags = vm_flags;
 	vma->vm_pgoff = pgoff;
 
-- 
2.21.0