[PATCH 2/2] mm: Drop unneeded ->vm_ops checks

From: Kirill A. Shutemov
Date: Tue Jul 10 2018 - 09:48:43 EST

We now have all VMAs with ->vm_ops set and don't need to check it for
NULL everywhere.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
fs/binfmt_elf.c | 2 +-
fs/kernfs/file.c | 20 +-------------------
fs/proc/task_mmu.c | 2 +-
kernel/events/core.c | 2 +-
kernel/fork.c | 2 +-
mm/hugetlb.c | 2 +-
mm/memory.c | 12 ++++++------
mm/mempolicy.c | 10 +++++-----
mm/mmap.c | 14 +++++++-------
mm/mremap.c | 2 +-
mm/nommu.c | 4 ++--
11 files changed, 27 insertions(+), 45 deletions(-)

diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 0ac456b52bdd..4f171cf21bc2 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1302,7 +1302,7 @@ static bool always_dump_vma(struct vm_area_struct *vma)
* Assume that all vmas with a .name op should always be dumped.
* If this changes, a new vm_ops field can easily be added.
*/
- if (vma->vm_ops && vma->vm_ops->name && vma->vm_ops->name(vma))
+ if (vma->vm_ops->name && vma->vm_ops->name(vma))
return true;

/*
diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c
index 2015d8c45e4a..945c3d306d8f 100644
--- a/fs/kernfs/file.c
+++ b/fs/kernfs/file.c
@@ -336,9 +336,6 @@ static void kernfs_vma_open(struct vm_area_struct *vma)
struct file *file = vma->vm_file;
struct kernfs_open_file *of = kernfs_of(file);

- if (!of->vm_ops)
- return;
-
if (!kernfs_get_active(of->kn))
return;

@@ -354,9 +351,6 @@ static vm_fault_t kernfs_vma_fault(struct vm_fault *vmf)
struct kernfs_open_file *of = kernfs_of(file);
vm_fault_t ret;

- if (!of->vm_ops)
- return VM_FAULT_SIGBUS;
-
if (!kernfs_get_active(of->kn))
return VM_FAULT_SIGBUS;

@@ -374,9 +368,6 @@ static vm_fault_t kernfs_vma_page_mkwrite(struct vm_fault *vmf)
struct kernfs_open_file *of = kernfs_of(file);
vm_fault_t ret;

- if (!of->vm_ops)
- return VM_FAULT_SIGBUS;
-
if (!kernfs_get_active(of->kn))
return VM_FAULT_SIGBUS;

@@ -397,9 +388,6 @@ static int kernfs_vma_access(struct vm_area_struct *vma, unsigned long addr,
struct kernfs_open_file *of = kernfs_of(file);
int ret;

- if (!of->vm_ops)
- return -EINVAL;
-
if (!kernfs_get_active(of->kn))
return -EINVAL;

@@ -419,9 +407,6 @@ static int kernfs_vma_set_policy(struct vm_area_struct *vma,
struct kernfs_open_file *of = kernfs_of(file);
int ret;

- if (!of->vm_ops)
- return 0;
-
if (!kernfs_get_active(of->kn))
return -EINVAL;

@@ -440,9 +425,6 @@ static struct mempolicy *kernfs_vma_get_policy(struct vm_area_struct *vma,
struct kernfs_open_file *of = kernfs_of(file);
struct mempolicy *pol;

- if (!of->vm_ops)
- return vma->vm_policy;
-
if (!kernfs_get_active(of->kn))
return vma->vm_policy;

@@ -511,7 +493,7 @@ static int kernfs_fop_mmap(struct file *file, struct vm_area_struct *vma)
* So error if someone is trying to use close.
*/
rc = -EINVAL;
- if (vma->vm_ops && vma->vm_ops->close)
+ if (vma->vm_ops->close)
goto out_put;

rc = 0;
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index e9679016271f..e959623123e4 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -326,7 +326,7 @@ show_map_vma(struct seq_file *m, struct vm_area_struct *vma, int is_pid)
goto done;
}

- if (vma->vm_ops && vma->vm_ops->name) {
+ if (vma->vm_ops->name) {
name = vma->vm_ops->name(vma);
if (name)
goto done;
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 8f0434a9951a..2e35401a5c68 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -7269,7 +7269,7 @@ static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)

goto got_name;
} else {
- if (vma->vm_ops && vma->vm_ops->name) {
+ if (vma->vm_ops->name) {
name = (char *) vma->vm_ops->name(vma);
if (name)
goto cpy_name;
diff --git a/kernel/fork.c b/kernel/fork.c
index 9440d61b925c..e5e7a220a124 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -519,7 +519,7 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
if (!(tmp->vm_flags & VM_WIPEONFORK))
retval = copy_page_range(mm, oldmm, mpnt);

- if (tmp->vm_ops && tmp->vm_ops->open)
+ if (tmp->vm_ops->open)
tmp->vm_ops->open(tmp);

if (retval)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 039ddbc574e9..2065acc5a6aa 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -637,7 +637,7 @@ EXPORT_SYMBOL_GPL(linear_hugepage_index);
*/
unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
{
- if (vma->vm_ops && vma->vm_ops->pagesize)
+ if (vma->vm_ops->pagesize)
return vma->vm_ops->pagesize(vma);
return PAGE_SIZE;
}
diff --git a/mm/memory.c b/mm/memory.c
index 7206a634270b..02fbef2bd024 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -768,7 +768,7 @@ static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr,
(void *)addr, vma->vm_flags, vma->anon_vma, mapping, index);
pr_alert("file:%pD fault:%pf mmap:%pf readpage:%pf\n",
vma->vm_file,
- vma->vm_ops ? vma->vm_ops->fault : NULL,
+ vma->vm_ops->fault,
vma->vm_file ? vma->vm_file->f_op->mmap : NULL,
mapping ? mapping->a_ops->readpage : NULL);
dump_stack();
@@ -825,7 +825,7 @@ struct page *_vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
if (IS_ENABLED(CONFIG_ARCH_HAS_PTE_SPECIAL)) {
if (likely(!pte_special(pte)))
goto check_pfn;
- if (vma->vm_ops && vma->vm_ops->find_special_page)
+ if (vma->vm_ops->find_special_page)
return vma->vm_ops->find_special_page(vma, addr);
if (vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP))
return NULL;
@@ -2404,7 +2404,7 @@ static void fault_dirty_shared_page(struct vm_area_struct *vma,
{
struct address_space *mapping;
bool dirtied;
- bool page_mkwrite = vma->vm_ops && vma->vm_ops->page_mkwrite;
+ bool page_mkwrite = vma->vm_ops->page_mkwrite;

dirtied = set_page_dirty(page);
VM_BUG_ON_PAGE(PageAnon(page), page);
@@ -2648,7 +2648,7 @@ static int wp_pfn_shared(struct vm_fault *vmf)
{
struct vm_area_struct *vma = vmf->vma;

- if (vma->vm_ops && vma->vm_ops->pfn_mkwrite) {
+ if (vma->vm_ops->pfn_mkwrite) {
int ret;

pte_unmap_unlock(vmf->pte, vmf->ptl);
@@ -2669,7 +2669,7 @@ static int wp_page_shared(struct vm_fault *vmf)

get_page(vmf->page);

- if (vma->vm_ops && vma->vm_ops->page_mkwrite) {
+ if (vma->vm_ops->page_mkwrite) {
int tmp;

pte_unmap_unlock(vmf->pte, vmf->ptl);
@@ -4439,7 +4439,7 @@ int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
vma = find_vma(mm, addr);
if (!vma || vma->vm_start > addr)
break;
- if (vma->vm_ops && vma->vm_ops->access)
+ if (vma->vm_ops->access)
ret = vma->vm_ops->access(vma, addr, buf,
len, write);
if (ret <= 0)
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 9ac49ef17b4e..f0fcf70bcec7 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -651,13 +651,13 @@ static int vma_replace_policy(struct vm_area_struct *vma,
pr_debug("vma %lx-%lx/%lx vm_ops %p vm_file %p set_policy %p\n",
vma->vm_start, vma->vm_end, vma->vm_pgoff,
vma->vm_ops, vma->vm_file,
- vma->vm_ops ? vma->vm_ops->set_policy : NULL);
+ vma->vm_ops->set_policy);

new = mpol_dup(pol);
if (IS_ERR(new))
return PTR_ERR(new);

- if (vma->vm_ops && vma->vm_ops->set_policy) {
+ if (vma->vm_ops->set_policy) {
err = vma->vm_ops->set_policy(vma, new);
if (err)
goto err_out;
@@ -845,7 +845,7 @@ static long do_get_mempolicy(int *policy, nodemask_t *nmask,
up_read(&mm->mmap_sem);
return -EFAULT;
}
- if (vma->vm_ops && vma->vm_ops->get_policy)
+ if (vma->vm_ops->get_policy)
pol = vma->vm_ops->get_policy(vma, addr);
else
pol = vma->vm_policy;
@@ -1617,7 +1617,7 @@ struct mempolicy *__get_vma_policy(struct vm_area_struct *vma,
struct mempolicy *pol = NULL;

if (vma) {
- if (vma->vm_ops && vma->vm_ops->get_policy) {
+ if (vma->vm_ops->get_policy) {
pol = vma->vm_ops->get_policy(vma, addr);
} else if (vma->vm_policy) {
pol = vma->vm_policy;
@@ -1663,7 +1663,7 @@ bool vma_policy_mof(struct vm_area_struct *vma)
{
struct mempolicy *pol;

- if (vma->vm_ops && vma->vm_ops->get_policy) {
+ if (vma->vm_ops->get_policy) {
bool ret = false;

pol = vma->vm_ops->get_policy(vma, vma->vm_start);
diff --git a/mm/mmap.c b/mm/mmap.c
index 0729ed06b01c..366280686b92 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -180,7 +180,7 @@ static struct vm_area_struct *remove_vma(struct vm_area_struct *vma)
struct vm_area_struct *next = vma->vm_next;

might_sleep();
- if (vma->vm_ops && vma->vm_ops->close)
+ if (vma->vm_ops->close)
vma->vm_ops->close(vma);
if (vma->vm_file)
fput(vma->vm_file);
@@ -1001,7 +1001,7 @@ static inline int is_mergeable_vma(struct vm_area_struct *vma,
return 0;
if (vma->vm_file != file)
return 0;
- if (vma->vm_ops && vma->vm_ops->close)
+ if (vma->vm_ops->close)
return 0;
if (!is_mergeable_vm_userfaultfd_ctx(vma, vm_userfaultfd_ctx))
return 0;
@@ -1641,7 +1641,7 @@ int vma_wants_writenotify(struct vm_area_struct *vma, pgprot_t vm_page_prot)
return 0;

/* The backer wishes to know when pages are first written to? */
- if (vm_ops && (vm_ops->page_mkwrite || vm_ops->pfn_mkwrite))
+ if (vm_ops->page_mkwrite || vm_ops->pfn_mkwrite)
return 1;

/* The open routine did something to the protections that pgprot_modify
@@ -2626,7 +2626,7 @@ int __split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
struct vm_area_struct *new;
int err;

- if (vma->vm_ops && vma->vm_ops->split) {
+ if (vma->vm_ops->split) {
err = vma->vm_ops->split(vma, addr);
if (err)
return err;
@@ -2659,7 +2659,7 @@ int __split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
if (new->vm_file)
get_file(new->vm_file);

- if (new->vm_ops && new->vm_ops->open)
+ if (new->vm_ops->open)
new->vm_ops->open(new);

if (new_below)
@@ -2673,7 +2673,7 @@ int __split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
return 0;

/* Clean everything up if vma_adjust failed. */
- if (new->vm_ops && new->vm_ops->close)
+ if (new->vm_ops->close)
new->vm_ops->close(new);
if (new->vm_file)
fput(new->vm_file);
@@ -3234,7 +3234,7 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
goto out_free_mempol;
if (new_vma->vm_file)
get_file(new_vma->vm_file);
- if (new_vma->vm_ops && new_vma->vm_ops->open)
+ if (new_vma->vm_ops->open)
new_vma->vm_ops->open(new_vma);
vma_link(mm, new_vma, prev, rb_link, rb_parent);
*need_rmap_locks = false;
diff --git a/mm/mremap.c b/mm/mremap.c
index 5c2e18505f75..7ab222c283de 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -302,7 +302,7 @@ static unsigned long move_vma(struct vm_area_struct *vma,
need_rmap_locks);
if (moved_len < old_len) {
err = -ENOMEM;
- } else if (vma->vm_ops && vma->vm_ops->mremap) {
+ } else if (vma->vm_ops->mremap) {
err = vma->vm_ops->mremap(new_vma);
}

diff --git a/mm/nommu.c b/mm/nommu.c
index 4452d8bd9ae4..e7f447bfd704 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -764,7 +764,7 @@ static void delete_vma_from_mm(struct vm_area_struct *vma)
*/
static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma)
{
- if (vma->vm_ops && vma->vm_ops->close)
+ if (vma->vm_ops->close)
vma->vm_ops->close(vma);
if (vma->vm_file)
fput(vma->vm_file);
@@ -1489,7 +1489,7 @@ int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
region->vm_pgoff = new->vm_pgoff += npages;
}

- if (new->vm_ops && new->vm_ops->open)
+ if (new->vm_ops->open)
new->vm_ops->open(new);

delete_vma_from_mm(vma);
--
2.18.0