diff mbox

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

Message ID 20180710134821.84709-3-kirill.shutemov@linux.intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

kirill.shutemov@linux.intel.com July 10, 2018, 1:48 p.m. UTC 
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@linux.intel.com>
---
 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(-)

Comments

Guenter Roeck July 11, 2018, 10:17 p.m. UTC | #1 
Hi,

On Tue, Jul 10, 2018 at 04:48:21PM +0300, Kirill A. Shutemov wrote:
> 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@linux.intel.com>

This patch causes two of my qemu tests to fail:
	arm:mps2-an385:mps2_defconfig:mps2-an385
	xtensa:de212:kc705-nommu:nommu_kc705_defconfig

Both are nommu configurations.

Reverting the patch fixes the problem. Bisect log is attached for reference.

Guenter

---
# bad: [98be45067040799a801e6ce52d8bf4659a153893] Add linux-next specific files for 20180711
# good: [1e4b044d22517cae7047c99038abb444423243ca] Linux 4.18-rc4
git bisect start 'HEAD' 'v4.18-rc4'
# good: [ade30e73739a5174bcaee5860fee76c2365548c5] Merge remote-tracking branch 'crypto/master'
git bisect good ade30e73739a5174bcaee5860fee76c2365548c5
# good: [792be221c35d19a1c486789e5b5c91c05279b94d] Merge remote-tracking branch 'tip/auto-latest'
git bisect good 792be221c35d19a1c486789e5b5c91c05279b94d
# good: [1d66737ba99400ab9a79c906a25b2090f4cc8b18] Merge remote-tracking branch 'mux/for-next'
git bisect good 1d66737ba99400ab9a79c906a25b2090f4cc8b18
# good: [c02d5416bd8504866dd80d2129f4648747166b6f] Merge remote-tracking branch 'kspp/for-next/kspp'
git bisect good c02d5416bd8504866dd80d2129f4648747166b6f
# bad: [1e741337a9416010a48c6034855e316ba8057111] ntb: ntb_hw_switchtec: cleanup 64bit IO defines to use the common header
git bisect bad 1e741337a9416010a48c6034855e316ba8057111
# good: [205a106bac127145a4defae7d0d35945001fe924] kernel/memremap, kasan: make ZONE_DEVICE with work with KASAN
git bisect good 205a106bac127145a4defae7d0d35945001fe924
# good: [e87ebebf76c9ceeaea21a256341d6765c657e550] mm, oom: remove sleep from under oom_lock
git bisect good e87ebebf76c9ceeaea21a256341d6765c657e550
# bad: [1f927d8f894e116af625b2326b355f5292c89d2b] mm/page_owner: align with pageblock_nr pages
git bisect bad 1f927d8f894e116af625b2326b355f5292c89d2b
# bad: [cc8ce33f3475478af93a876e0cf4a99eabbe49e9] mm: revert mem_cgroup_put() introduction
git bisect bad cc8ce33f3475478af93a876e0cf4a99eabbe49e9
# bad: [1f989b6a333fc8d6bddd1552420bb97e3295468a] list_lru-prefetch-neighboring-list-entries-before-acquiring-lock-fix
git bisect bad 1f989b6a333fc8d6bddd1552420bb97e3295468a
# bad: [0454d28f4858b6c8b2606417d35e4e6868699130] mm, swap: fix race between swapoff and some swap operations
git bisect bad 0454d28f4858b6c8b2606417d35e4e6868699130
# bad: [7efeddad4bc281bf61f411a7fe9b19f3689cf62f] mm, swap: fix race between swapoff and some swap operations
git bisect bad 7efeddad4bc281bf61f411a7fe9b19f3689cf62f
# bad: [4a110365f1da9d5cabbd0a01796027c0a6d5e80b] mm: drop unneeded ->vm_ops checks
git bisect bad 4a110365f1da9d5cabbd0a01796027c0a6d5e80b
# first bad commit: [4a110365f1da9d5cabbd0a01796027c0a6d5e80b] mm: drop unneeded ->vm_ops checks
Andrew Morton July 11, 2018, 10:40 p.m. UTC | #2 
On Wed, 11 Jul 2018 15:17:42 -0700 Guenter Roeck <linux@roeck-us.net> wrote:

> On Tue, Jul 10, 2018 at 04:48:21PM +0300, Kirill A. Shutemov wrote:
> > 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@linux.intel.com>
> 
> This patch causes two of my qemu tests to fail:
> 	arm:mps2-an385:mps2_defconfig:mps2-an385
> 	xtensa:de212:kc705-nommu:nommu_kc705_defconfig
> 
> Both are nommu configurations.
> 
> Reverting the patch fixes the problem. Bisect log is attached for reference.

Thanks.  And there's the /dev/ion sysbot bug report.

mm-drop-unneeded-vm_ops-checks.patch needs some more work - let's drop it
for now.
diff mbox

Patch

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);