Merge tag 'mm-stable-2023-04-27-15-30' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:

 - Nick Piggin's "shoot lazy tlbs" series, to improve the peformance of
   switching from a user process to a kernel thread.

 - More folio conversions from Kefeng Wang, Zhang Peng and Pankaj
   Raghav.

 - zsmalloc performance improvements from Sergey Senozhatsky.

 - Yue Zhao has found and fixed some data race issues around the
   alteration of memcg userspace tunables.

 - VFS rationalizations from Christoph Hellwig:
     - removal of most of the callers of write_one_page()
     - make __filemap_get_folio()'s return value more useful

 - Luis Chamberlain has changed tmpfs so it no longer requires swap
   backing. Use `mount -o noswap'.

 - Qi Zheng has made the slab shrinkers operate locklessly, providing
   some scalability benefits.

 - Keith Busch has improved dmapool's performance, making part of its
   operations O(1) rather than O(n).

 - Peter Xu adds the UFFD_FEATURE_WP_UNPOPULATED feature to userfaultd,
   permitting userspace to wr-protect anon memory unpopulated ptes.

 - Kirill Shutemov has changed MAX_ORDER's meaning to be inclusive
   rather than exclusive, and has fixed a bunch of errors which were
   caused by its unintuitive meaning.

 - Axel Rasmussen give userfaultfd the UFFDIO_CONTINUE_MODE_WP feature,
   which causes minor faults to install a write-protected pte.

 - Vlastimil Babka has done some maintenance work on vma_merge():
   cleanups to the kernel code and improvements to our userspace test
   harness.

 - Cleanups to do_fault_around() by Lorenzo Stoakes.

 - Mike Rapoport has moved a lot of initialization code out of various
   mm/ files and into mm/mm_init.c.

 - Lorenzo Stoakes removd vmf_insert_mixed_prot(), which was added for
   DRM, but DRM doesn't use it any more.

 - Lorenzo has also coverted read_kcore() and vread() to use iterators
   and has thereby removed the use of bounce buffers in some cases.

 - Lorenzo has also contributed further cleanups of vma_merge().

 - Chaitanya Prakash provides some fixes to the mmap selftesting code.

 - Matthew Wilcox changes xfs and afs so they no longer take sleeping
   locks in ->map_page(), a step towards RCUification of pagefaults.

 - Suren Baghdasaryan has improved mmap_lock scalability by switching to
   per-VMA locking.

 - Frederic Weisbecker has reworked the percpu cache draining so that it
   no longer causes latency glitches on cpu isolated workloads.

 - Mike Rapoport cleans up and corrects the ARCH_FORCE_MAX_ORDER Kconfig
   logic.

 - Liu Shixin has changed zswap's initialization so we no longer waste a
   chunk of memory if zswap is not being used.

 - Yosry Ahmed has improved the performance of memcg statistics
   flushing.

 - David Stevens has fixed several issues involving khugepaged,
   userfaultfd and shmem.

 - Christoph Hellwig has provided some cleanup work to zram's IO-related
   code paths.

 - David Hildenbrand has fixed up some issues in the selftest code's
   testing of our pte state changing.

 - Pankaj Raghav has made page_endio() unneeded and has removed it.

 - Peter Xu contributed some rationalizations of the userfaultfd
   selftests.

 - Yosry Ahmed has fixed an issue around memcg's page recalim
   accounting.

 - Chaitanya Prakash has fixed some arm-related issues in the
   selftests/mm code.

 - Longlong Xia has improved the way in which KSM handles hwpoisoned
   pages.

 - Peter Xu fixes a few issues with uffd-wp at fork() time.

 - Stefan Roesch has changed KSM so that it may now be used on a
   per-process and per-cgroup basis.

* tag 'mm-stable-2023-04-27-15-30' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (369 commits)
  mm,unmap: avoid flushing TLB in batch if PTE is inaccessible
  shmem: restrict noswap option to initial user namespace
  mm/khugepaged: fix conflicting mods to collapse_file()
  sparse: remove unnecessary 0 values from rc
  mm: move 'mmap_min_addr' logic from callers into vm_unmapped_area()
  hugetlb: pte_alloc_huge() to replace huge pte_alloc_map()
  maple_tree: fix allocation in mas_sparse_area()
  mm: do not increment pgfault stats when page fault handler retries
  zsmalloc: allow only one active pool compaction context
  selftests/mm: add new selftests for KSM
  mm: add new KSM process and sysfs knobs
  mm: add new api to enable ksm per process
  mm: shrinkers: fix debugfs file permissions
  mm: don't check VMA write permissions if the PTE/PMD indicates write permissions
  migrate_pages_batch: fix statistics for longterm pin retry
  userfaultfd: use helper function range_in_vma()
  lib/show_mem.c: use for_each_populated_zone() simplify code
  mm: correct arg in reclaim_pages()/reclaim_clean_pages_from_list()
  fs/buffer: convert create_page_buffers to folio_create_buffers
  fs/buffer: add folio_create_empty_buffers helper
  ...

6 files changed, 30 insertions, 28 deletions

diff --git a/fs/afs/dir.c b/fs/afs/dir.c
index 82690d1dd49a..f92b9e62d567 100644
--- a/fs/afs/dir.c
+++ b/fs/afs/dir.c
@@ -319,16 +319,16 @@ expand:
 		struct folio *folio;
 
 		folio = filemap_get_folio(mapping, i);
-		if (!folio) {
+		if (IS_ERR(folio)) {
 			if (test_and_clear_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))
 				afs_stat_v(dvnode, n_inval);
-
-			ret = -ENOMEM;
 			folio = __filemap_get_folio(mapping,
 						    i, FGP_LOCK | FGP_CREAT,
 						    mapping->gfp_mask);
-			if (!folio)
+			if (IS_ERR(folio)) {
+				ret = PTR_ERR(folio);
 				goto error;
+			}
 			folio_attach_private(folio, (void *)1);
 			folio_unlock(folio);
 		}
@@ -524,7 +524,7 @@ static int afs_dir_iterate(struct inode *dir, struct dir_context *ctx,
 		 */
 		folio = __filemap_get_folio(dir->i_mapping, ctx->pos / PAGE_SIZE,
 					    FGP_ACCESSED, 0);
-		if (!folio) {
+		if (IS_ERR(folio)) {
 			ret = afs_bad(dvnode, afs_file_error_dir_missing_page);
 			break;
 		}
diff --git a/fs/afs/dir_edit.c b/fs/afs/dir_edit.c
index 0ab7752d1b75..f0eddccbdd95 100644
--- a/fs/afs/dir_edit.c
+++ b/fs/afs/dir_edit.c
@@ -115,7 +115,7 @@ static struct folio *afs_dir_get_folio(struct afs_vnode *vnode, pgoff_t index)
 	folio = __filemap_get_folio(mapping, index,
 				    FGP_LOCK | FGP_ACCESSED | FGP_CREAT,
 				    mapping->gfp_mask);
-	if (!folio)
+	if (IS_ERR(folio))
 		clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
 	else if (folio && !folio_test_private(folio))
 		folio_attach_private(folio, (void *)1);
diff --git a/fs/afs/file.c b/fs/afs/file.c
index 68d6d5dc608d..719b31374879 100644
--- a/fs/afs/file.c
+++ b/fs/afs/file.c
@@ -569,20 +569,10 @@ static void afs_vm_close(struct vm_area_struct *vma)
 static vm_fault_t afs_vm_map_pages(struct vm_fault *vmf, pgoff_t start_pgoff, pgoff_t end_pgoff)
 {
 	struct afs_vnode *vnode = AFS_FS_I(file_inode(vmf->vma->vm_file));
-	struct afs_file *af = vmf->vma->vm_file->private_data;
 
-	switch (afs_validate(vnode, af->key)) {
-	case 0:
+	if (afs_pagecache_valid(vnode))
 		return filemap_map_pages(vmf, start_pgoff, end_pgoff);
-	case -ENOMEM:
-		return VM_FAULT_OOM;
-	case -EINTR:
-	case -ERESTARTSYS:
-		return VM_FAULT_RETRY;
-	case -ESTALE:
-	default:
-		return VM_FAULT_SIGBUS;
-	}
+	return 0;
 }
 
 static ssize_t afs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
diff --git a/fs/afs/inode.c b/fs/afs/inode.c
index 0167e96e5198..b1bdffd5e888 100644
--- a/fs/afs/inode.c
+++ b/fs/afs/inode.c
@@ -668,6 +668,24 @@ bool afs_check_validity(struct afs_vnode *vnode)
 }
 
 /*
+ * Returns true if the pagecache is still valid.  Does not sleep.
+ */
+bool afs_pagecache_valid(struct afs_vnode *vnode)
+{
+	if (unlikely(test_bit(AFS_VNODE_DELETED, &vnode->flags))) {
+		if (vnode->netfs.inode.i_nlink)
+			clear_nlink(&vnode->netfs.inode);
+		return true;
+	}
+
+	if (test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags) &&
+	    afs_check_validity(vnode))
+		return true;
+
+	return false;
+}
+
+/*
  * validate a vnode/inode
  * - there are several things we need to check
  *   - parent dir data changes (rm, rmdir, rename, mkdir, create, link,
@@ -684,14 +702,7 @@ int afs_validate(struct afs_vnode *vnode, struct key *key)
 	       vnode->fid.vid, vnode->fid.vnode, vnode->flags,
 	       key_serial(key));
 
-	if (unlikely(test_bit(AFS_VNODE_DELETED, &vnode->flags))) {
-		if (vnode->netfs.inode.i_nlink)
-			clear_nlink(&vnode->netfs.inode);
-		goto valid;
-	}
-
-	if (test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags) &&
-	    afs_check_validity(vnode))
+	if (afs_pagecache_valid(vnode))
 		goto valid;
 
 	down_write(&vnode->validate_lock);
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index ad8523d0d038..5c95df6621f9 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -1171,6 +1171,7 @@ extern struct inode *afs_iget(struct afs_operation *, struct afs_vnode_param *);
 extern struct inode *afs_root_iget(struct super_block *, struct key *);
 extern bool afs_check_validity(struct afs_vnode *);
 extern int afs_validate(struct afs_vnode *, struct key *);
+bool afs_pagecache_valid(struct afs_vnode *);
 extern int afs_getattr(struct mnt_idmap *idmap, const struct path *,
 		       struct kstat *, u32, unsigned int);
 extern int afs_setattr(struct mnt_idmap *idmap, struct dentry *, struct iattr *);
diff --git a/fs/afs/write.c b/fs/afs/write.c
index 571f3b9a417e..c822d6006033 100644
--- a/fs/afs/write.c
+++ b/fs/afs/write.c
@@ -232,7 +232,7 @@ static void afs_kill_pages(struct address_space *mapping,
 		_debug("kill %lx (to %lx)", index, last);
 
 		folio = filemap_get_folio(mapping, index);
-		if (!folio) {
+		if (IS_ERR(folio)) {
 			next = index + 1;
 			continue;
 		}
@@ -270,7 +270,7 @@ static void afs_redirty_pages(struct writeback_control *wbc,
 		_debug("redirty %llx @%llx", len, start);
 
 		folio = filemap_get_folio(mapping, index);
-		if (!folio) {
+		if (IS_ERR(folio)) {
 			next = index + 1;
 			continue;
 		}