Merge tag 'mm-stable-2022-05-25' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:
 "Almost all of MM here. A few things are still getting finished off,
  reviewed, etc.

   - Yang Shi has improved the behaviour of khugepaged collapsing of
     readonly file-backed transparent hugepages.

   - Johannes Weiner has arranged for zswap memory use to be tracked and
     managed on a per-cgroup basis.

   - Munchun Song adds a /proc knob ("hugetlb_optimize_vmemmap") for
     runtime enablement of the recent huge page vmemmap optimization
     feature.

   - Baolin Wang contributes a series to fix some issues around hugetlb
     pagetable invalidation.

   - Zhenwei Pi has fixed some interactions between hwpoisoned pages and
     virtualization.

   - Tong Tiangen has enabled the use of the presently x86-only
     page_table_check debugging feature on arm64 and riscv.

   - David Vernet has done some fixup work on the memcg selftests.

   - Peter Xu has taught userfaultfd to handle write protection faults
     against shmem- and hugetlbfs-backed files.

   - More DAMON development from SeongJae Park - adding online tuning of
     the feature and support for monitoring of fixed virtual address
     ranges. Also easier discovery of which monitoring operations are
     available.

   - Nadav Amit has done some optimization of TLB flushing during
     mprotect().

   - Neil Brown continues to labor away at improving our swap-over-NFS
     support.

   - David Hildenbrand has some fixes to anon page COWing versus
     get_user_pages().

   - Peng Liu fixed some errors in the core hugetlb code.

   - Joao Martins has reduced the amount of memory consumed by
     device-dax's compound devmaps.

   - Some cleanups of the arch-specific pagemap code from Anshuman
     Khandual.

   - Muchun Song has found and fixed some errors in the TLB flushing of
     transparent hugepages.

   - Roman Gushchin has done more work on the memcg selftests.

  ... and, of course, many smaller fixes and cleanups. Notably, the
  customary million cleanup serieses from Miaohe Lin"

* tag 'mm-stable-2022-05-25' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (381 commits)
  mm: kfence: use PAGE_ALIGNED helper
  selftests: vm: add the "settings" file with timeout variable
  selftests: vm: add "test_hmm.sh" to TEST_FILES
  selftests: vm: check numa_available() before operating "merge_across_nodes" in ksm_tests
  selftests: vm: add migration to the .gitignore
  selftests/vm/pkeys: fix typo in comment
  ksm: fix typo in comment
  selftests: vm: add process_mrelease tests
  Revert "mm/vmscan: never demote for memcg reclaim"
  mm/kfence: print disabling or re-enabling message
  include/trace/events/percpu.h: cleanup for "percpu: improve percpu_alloc_percpu event trace"
  include/trace/events/mmflags.h: cleanup for "tracing: incorrect gfp_t conversion"
  mm: fix a potential infinite loop in start_isolate_page_range()
  MAINTAINERS: add Muchun as co-maintainer for HugeTLB
  zram: fix Kconfig dependency warning
  mm/shmem: fix shmem folio swapoff hang
  cgroup: fix an error handling path in alloc_pagecache_max_30M()
  mm: damon: use HPAGE_PMD_SIZE
  tracing: incorrect isolate_mote_t cast in mm_vmscan_lru_isolate
  nodemask.h: fix compilation error with GCC12
  ...

1 files changed, 31 insertions, 25 deletions

diff --git a/tools/testing/selftests/cgroup/cgroup_util.c b/tools/testing/selftests/cgroup/cgroup_util.c
index 4297d580e3f8..4c52cc6f2f9c 100644
--- a/tools/testing/selftests/cgroup/cgroup_util.c
+++ b/tools/testing/selftests/cgroup/cgroup_util.c
@@ -19,6 +19,7 @@
 #include "cgroup_util.h"
 #include "../clone3/clone3_selftests.h"
 
+/* Returns read len on success, or -errno on failure. */
 static ssize_t read_text(const char *path, char *buf, size_t max_len)
 {
 	ssize_t len;
@@ -26,35 +27,29 @@ static ssize_t read_text(const char *path, char *buf, size_t max_len)
 
 	fd = open(path, O_RDONLY);
 	if (fd < 0)
-		return fd;
+		return -errno;
 
 	len = read(fd, buf, max_len - 1);
-	if (len < 0)
-		goto out;
 
-	buf[len] = 0;
-out:
+	if (len >= 0)
+		buf[len] = 0;
+
 	close(fd);
-	return len;
+	return len < 0 ? -errno : len;
 }
 
+/* Returns written len on success, or -errno on failure. */
 static ssize_t write_text(const char *path, char *buf, ssize_t len)
 {
 	int fd;
 
 	fd = open(path, O_WRONLY | O_APPEND);
 	if (fd < 0)
-		return fd;
+		return -errno;
 
 	len = write(fd, buf, len);
-	if (len < 0) {
-		close(fd);
-		return len;
-	}
-
 	close(fd);
-
-	return len;
+	return len < 0 ? -errno : len;
 }
 
 char *cg_name(const char *root, const char *name)
@@ -87,16 +82,16 @@ char *cg_control(const char *cgroup, const char *control)
 	return ret;
 }
 
+/* Returns 0 on success, or -errno on failure. */
 int cg_read(const char *cgroup, const char *control, char *buf, size_t len)
 {
 	char path[PATH_MAX];
+	ssize_t ret;
 
 	snprintf(path, sizeof(path), "%s/%s", cgroup, control);
 
-	if (read_text(path, buf, len) >= 0)
-		return 0;
-
-	return -1;
+	ret = read_text(path, buf, len);
+	return ret >= 0 ? 0 : ret;
 }
 
 int cg_read_strcmp(const char *cgroup, const char *control,
@@ -177,17 +172,15 @@ long cg_read_lc(const char *cgroup, const char *control)
 	return cnt;
 }
 
+/* Returns 0 on success, or -errno on failure. */
 int cg_write(const char *cgroup, const char *control, char *buf)
 {
 	char path[PATH_MAX];
-	ssize_t len = strlen(buf);
+	ssize_t len = strlen(buf), ret;
 
 	snprintf(path, sizeof(path), "%s/%s", cgroup, control);
-
-	if (write_text(path, buf, len) == len)
-		return 0;
-
-	return -1;
+	ret = write_text(path, buf, len);
+	return ret == len ? 0 : ret;
 }
 
 int cg_write_numeric(const char *cgroup, const char *control, long value)
@@ -547,6 +540,18 @@ int set_oom_adj_score(int pid, int score)
 	return 0;
 }
 
+int proc_mount_contains(const char *option)
+{
+	char buf[4 * PAGE_SIZE];
+	ssize_t read;
+
+	read = read_text("/proc/mounts", buf, sizeof(buf));
+	if (read < 0)
+		return read;
+
+	return strstr(buf, option) != NULL;
+}
+
 ssize_t proc_read_text(int pid, bool thread, const char *item, char *buf, size_t size)
 {
 	char path[PATH_MAX];
@@ -557,7 +562,8 @@ ssize_t proc_read_text(int pid, bool thread, const char *item, char *buf, size_t
 	else
 		snprintf(path, sizeof(path), "/proc/%d/%s", pid, item);
 
-	return read_text(path, buf, size);
+	size = read_text(path, buf, size);
+	return size < 0 ? -1 : size;
 }
 
 int proc_read_strstr(int pid, bool thread, const char *item, const char *needle)