Merge branch 'akpm' (patches from Andrew)

Merge some more updates from Andrew Morton:

 - various hotfixes and minor things

 - hch's use_mm/unuse_mm clearnups

Subsystems affected by this patch series: mm/hugetlb, scripts, kcov,
lib, nilfs, checkpatch, lib, mm/debug, ocfs2, lib, misc.

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  kernel: set USER_DS in kthread_use_mm
  kernel: better document the use_mm/unuse_mm API contract
  kernel: move use_mm/unuse_mm to kthread.c
  kernel: move use_mm/unuse_mm to kthread.c
  stacktrace: cleanup inconsistent variable type
  lib: test get_count_order/long in test_bitops.c
  mm: add comments on pglist_data zones
  ocfs2: fix spelling mistake and grammar
  mm/debug_vm_pgtable: fix kernel crash by checking for THP support
  lib: fix bitmap_parse() on 64-bit big endian archs
  checkpatch: correct check for kernel parameters doc
  nilfs2: fix null pointer dereference at nilfs_segctor_do_construct()
  lib/lz4/lz4_decompress.c: document deliberate use of `&'
  kcov: check kcov_softirq in kcov_remote_stop()
  scripts/spelling: add a few more typos
  khugepaged: selftests: fix timeout condition in wait_for_scan()

5 files changed, 10 insertions, 19 deletions

diff --git a/fs/aio.c b/fs/aio.c
index 7e079137fdcf..7ecddc2f38db 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -27,7 +27,6 @@
 #include <linux/file.h>
 #include <linux/mm.h>
 #include <linux/mman.h>
-#include <linux/mmu_context.h>
 #include <linux/percpu.h>
 #include <linux/slab.h>
 #include <linux/timer.h>
diff --git a/fs/io-wq.c b/fs/io-wq.c
index 4023c9846860..a5e90ac39e4d 100644
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -10,7 +10,6 @@
 #include <linux/errno.h>
 #include <linux/sched/signal.h>
 #include <linux/mm.h>
-#include <linux/mmu_context.h>
 #include <linux/sched/mm.h>
 #include <linux/percpu.h>
 #include <linux/slab.h>
@@ -170,8 +169,7 @@ static bool __io_worker_unuse(struct io_wqe *wqe, struct io_worker *worker)
 			dropped_lock = true;
 		}
 		__set_current_state(TASK_RUNNING);
-		set_fs(KERNEL_DS);
-		unuse_mm(worker->mm);
+		kthread_unuse_mm(worker->mm);
 		mmput(worker->mm);
 		worker->mm = NULL;
 	}
@@ -418,18 +416,15 @@ static struct io_wq_work *io_get_next_work(struct io_wqe *wqe)
 static void io_wq_switch_mm(struct io_worker *worker, struct io_wq_work *work)
 {
 	if (worker->mm) {
-		unuse_mm(worker->mm);
+		kthread_unuse_mm(worker->mm);
 		mmput(worker->mm);
 		worker->mm = NULL;
 	}
-	if (!work->mm) {
-		set_fs(KERNEL_DS);
+	if (!work->mm)
 		return;
-	}
+
 	if (mmget_not_zero(work->mm)) {
-		use_mm(work->mm);
-		if (!worker->mm)
-			set_fs(USER_DS);
+		kthread_use_mm(work->mm);
 		worker->mm = work->mm;
 		/* hang on to this mm */
 		work->mm = NULL;
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 9fb0dc6033ba..26f7bc941d01 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -55,7 +55,6 @@
 #include <linux/fdtable.h>
 #include <linux/mm.h>
 #include <linux/mman.h>
-#include <linux/mmu_context.h>
 #include <linux/percpu.h>
 #include <linux/slab.h>
 #include <linux/kthread.h>
@@ -5867,7 +5866,7 @@ static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req,
 	if (io_op_defs[req->opcode].needs_mm && !current->mm) {
 		if (unlikely(!mmget_not_zero(ctx->sqo_mm)))
 			return -EFAULT;
-		use_mm(ctx->sqo_mm);
+		kthread_use_mm(ctx->sqo_mm);
 	}
 
 	sqe_flags = READ_ONCE(sqe->flags);
@@ -5981,7 +5980,7 @@ static inline void io_sq_thread_drop_mm(struct io_ring_ctx *ctx)
 	struct mm_struct *mm = current->mm;
 
 	if (mm) {
-		unuse_mm(mm);
+		kthread_unuse_mm(mm);
 		mmput(mm);
 	}
 }
@@ -5990,15 +5989,12 @@ static int io_sq_thread(void *data)
 {
 	struct io_ring_ctx *ctx = data;
 	const struct cred *old_cred;
-	mm_segment_t old_fs;
 	DEFINE_WAIT(wait);
 	unsigned long timeout;
 	int ret = 0;
 
 	complete(&ctx->sq_thread_comp);
 
-	old_fs = get_fs();
-	set_fs(USER_DS);
 	old_cred = override_creds(ctx->creds);
 
 	timeout = jiffies + ctx->sq_thread_idle;
@@ -6103,7 +6099,6 @@ static int io_sq_thread(void *data)
 	if (current->task_works)
 		task_work_run();
 
-	set_fs(old_fs);
 	io_sq_thread_drop_mm(ctx);
 	revert_creds(old_cred);
 
diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c
index 445eef41bfaf..91b58c897f92 100644
--- a/fs/nilfs2/segment.c
+++ b/fs/nilfs2/segment.c
@@ -2780,6 +2780,8 @@ int nilfs_attach_log_writer(struct super_block *sb, struct nilfs_root *root)
 	if (!nilfs->ns_writer)
 		return -ENOMEM;
 
+	inode_attach_wb(nilfs->ns_bdev->bd_inode, NULL);
+
 	err = nilfs_segctor_start_thread(nilfs->ns_writer);
 	if (err) {
 		kfree(nilfs->ns_writer);
diff --git a/fs/ocfs2/mmap.c b/fs/ocfs2/mmap.c
index 3a44e461828a..25cabbfe87fc 100644
--- a/fs/ocfs2/mmap.c
+++ b/fs/ocfs2/mmap.c
@@ -62,7 +62,7 @@ static vm_fault_t __ocfs2_page_mkwrite(struct file *file,
 	last_index = (size - 1) >> PAGE_SHIFT;
 
 	/*
-	 * There are cases that lead to the page no longer bebongs to the
+	 * There are cases that lead to the page no longer belonging to the
 	 * mapping.
 	 * 1) pagecache truncates locally due to memory pressure.
 	 * 2) pagecache truncates when another is taking EX lock against