Merge branch 'akpm' (patches from Andrew)

Merge misc updates from Andrew Morton:

 - a few random little subsystems

 - almost all of the MM patches which are staged ahead of linux-next
   material. I'll trickle to post-linux-next work in as the dependents
   get merged up.

Subsystems affected by this patch series: kthread, kbuild, ide, ntfs,
ocfs2, arch, and mm (slab-generic, slab, slub, dax, debug, pagecache,
gup, swap, shmem, memcg, pagemap, mremap, hmm, vmalloc, documentation,
kasan, pagealloc, memory-failure, hugetlb, vmscan, z3fold, compaction,
oom-kill, migration, cma, page-poison, userfaultfd, zswap, zsmalloc,
uaccess, zram, and cleanups).

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (200 commits)
  mm: cleanup kstrto*() usage
  mm: fix fall-through warnings for Clang
  mm: slub: convert sysfs sprintf family to sysfs_emit/sysfs_emit_at
  mm: shmem: convert shmem_enabled_show to use sysfs_emit_at
  mm:backing-dev: use sysfs_emit in macro defining functions
  mm: huge_memory: convert remaining use of sprintf to sysfs_emit and neatening
  mm: use sysfs_emit for struct kobject * uses
  mm: fix kernel-doc markups
  zram: break the strict dependency from lzo
  zram: add stat to gather incompressible pages since zram set up
  zram: support page writeback
  mm/process_vm_access: remove redundant initialization of iov_r
  mm/zsmalloc.c: rework the list_add code in insert_zspage()
  mm/zswap: move to use crypto_acomp API for hardware acceleration
  mm/zswap: fix passing zero to 'PTR_ERR' warning
  mm/zswap: make struct kernel_param_ops definitions const
  userfaultfd/selftests: hint the test runner on required privilege
  userfaultfd/selftests: fix retval check for userfaultfd_open()
  userfaultfd/selftests: always dump something in modes
  userfaultfd: selftests: make __{s,u}64 format specifiers portable
  ...

1 files changed, 22 insertions, 7 deletions

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 1b697208d661..66a33e418940 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -42,7 +42,7 @@ static DEFINE_IDR(zram_index_idr);
 static DEFINE_MUTEX(zram_index_mutex);
 
 static int zram_major;
-static const char *default_compressor = "lzo-rle";
+static const char *default_compressor = CONFIG_ZRAM_DEF_COMP;
 
 /* Module params (documentation at end) */
 static unsigned int num_devices = 1;
@@ -620,15 +620,19 @@ static int read_from_bdev_async(struct zram *zram, struct bio_vec *bvec,
 	return 1;
 }
 
+#define PAGE_WB_SIG "page_index="
+
+#define PAGE_WRITEBACK 0
 #define HUGE_WRITEBACK 1
 #define IDLE_WRITEBACK 2
 
+
 static ssize_t writeback_store(struct device *dev,
 		struct device_attribute *attr, const char *buf, size_t len)
 {
 	struct zram *zram = dev_to_zram(dev);
 	unsigned long nr_pages = zram->disksize >> PAGE_SHIFT;
-	unsigned long index;
+	unsigned long index = 0;
 	struct bio bio;
 	struct bio_vec bio_vec;
 	struct page *page;
@@ -640,8 +644,17 @@ static ssize_t writeback_store(struct device *dev,
 		mode = IDLE_WRITEBACK;
 	else if (sysfs_streq(buf, "huge"))
 		mode = HUGE_WRITEBACK;
-	else
-		return -EINVAL;
+	else {
+		if (strncmp(buf, PAGE_WB_SIG, sizeof(PAGE_WB_SIG) - 1))
+			return -EINVAL;
+
+		ret = kstrtol(buf + sizeof(PAGE_WB_SIG) - 1, 10, &index);
+		if (ret || index >= nr_pages)
+			return -EINVAL;
+
+		nr_pages = 1;
+		mode = PAGE_WRITEBACK;
+	}
 
 	down_read(&zram->init_lock);
 	if (!init_done(zram)) {
@@ -660,7 +673,7 @@ static ssize_t writeback_store(struct device *dev,
 		goto release_init_lock;
 	}
 
-	for (index = 0; index < nr_pages; index++) {
+	while (nr_pages--) {
 		struct bio_vec bvec;
 
 		bvec.bv_page = page;
@@ -1071,7 +1084,7 @@ static ssize_t mm_stat_show(struct device *dev,
 	max_used = atomic_long_read(&zram->stats.max_used_pages);
 
 	ret = scnprintf(buf, PAGE_SIZE,
-			"%8llu %8llu %8llu %8lu %8ld %8llu %8lu %8llu\n",
+			"%8llu %8llu %8llu %8lu %8ld %8llu %8lu %8llu %8llu\n",
 			orig_size << PAGE_SHIFT,
 			(u64)atomic64_read(&zram->stats.compr_data_size),
 			mem_used << PAGE_SHIFT,
@@ -1079,7 +1092,8 @@ static ssize_t mm_stat_show(struct device *dev,
 			max_used << PAGE_SHIFT,
 			(u64)atomic64_read(&zram->stats.same_pages),
 			pool_stats.pages_compacted,
-			(u64)atomic64_read(&zram->stats.huge_pages));
+			(u64)atomic64_read(&zram->stats.huge_pages),
+			(u64)atomic64_read(&zram->stats.huge_pages_since));
 	up_read(&zram->init_lock);
 
 	return ret;
@@ -1411,6 +1425,7 @@ out:
 	if (comp_len == PAGE_SIZE) {
 		zram_set_flag(zram, index, ZRAM_HUGE);
 		atomic64_inc(&zram->stats.huge_pages);
+		atomic64_inc(&zram->stats.huge_pages_since);
 	}
 
 	if (flags) {