Merge branch 'akpm' (patches from Andrew)

Merge second patchbomb from Andrew Morton:

 - most of the rest of MM

 - lots of misc things

 - procfs updates

 - printk feature work

 - updates to get_maintainer, MAINTAINERS, checkpatch

 - lib/ updates

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (96 commits)
  exit,stats: /* obey this comment */
  coredump: add __printf attribute to cn_*printf functions
  coredump: use from_kuid/kgid when formatting corename
  fs/reiserfs: remove unneeded cast
  NILFS2: support NFSv2 export
  fs/befs/btree.c: remove unneeded initializations
  fs/minix: remove unneeded cast
  init/do_mounts.c: add create_dev() failure log
  kasan: remove duplicate definition of the macro KASAN_FREE_PAGE
  fs/efs: femove unneeded cast
  checkpatch: emit "NOTE: <types>" message only once after multiple files
  checkpatch: emit an error when there's a diff in a changelog
  checkpatch: validate MODULE_LICENSE content
  checkpatch: add multi-line handling for PREFER_ETHER_ADDR_COPY
  checkpatch: suggest using eth_zero_addr() and eth_broadcast_addr()
  checkpatch: fix processing of MEMSET issues
  checkpatch: suggest using ether_addr_equal*()
  checkpatch: avoid NOT_UNIFIED_DIFF errors on cover-letter.patch files
  checkpatch: remove local from codespell path
  checkpatch: add --showfile to allow input via pipe to show filenames
  ...

16 files changed, 736 insertions, 483 deletions

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 21d13038534e..dafae6d2f7ac 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -1303,12 +1303,11 @@ const char *device_get_devnode(struct device *dev,
 		return dev_name(dev);
 
 	/* replace '!' in the name with '/' */
-	*tmp = kstrdup(dev_name(dev), GFP_KERNEL);
-	if (!*tmp)
+	s = kstrdup(dev_name(dev), GFP_KERNEL);
+	if (!s)
 		return NULL;
-	while ((s = strchr(*tmp, '!')))
-		s[0] = '/';
-	return *tmp;
+	strreplace(s, '!', '/');
+	return *tmp = s;
 }
 
 /**
diff --git a/drivers/block/zram/Kconfig b/drivers/block/zram/Kconfig
index 6489c0fd0ea6..386ba3d1a6ee 100644
--- a/drivers/block/zram/Kconfig
+++ b/drivers/block/zram/Kconfig
@@ -23,12 +23,4 @@ config ZRAM_LZ4_COMPRESS
 	default n
 	help
 	  This option enables LZ4 compression algorithm support. Compression
-	  algorithm can be changed using `comp_algorithm' device attribute.
-
-config ZRAM_DEBUG
-	bool "Compressed RAM block device debug support"
-	depends on ZRAM
-	default n
-	help
-	  This option adds additional debugging code to the compressed
-	  RAM block device driver.
+	  algorithm can be changed using `comp_algorithm' device attribute.
\ No newline at end of file
diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c
index f1ff39a3d1c1..965d1afb0eaa 100644
--- a/drivers/block/zram/zcomp.c
+++ b/drivers/block/zram/zcomp.c
@@ -274,7 +274,7 @@ ssize_t zcomp_available_show(const char *comp, char *buf)
 	int i = 0;
 
 	while (backends[i]) {
-		if (sysfs_streq(comp, backends[i]->name))
+		if (!strcmp(comp, backends[i]->name))
 			sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2,
 					"[%s] ", backends[i]->name);
 		else
@@ -286,6 +286,11 @@ ssize_t zcomp_available_show(const char *comp, char *buf)
 	return sz;
 }
 
+bool zcomp_available_algorithm(const char *comp)
+{
+	return find_backend(comp) != NULL;
+}
+
 bool zcomp_set_max_streams(struct zcomp *comp, int num_strm)
 {
 	return comp->set_max_streams(comp, num_strm);
diff --git a/drivers/block/zram/zcomp.h b/drivers/block/zram/zcomp.h
index c59d1fca72c0..46e2b9f8f1f0 100644
--- a/drivers/block/zram/zcomp.h
+++ b/drivers/block/zram/zcomp.h
@@ -51,6 +51,7 @@ struct zcomp {
 };
 
 ssize_t zcomp_available_show(const char *comp, char *buf);
+bool zcomp_available_algorithm(const char *comp);
 
 struct zcomp *zcomp_create(const char *comp, int max_strm);
 void zcomp_destroy(struct zcomp *comp);
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 6e134f4759c0..fb655e8d1e3b 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -15,10 +15,6 @@
 #define KMSG_COMPONENT "zram"
 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
 
-#ifdef CONFIG_ZRAM_DEBUG
-#define DEBUG
-#endif
-
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/bio.h>
@@ -32,12 +28,16 @@
 #include <linux/string.h>
 #include <linux/vmalloc.h>
 #include <linux/err.h>
+#include <linux/idr.h>
+#include <linux/sysfs.h>
 
 #include "zram_drv.h"
 
-/* Globals */
+static DEFINE_IDR(zram_index_idr);
+/* idr index must be protected */
+static DEFINE_MUTEX(zram_index_mutex);
+
 static int zram_major;
-static struct zram *zram_devices;
 static const char *default_compressor = "lzo";
 
 /* Module params (documentation at end) */
@@ -53,7 +53,7 @@ static inline void deprecated_attr_warn(const char *name)
 }
 
 #define ZRAM_ATTR_RO(name)						\
-static ssize_t name##_show(struct device *d,		\
+static ssize_t name##_show(struct device *d,				\
 				struct device_attribute *attr, char *b)	\
 {									\
 	struct zram *zram = dev_to_zram(d);				\
@@ -74,33 +74,117 @@ static inline struct zram *dev_to_zram(struct device *dev)
 	return (struct zram *)dev_to_disk(dev)->private_data;
 }
 
-static ssize_t compact_store(struct device *dev,
-		struct device_attribute *attr, const char *buf, size_t len)
+/* flag operations require table entry bit_spin_lock() being held */
+static int zram_test_flag(struct zram_meta *meta, u32 index,
+			enum zram_pageflags flag)
 {
-	unsigned long nr_migrated;
-	struct zram *zram = dev_to_zram(dev);
-	struct zram_meta *meta;
+	return meta->table[index].value & BIT(flag);
+}
 
-	down_read(&zram->init_lock);
-	if (!init_done(zram)) {
-		up_read(&zram->init_lock);
-		return -EINVAL;
-	}
+static void zram_set_flag(struct zram_meta *meta, u32 index,
+			enum zram_pageflags flag)
+{
+	meta->table[index].value |= BIT(flag);
+}
 
-	meta = zram->meta;
-	nr_migrated = zs_compact(meta->mem_pool);
-	atomic64_add(nr_migrated, &zram->stats.num_migrated);
-	up_read(&zram->init_lock);
+static void zram_clear_flag(struct zram_meta *meta, u32 index,
+			enum zram_pageflags flag)
+{
+	meta->table[index].value &= ~BIT(flag);
+}
 
-	return len;
+static size_t zram_get_obj_size(struct zram_meta *meta, u32 index)
+{
+	return meta->table[index].value & (BIT(ZRAM_FLAG_SHIFT) - 1);
 }
 
-static ssize_t disksize_show(struct device *dev,
-		struct device_attribute *attr, char *buf)
+static void zram_set_obj_size(struct zram_meta *meta,
+					u32 index, size_t size)
 {
-	struct zram *zram = dev_to_zram(dev);
+	unsigned long flags = meta->table[index].value >> ZRAM_FLAG_SHIFT;
 
-	return scnprintf(buf, PAGE_SIZE, "%llu\n", zram->disksize);
+	meta->table[index].value = (flags << ZRAM_FLAG_SHIFT) | size;
+}
+
+static inline int is_partial_io(struct bio_vec *bvec)
+{
+	return bvec->bv_len != PAGE_SIZE;
+}
+
+/*
+ * Check if request is within bounds and aligned on zram logical blocks.
+ */
+static inline int valid_io_request(struct zram *zram,
+		sector_t start, unsigned int size)
+{
+	u64 end, bound;
+
+	/* unaligned request */
+	if (unlikely(start & (ZRAM_SECTOR_PER_LOGICAL_BLOCK - 1)))
+		return 0;
+	if (unlikely(size & (ZRAM_LOGICAL_BLOCK_SIZE - 1)))
+		return 0;
+
+	end = start + (size >> SECTOR_SHIFT);
+	bound = zram->disksize >> SECTOR_SHIFT;
+	/* out of range range */
+	if (unlikely(start >= bound || end > bound || start > end))
+		return 0;
+
+	/* I/O request is valid */
+	return 1;
+}
+
+static void update_position(u32 *index, int *offset, struct bio_vec *bvec)
+{
+	if (*offset + bvec->bv_len >= PAGE_SIZE)
+		(*index)++;
+	*offset = (*offset + bvec->bv_len) % PAGE_SIZE;
+}
+
+static inline void update_used_max(struct zram *zram,
+					const unsigned long pages)
+{
+	unsigned long old_max, cur_max;
+
+	old_max = atomic_long_read(&zram->stats.max_used_pages);
+
+	do {
+		cur_max = old_max;
+		if (pages > cur_max)
+			old_max = atomic_long_cmpxchg(
+				&zram->stats.max_used_pages, cur_max, pages);
+	} while (old_max != cur_max);
+}
+
+static int page_zero_filled(void *ptr)
+{
+	unsigned int pos;
+	unsigned long *page;
+
+	page = (unsigned long *)ptr;
+
+	for (pos = 0; pos != PAGE_SIZE / sizeof(*page); pos++) {
+		if (page[pos])
+			return 0;
+	}
+
+	return 1;
+}
+
+static void handle_zero_page(struct bio_vec *bvec)
+{
+	struct page *page = bvec->bv_page;
+	void *user_mem;
+
+	user_mem = kmap_atomic(page);
+	if (is_partial_io(bvec))
+		memset(user_mem + bvec->bv_offset, 0, bvec->bv_len);
+	else
+		clear_page(user_mem);
+	kunmap_atomic(user_mem);
+
+	flush_dcache_page(page);
 }
 
 static ssize_t initstate_show(struct device *dev,
@@ -116,6 +200,14 @@ static ssize_t initstate_show(struct device *dev,
 	return scnprintf(buf, PAGE_SIZE, "%u\n", val);
 }
 
+static ssize_t disksize_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct zram *zram = dev_to_zram(dev);
+
+	return scnprintf(buf, PAGE_SIZE, "%llu\n", zram->disksize);
+}
+
 static ssize_t orig_data_size_show(struct device *dev,
 		struct device_attribute *attr, char *buf)
 {
@@ -143,19 +235,6 @@ static ssize_t mem_used_total_show(struct device *dev,
 	return scnprintf(buf, PAGE_SIZE, "%llu\n", val << PAGE_SHIFT);
 }
 
-static ssize_t max_comp_streams_show(struct device *dev,
-		struct device_attribute *attr, char *buf)
-{
-	int val;
-	struct zram *zram = dev_to_zram(dev);
-
-	down_read(&zram->init_lock);
-	val = zram->max_comp_streams;
-	up_read(&zram->init_lock);
-
-	return scnprintf(buf, PAGE_SIZE, "%d\n", val);
-}
-
 static ssize_t mem_limit_show(struct device *dev,
 		struct device_attribute *attr, char *buf)
 {
@@ -225,6 +304,19 @@ static ssize_t mem_used_max_store(struct device *dev,
 	return len;
 }
 
+static ssize_t max_comp_streams_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	int val;
+	struct zram *zram = dev_to_zram(dev);
+
+	down_read(&zram->init_lock);
+	val = zram->max_comp_streams;
+	up_read(&zram->init_lock);
+
+	return scnprintf(buf, PAGE_SIZE, "%d\n", val);
+}
+
 static ssize_t max_comp_streams_store(struct device *dev,
 		struct device_attribute *attr, const char *buf, size_t len)
 {
@@ -271,6 +363,8 @@ static ssize_t comp_algorithm_store(struct device *dev,
 		struct device_attribute *attr, const char *buf, size_t len)
 {
 	struct zram *zram = dev_to_zram(dev);
+	size_t sz;
+
 	down_write(&zram->init_lock);
 	if (init_done(zram)) {
 		up_write(&zram->init_lock);
@@ -278,69 +372,108 @@ static ssize_t comp_algorithm_store(struct device *dev,
 		return -EBUSY;
 	}
 	strlcpy(zram->compressor, buf, sizeof(zram->compressor));
+
+	/* ignore trailing newline */
+	sz = strlen(zram->compressor);
+	if (sz > 0 && zram->compressor[sz - 1] == '\n')
+		zram->compressor[sz - 1] = 0x00;
+
+	if (!zcomp_available_algorithm(zram->compressor))
+		len = -EINVAL;
+
 	up_write(&zram->init_lock);
 	return len;
 }
 
-/* flag operations needs meta->tb_lock */
-static int zram_test_flag(struct zram_meta *meta, u32 index,
-			enum zram_pageflags flag)
+static ssize_t compact_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t len)
 {
-	return meta->table[index].value & BIT(flag);
-}
+	unsigned long nr_migrated;
+	struct zram *zram = dev_to_zram(dev);
+	struct zram_meta *meta;
 
-static void zram_set_flag(struct zram_meta *meta, u32 index,
-			enum zram_pageflags flag)
-{
-	meta->table[index].value |= BIT(flag);
-}
+	down_read(&zram->init_lock);
+	if (!init_done(zram)) {
+		up_read(&zram->init_lock);
+		return -EINVAL;
+	}
 
-static void zram_clear_flag(struct zram_meta *meta, u32 index,
-			enum zram_pageflags flag)
-{
-	meta->table[index].value &= ~BIT(flag);
+	meta = zram->meta;
+	nr_migrated = zs_compact(meta->mem_pool);
+	atomic64_add(nr_migrated, &zram->stats.num_migrated);
+	up_read(&zram->init_lock);
+
+	return len;
 }
 
-static size_t zram_get_obj_size(struct zram_meta *meta, u32 index)
+static ssize_t io_stat_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
 {
-	return meta->table[index].value & (BIT(ZRAM_FLAG_SHIFT) - 1);
+	struct zram *zram = dev_to_zram(dev);
+	ssize_t ret;
+
+	down_read(&zram->init_lock);
+	ret = scnprintf(buf, PAGE_SIZE,
+			"%8llu %8llu %8llu %8llu\n",
+			(u64)atomic64_read(&zram->stats.failed_reads),
+			(u64)atomic64_read(&zram->stats.failed_writes),
+			(u64)atomic64_read(&zram->stats.invalid_io),
+			(u64)atomic64_read(&zram->stats.notify_free));
+	up_read(&zram->init_lock);
+
+	return ret;
 }
 
-static void zram_set_obj_size(struct zram_meta *meta,
-					u32 index, size_t size)
+static ssize_t mm_stat_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
 {
-	unsigned long flags = meta->table[index].value >> ZRAM_FLAG_SHIFT;
+	struct zram *zram = dev_to_zram(dev);
+	u64 orig_size, mem_used = 0;
+	long max_used;
+	ssize_t ret;
 
-	meta->table[index].value = (flags << ZRAM_FLAG_SHIFT) | size;
+	down_read(&zram->init_lock);
+	if (init_done(zram))
+		mem_used = zs_get_total_pages(zram->meta->mem_pool);
+
+	orig_size = atomic64_read(&zram->stats.pages_stored);
+	max_used = atomic_long_read(&zram->stats.max_used_pages);
+
+	ret = scnprintf(buf, PAGE_SIZE,
+			"%8llu %8llu %8llu %8lu %8ld %8llu %8llu\n",
+			orig_size << PAGE_SHIFT,
+			(u64)atomic64_read(&zram->stats.compr_data_size),
+			mem_used << PAGE_SHIFT,
+			zram->limit_pages << PAGE_SHIFT,
+			max_used << PAGE_SHIFT,
+			(u64)atomic64_read(&zram->stats.zero_pages),
+			(u64)atomic64_read(&zram->stats.num_migrated));
+	up_read(&zram->init_lock);
+
+	return ret;
 }
 
-static inline int is_partial_io(struct bio_vec *bvec)
+static DEVICE_ATTR_RO(io_stat);
+static DEVICE_ATTR_RO(mm_stat);
+ZRAM_ATTR_RO(num_reads);
+ZRAM_ATTR_RO(num_writes);
+ZRAM_ATTR_RO(failed_reads);
+ZRAM_ATTR_RO(failed_writes);
+ZRAM_ATTR_RO(invalid_io);
+ZRAM_ATTR_RO(notify_free);
+ZRAM_ATTR_RO(zero_pages);
+ZRAM_ATTR_RO(compr_data_size);
+
+static inline bool zram_meta_get(struct zram *zram)
 {
-	return bvec->bv_len != PAGE_SIZE;
+	if (atomic_inc_not_zero(&zram->refcount))
+		return true;
+	return false;
 }
 
-/*
- * Check if request is within bounds and aligned on zram logical blocks.
- */
-static inline int valid_io_request(struct zram *zram,
-		sector_t start, unsigned int size)
+static inline void zram_meta_put(struct zram *zram)
 {
-	u64 end, bound;
-
-	/* unaligned request */
-	if (unlikely(start & (ZRAM_SECTOR_PER_LOGICAL_BLOCK - 1)))
-		return 0;
-	if (unlikely(size & (ZRAM_LOGICAL_BLOCK_SIZE - 1)))
-		return 0;
-
-	end = start + (size >> SECTOR_SHIFT);
-	bound = zram->disksize >> SECTOR_SHIFT;
-	/* out of range range */
-	if (unlikely(start >= bound || end > bound || start > end))
-		return 0;
-
-	/* I/O request is valid */
-	return 1;
+	atomic_dec(&zram->refcount);
 }
 
 static void zram_meta_free(struct zram_meta *meta, u64 disksize)
@@ -394,56 +527,6 @@ out_error:
 	return NULL;
 }
 
-static inline bool zram_meta_get(struct zram *zram)
-{
-	if (atomic_inc_not_zero(&zram->refcount))
-		return true;
-	return false;
-}
-
-static inline void zram_meta_put(struct zram *zram)
-{
-	atomic_dec(&zram->refcount);
-}
-
-static void update_position(u32 *index, int *offset, struct bio_vec *bvec)
-{
-	if (*offset + bvec->bv_len >= PAGE_SIZE)
-		(*index)++;
-	*offset = (*offset + bvec->bv_len) % PAGE_SIZE;
-}
-
-static int page_zero_filled(void *ptr)
-{
-	unsigned int pos;
-	unsigned long *page;
-
-	page = (unsigned long *)ptr;
-
-	for (pos = 0; pos != PAGE_SIZE / sizeof(*page); pos++) {
-		if (page[pos])
-			return 0;
-	}
-
-	return 1;
-}
-
-static void handle_zero_page(struct bio_vec *bvec)
-{
-	struct page *page = bvec->bv_page;
-	void *user_mem;
-
-	user_mem = kmap_atomic(page);
-	if (is_partial_io(bvec))
-		memset(user_mem + bvec->bv_offset, 0, bvec->bv_len);
-	else
-		clear_page(user_mem);
-	kunmap_atomic(user_mem);
-
-	flush_dcache_page(page);
-}
-
-
 /*
  * To protect concurrent access to the same index entry,
  * caller should hold this table index entry's bit_spinlock to
@@ -561,21 +644,6 @@ out_cleanup:
 	return ret;
 }
 
-static inline void update_used_max(struct zram *zram,
-					const unsigned long pages)
-{
-	unsigned long old_max, cur_max;
-
-	old_max = atomic_long_read(&zram->stats.max_used_pages);
-
-	do {
-		cur_max = old_max;
-		if (pages > cur_max)
-			old_max = atomic_long_cmpxchg(
-				&zram->stats.max_used_pages, cur_max, pages);
-	} while (old_max != cur_max);
-}
-
 static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
 			   int offset)
 {
@@ -585,8 +653,7 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
 	struct page *page;
 	unsigned char *user_mem, *cmem, *src, *uncmem = NULL;
 	struct zram_meta *meta = zram->meta;
-	struct zcomp_strm *zstrm;
-	bool locked = false;
+	struct zcomp_strm *zstrm = NULL;
 	unsigned long alloced_pages;
 
 	page = bvec->bv_page;
@@ -606,7 +673,6 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
 	}
 
 	zstrm = zcomp_strm_find(zram->comp);
-	locked = true;
 	user_mem = kmap_atomic(page);
 
 	if (is_partial_io(bvec)) {
@@ -678,7 +744,7 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
 	}
 
 	zcomp_strm_release(zram->comp, zstrm);
-	locked = false;
+	zstrm = NULL;
 	zs_unmap_object(meta->mem_pool, handle);
 
 	/*
@@ -696,42 +762,13 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
 	atomic64_add(clen, &zram->stats.compr_data_size);
 	atomic64_inc(&zram->stats.pages_stored);
 out:
-	if (locked)
+	if (zstrm)
 		zcomp_strm_release(zram->comp, zstrm);
 	if (is_partial_io(bvec))
 		kfree(uncmem);
 	return ret;
 }
 
-static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 index,
-			int offset, int rw)
-{
-	unsigned long start_time = jiffies;
-	int ret;
-
-	generic_start_io_acct(rw, bvec->bv_len >> SECTOR_SHIFT,
-			&zram->disk->part0);
-
-	if (rw == READ) {
-		atomic64_inc(&zram->stats.num_reads);
-		ret = zram_bvec_read(zram, bvec, index, offset);
-	} else {
-		atomic64_inc(&zram->stats.num_writes);
-		ret = zram_bvec_write(zram, bvec, index, offset);
-	}
-
-	generic_end_io_acct(rw, &zram->disk->part0, start_time);
-
-	if (unlikely(ret)) {
-		if (rw == READ)
-			atomic64_inc(&zram->stats.failed_reads);
-		else
-			atomic64_inc(&zram->stats.failed_writes);
-	}
-
-	return ret;
-}
-
 /*
  * zram_bio_discard - handler on discard request
  * @index: physical block index in PAGE_SIZE units
@@ -771,151 +808,32 @@ static void zram_bio_discard(struct zram *zram, u32 index,
 	}
 }
 
-static void zram_reset_device(struct zram *zram)
-{
-	struct zram_meta *meta;
-	struct zcomp *comp;
-	u64 disksize;
-
-	down_write(&zram->init_lock);
-
-	zram->limit_pages = 0;
-
-	if (!init_done(zram)) {
-		up_write(&zram->init_lock);
-		return;
-	}
-
-	meta = zram->meta;
-	comp = zram->comp;
-	disksize = zram->disksize;
-	/*
-	 * Refcount will go down to 0 eventually and r/w handler
-	 * cannot handle further I/O so it will bail out by
-	 * check zram_meta_get.
-	 */
-	zram_meta_put(zram);
-	/*
-	 * We want to free zram_meta in process context to avoid
-	 * deadlock between reclaim path and any other locks.
-	 */
-	wait_event(zram->io_done, atomic_read(&zram->refcount) == 0);
-
-	/* Reset stats */
-	memset(&zram->stats, 0, sizeof(zram->stats));
-	zram->disksize = 0;
-	zram->max_comp_streams = 1;
-
-	set_capacity(zram->disk, 0);
-	part_stat_set_all(&zram->disk->part0, 0);
-
-	up_write(&zram->init_lock);
-	/* I/O operation under all of CPU are done so let's free */
-	zram_meta_free(meta, disksize);
-	zcomp_destroy(comp);
-}
-
-static ssize_t disksize_store(struct device *dev,
-		struct device_attribute *attr, const char *buf, size_t len)
-{
-	u64 disksize;
-	struct zcomp *comp;
-	struct zram_meta *meta;
-	struct zram *zram = dev_to_zram(dev);
-	int err;
-
-	disksize = memparse(buf, NULL);
-	if (!disksize)
-		return -EINVAL;
-
-	disksize = PAGE_ALIGN(disksize);
-	meta = zram_meta_alloc(zram->disk->first_minor, disksize);
-	if (!meta)
-		return -ENOMEM;
-
-	comp = zcomp_create(zram->compressor, zram->max_comp_streams);
-	if (IS_ERR(comp)) {
-		pr_info("Cannot initialise %s compressing backend\n",
-				zram->compressor);
-		err = PTR_ERR(comp);
-		goto out_free_meta;
-	}
-
-	down_write(&zram->init_lock);
-	if (init_done(zram)) {
-		pr_info("Cannot change disksize for initialized device\n");
-		err = -EBUSY;
-		goto out_destroy_comp;
-	}
-
-	init_waitqueue_head(&zram->io_done);
-	atomic_set(&zram->refcount, 1);
-	zram->meta = meta;
-	zram->comp = comp;
-	zram->disksize = disksize;
-	set_capacity(zram->disk, zram->disksize >> SECTOR_SHIFT);
-	up_write(&zram->init_lock);
-
-	/*
-	 * Revalidate disk out of the init_lock to avoid lockdep splat.
-	 * It's okay because disk's capacity is protected by init_lock
-	 * so that revalidate_disk always sees up-to-date capacity.
-	 */
-	revalidate_disk(zram->disk);
-
-	return len;
-
-out_destroy_comp:
-	up_write(&zram->init_lock);
-	zcomp_destroy(comp);
-out_free_meta:
-	zram_meta_free(meta, disksize);
-	return err;
-}
-
-static ssize_t reset_store(struct device *dev,
-		struct device_attribute *attr, const char *buf, size_t len)
+static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 index,
+			int offset, int rw)
 {
+	unsigned long start_time = jiffies;
 	int ret;
-	unsigned short do_reset;
-	struct zram *zram;
-	struct block_device *bdev;
 
-	zram = dev_to_zram(dev);
-	bdev = bdget_disk(zram->disk, 0);
-
-	if (!bdev)
-		return -ENOMEM;
+	generic_start_io_acct(rw, bvec->bv_len >> SECTOR_SHIFT,
+			&zram->disk->part0);
 
-	mutex_lock(&bdev->bd_mutex);
-	/* Do not reset an active device! */
-	if (bdev->bd_openers) {
-		ret = -EBUSY;
-		goto out;
+	if (rw == READ) {
+		atomic64_inc(&zram->stats.num_reads);
+		ret = zram_bvec_read(zram, bvec, index, offset);
+	} else {
+		atomic64_inc(&zram->stats.num_writes);
+		ret = zram_bvec_write(zram, bvec, index, offset);
 	}
 
-	ret = kstrtou16(buf, 10, &do_reset);
-	if (ret)
-		goto out;
+	generic_end_io_acct(rw, &zram->disk->part0, start_time);
 
-	if (!do_reset) {
-		ret = -EINVAL;
-		goto out;
+	if (unlikely(ret)) {
+		if (rw == READ)
+			atomic64_inc(&zram->stats.failed_reads);
+		else
+			atomic64_inc(&zram->stats.failed_writes);
 	}
 
-	/* Make sure all pending I/O is finished */
-	fsync_bdev(bdev);
-	zram_reset_device(zram);
-
-	mutex_unlock(&bdev->bd_mutex);
-	revalidate_disk(zram->disk);
-	bdput(bdev);
-
-	return len;
-
-out:
-	mutex_unlock(&bdev->bd_mutex);
-	bdput(bdev);
 	return ret;
 }
 
@@ -1055,80 +973,185 @@ out:
 	return err;
 }
 
-static const struct block_device_operations zram_devops = {
-	.swap_slot_free_notify = zram_slot_free_notify,
-	.rw_page = zram_rw_page,
-	.owner = THIS_MODULE
-};
+static void zram_reset_device(struct zram *zram)
+{
+	struct zram_meta *meta;
+	struct zcomp *comp;
+	u64 disksize;
 
-static DEVICE_ATTR_WO(compact);
-static DEVICE_ATTR_RW(disksize);
-static DEVICE_ATTR_RO(initstate);
-static DEVICE_ATTR_WO(reset);
-static DEVICE_ATTR_RO(orig_data_size);
-static DEVICE_ATTR_RO(mem_used_total);
-static DEVICE_ATTR_RW(mem_limit);
-static DEVICE_ATTR_RW(mem_used_max);
-static DEVICE_ATTR_RW(max_comp_streams);
-static DEVICE_ATTR_RW(comp_algorithm);
+	down_write(&zram->init_lock);
 
-static ssize_t io_stat_show(struct device *dev,
-		struct device_attribute *attr, char *buf)
+	zram->limit_pages = 0;
+
+	if (!init_done(zram)) {
+		up_write(&zram->init_lock);
+		return;
+	}
+
+	meta = zram->meta;
+	comp = zram->comp;
+	disksize = zram->disksize;
+	/*
+	 * Refcount will go down to 0 eventually and r/w handler
+	 * cannot handle further I/O so it will bail out by
+	 * check zram_meta_get.
+	 */
+	zram_meta_put(zram);
+	/*
+	 * We want to free zram_meta in process context to avoid
+	 * deadlock between reclaim path and any other locks.
+	 */
+	wait_event(zram->io_done, atomic_read(&zram->refcount) == 0);
+
+	/* Reset stats */
+	memset(&zram->stats, 0, sizeof(zram->stats));
+	zram->disksize = 0;
+	zram->max_comp_streams = 1;
+
+	set_capacity(zram->disk, 0);
+	part_stat_set_all(&zram->disk->part0, 0);
+
+	up_write(&zram->init_lock);
+	/* I/O operation under all of CPU are done so let's free */
+	zram_meta_free(meta, disksize);
+	zcomp_destroy(comp);
+}
+
+static ssize_t disksize_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t len)
 {
+	u64 disksize;
+	struct zcomp *comp;
+	struct zram_meta *meta;
 	struct zram *zram = dev_to_zram(dev);
-	ssize_t ret;
+	int err;
 
-	down_read(&zram->init_lock);
-	ret = scnprintf(buf, PAGE_SIZE,
-			"%8llu %8llu %8llu %8llu\n",
-			(u64)atomic64_read(&zram->stats.failed_reads),
-			(u64)atomic64_read(&zram->stats.failed_writes),
-			(u64)atomic64_read(&zram->stats.invalid_io),
-			(u64)atomic64_read(&zram->stats.notify_free));
-	up_read(&zram->init_lock);
+	disksize = memparse(buf, NULL);
+	if (!disksize)
+		return -EINVAL;
 
-	return ret;
+	disksize = PAGE_ALIGN(disksize);
+	meta = zram_meta_alloc(zram->disk->first_minor, disksize);
+	if (!meta)
+		return -ENOMEM;
+
+	comp = zcomp_create(zram->compressor, zram->max_comp_streams);
+	if (IS_ERR(comp)) {
+		pr_info("Cannot initialise %s compressing backend\n",
+				zram->compressor);
+		err = PTR_ERR(comp);
+		goto out_free_meta;
+	}
+
+	down_write(&zram->init_lock);
+	if (init_done(zram)) {
+		pr_info("Cannot change disksize for initialized device\n");
+		err = -EBUSY;
+		goto out_destroy_comp;
+	}
+
+	init_waitqueue_head(&zram->io_done);
+	atomic_set(&zram->refcount, 1);
+	zram->meta = meta;
+	zram->comp = comp;
+	zram->disksize = disksize;
+	set_capacity(zram->disk, zram->disksize >> SECTOR_SHIFT);
+	up_write(&zram->init_lock);
+
+	/*
+	 * Revalidate disk out of the init_lock to avoid lockdep splat.
+	 * It's okay because disk's capacity is protected by init_lock
+	 * so that revalidate_disk always sees up-to-date capacity.
+	 */
+	revalidate_disk(zram->disk);
+
+	return len;
+
+out_destroy_comp:
+	up_write(&zram->init_lock);
+	zcomp_destroy(comp);
+out_free_meta:
+	zram_meta_free(meta, disksize);
+	return err;
 }
 
-static ssize_t mm_stat_show(struct device *dev,
-		struct device_attribute *attr, char *buf)
+static ssize_t reset_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t len)
 {
-	struct zram *zram = dev_to_zram(dev);
-	u64 orig_size, mem_used = 0;
-	long max_used;
-	ssize_t ret;
+	int ret;
+	unsigned short do_reset;
+	struct zram *zram;
+	struct block_device *bdev;
 
-	down_read(&zram->init_lock);
-	if (init_done(zram))
-		mem_used = zs_get_total_pages(zram->meta->mem_pool);
+	ret = kstrtou16(buf, 10, &do_reset);
+	if (ret)
+		return ret;
 
-	orig_size = atomic64_read(&zram->stats.pages_stored);
-	max_used = atomic_long_read(&zram->stats.max_used_pages);
+	if (!do_reset)
+		return -EINVAL;
 
-	ret = scnprintf(buf, PAGE_SIZE,
-			"%8llu %8llu %8llu %8lu %8ld %8llu %8llu\n",
-			orig_size << PAGE_SHIFT,
-			(u64)atomic64_read(&zram->stats.compr_data_size),
-			mem_used << PAGE_SHIFT,
-			zram->limit_pages << PAGE_SHIFT,
-			max_used << PAGE_SHIFT,
-			(u64)atomic64_read(&zram->stats.zero_pages),
-			(u64)atomic64_read(&zram->stats.num_migrated));
-	up_read(&zram->init_lock);
+	zram = dev_to_zram(dev);
+	bdev = bdget_disk(zram->disk, 0);
+	if (!bdev)
+		return -ENOMEM;
+
+	mutex_lock(&bdev->bd_mutex);
+	/* Do not reset an active device or claimed device */
+	if (bdev->bd_openers || zram->claim) {
+		mutex_unlock(&bdev->bd_mutex);
+		bdput(bdev);
+		return -EBUSY;
+	}
+
+	/* From now on, anyone can't open /dev/zram[0-9] */
+	zram->claim = true;
+	mutex_unlock(&bdev->bd_mutex);
+
+	/* Make sure all the pending I/O are finished */
+	fsync_bdev(bdev);
+	zram_reset_device(zram);
+	revalidate_disk(zram->disk);
+	bdput(bdev);
+
+	mutex_lock(&bdev->bd_mutex);
+	zram->claim = false;
+	mutex_unlock(&bdev->bd_mutex);
+
+	return len;
+}
+
+static int zram_open(struct block_device *bdev, fmode_t mode)
+{
+	int ret = 0;
+	struct zram *zram;
+
+	WARN_ON(!mutex_is_locked(&bdev->bd_mutex));
+
+	zram = bdev->bd_disk->private_data;
+	/* zram was claimed to reset so open request fails */
+	if (zram->claim)
+		ret = -EBUSY;
 
 	return ret;
 }
 
-static DEVICE_ATTR_RO(io_stat);
-static DEVICE_ATTR_RO(mm_stat);
-ZRAM_ATTR_RO(num_reads);
-ZRAM_ATTR_RO(num_writes);
-ZRAM_ATTR_RO(failed_reads);
-ZRAM_ATTR_RO(failed_writes);
-ZRAM_ATTR_RO(invalid_io);
-ZRAM_ATTR_RO(notify_free);
-ZRAM_ATTR_RO(zero_pages);
-ZRAM_ATTR_RO(compr_data_size);
+static const struct block_device_operations zram_devops = {
+	.open = zram_open,
+	.swap_slot_free_notify = zram_slot_free_notify,
+	.rw_page = zram_rw_page,
+	.owner = THIS_MODULE
+};
+
+static DEVICE_ATTR_WO(compact);
+static DEVICE_ATTR_RW(disksize);
+static DEVICE_ATTR_RO(initstate);
+static DEVICE_ATTR_WO(reset);
+static DEVICE_ATTR_RO(orig_data_size);
+static DEVICE_ATTR_RO(mem_used_total);
+static DEVICE_ATTR_RW(mem_limit);
+static DEVICE_ATTR_RW(mem_used_max);
+static DEVICE_ATTR_RW(max_comp_streams);
+static DEVICE_ATTR_RW(comp_algorithm);
 
 static struct attribute *zram_disk_attrs[] = {
 	&dev_attr_disksize.attr,
@@ -1158,10 +1181,24 @@ static struct attribute_group zram_disk_attr_group = {
 	.attrs = zram_disk_attrs,
 };
 
-static int create_device(struct zram *zram, int device_id)
+/*
+ * Allocate and initialize new zram device. the function returns
+ * '>= 0' device_id upon success, and negative value otherwise.
+ */
+static int zram_add(void)
 {
+	struct zram *zram;
 	struct request_queue *queue;
-	int ret = -ENOMEM;
+	int ret, device_id;
+
+	zram = kzalloc(sizeof(struct zram), GFP_KERNEL);
+	if (!zram)
+		return -ENOMEM;
+
+	ret = idr_alloc(&zram_index_idr, zram, 0, 0, GFP_KERNEL);
+	if (ret < 0)
+		goto out_free_dev;
+	device_id = ret;
 
 	init_rwsem(&zram->init_lock);
 
@@ -1169,12 +1206,13 @@ static int create_device(struct zram *zram, int device_id)
 	if (!queue) {
 		pr_err("Error allocating disk queue for device %d\n",
 			device_id);
-		goto out;
+		ret = -ENOMEM;
+		goto out_free_idr;
 	}
 
 	blk_queue_make_request(queue, zram_make_request);
 
-	 /* gendisk structure */
+	/* gendisk structure */
 	zram->disk = alloc_disk(1);
 	if (!zram->disk) {
 		pr_warn("Error allocating disk structure for device %d\n",
@@ -1232,90 +1270,177 @@ static int create_device(struct zram *zram, int device_id)
 	strlcpy(zram->compressor, default_compressor, sizeof(zram->compressor));
 	zram->meta = NULL;
 	zram->max_comp_streams = 1;
-	return 0;
+
+	pr_info("Added device: %s\n", zram->disk->disk_name);
+	return device_id;
 
 out_free_disk:
 	del_gendisk(zram->disk);
 	put_disk(zram->disk);
 out_free_queue:
 	blk_cleanup_queue(queue);
-out:
+out_free_idr:
+	idr_remove(&zram_index_idr, device_id);
+out_free_dev:
+	kfree(zram);
 	return ret;
 }
 
-static void destroy_devices(unsigned int nr)
+static int zram_remove(struct zram *zram)
+{
+	struct block_device *bdev;
+
+	bdev = bdget_disk(zram->disk, 0);
+	if (!bdev)
+		return -ENOMEM;
+
+	mutex_lock(&bdev->bd_mutex);
+	if (bdev->bd_openers || zram->claim) {
+		mutex_unlock(&bdev->bd_mutex);
+		bdput(bdev);
+		return -EBUSY;
+	}
+
+	zram->claim = true;
+	mutex_unlock(&bdev->bd_mutex);
+
+	/*
+	 * Remove sysfs first, so no one will perform a disksize
+	 * store while we destroy the devices. This also helps during
+	 * hot_remove -- zram_reset_device() is the last holder of
+	 * ->init_lock, no later/concurrent disksize_store() or any
+	 * other sysfs handlers are possible.
+	 */
+	sysfs_remove_group(&disk_to_dev(zram->disk)->kobj,
+			&zram_disk_attr_group);
+
+	/* Make sure all the pending I/O are finished */
+	fsync_bdev(bdev);
+	zram_reset_device(zram);
+	bdput(bdev);
+
+	pr_info("Removed device: %s\n", zram->disk->disk_name);
+
+	idr_remove(&zram_index_idr, zram->disk->first_minor);
+	blk_cleanup_queue(zram->disk->queue);
+	del_gendisk(zram->disk);
+	put_disk(zram->disk);
+	kfree(zram);
+	return 0;
+}
+
+/* zram-control sysfs attributes */
+static ssize_t hot_add_show(struct class *class,
+			struct class_attribute *attr,
+			char *buf)
+{
+	int ret;
+
+	mutex_lock(&zram_index_mutex);
+	ret = zram_add();
+	mutex_unlock(&zram_index_mutex);
+
+	if (ret < 0)
+		return ret;
+	return scnprintf(buf, PAGE_SIZE, "%d\n", ret);
+}
+
+static ssize_t hot_remove_store(struct class *class,
+			struct class_attribute *attr,
+			const char *buf,
+			size_t count)
 {
 	struct zram *zram;
-	unsigned int i;
+	int ret, dev_id;
 
-	for (i = 0; i < nr; i++) {
-		zram = &zram_devices[i];
-		/*
-		 * Remove sysfs first, so no one will perform a disksize
-		 * store while we destroy the devices
-		 */
-		sysfs_remove_group(&disk_to_dev(zram->disk)->kobj,
-				&zram_disk_attr_group);
+	/* dev_id is gendisk->first_minor, which is `int' */
+	ret = kstrtoint(buf, 10, &dev_id);
+	if (ret)
+		return ret;
+	if (dev_id < 0)
+		return -EINVAL;
 
-		zram_reset_device(zram);
+	mutex_lock(&zram_index_mutex);
 
-		blk_cleanup_queue(zram->disk->queue);
-		del_gendisk(zram->disk);
-		put_disk(zram->disk);
-	}
+	zram = idr_find(&zram_index_idr, dev_id);
+	if (zram)
+		ret = zram_remove(zram);
+	else
+		ret = -ENODEV;
 
-	kfree(zram_devices);
+	mutex_unlock(&zram_index_mutex);
+	return ret ? ret : count;
+}
+
+static struct class_attribute zram_control_class_attrs[] = {
+	__ATTR_RO(hot_add),
+	__ATTR_WO(hot_remove),
+	__ATTR_NULL,
+};
+
+static struct class zram_control_class = {
+	.name		= "zram-control",
+	.owner		= THIS_MODULE,
+	.class_attrs	= zram_control_class_attrs,
+};
+
+static int zram_remove_cb(int id, void *ptr, void *data)
+{
+	zram_remove(ptr);
+	return 0;
+}
+
+static void destroy_devices(void)
+{
+	class_unregister(&zram_control_class);
+	idr_for_each(&zram_index_idr, &zram_remove_cb, NULL);
+	idr_destroy(&zram_index_idr);
 	unregister_blkdev(zram_major, "zram");
-	pr_info("Destroyed %u device(s)\n", nr);
 }
 
 static int __init zram_init(void)
 {
-	int ret, dev_id;
+	int ret;
 
-	if (num_devices > max_num_devices) {
-		pr_warn("Invalid value for num_devices: %u\n",
-				num_devices);
-		return -EINVAL;
+	ret = class_register(&zram_control_class);
+	if (ret) {
+		pr_warn("Unable to register zram-control class\n");
+		return ret;
 	}
 
 	zram_major = register_blkdev(0, "zram");
 	if (zram_major <= 0) {
 		pr_warn("Unable to get major number\n");
+		class_unregister(&zram_control_class);
 		return -EBUSY;
 	}
 
-	/* Allocate the device array and initialize each one */
-	zram_devices = kzalloc(num_devices * sizeof(struct zram), GFP_KERNEL);
-	if (!zram_devices) {
-		unregister_blkdev(zram_major, "zram");
-		return -ENOMEM;
-	}
-
-	for (dev_id = 0; dev_id < num_devices; dev_id++) {
-		ret = create_device(&zram_devices[dev_id], dev_id);
-		if (ret)
+	while (num_devices != 0) {
+		mutex_lock(&zram_index_mutex);
+		ret = zram_add();
+		mutex_unlock(&zram_index_mutex);
+		if (ret < 0)
 			goto out_error;
+		num_devices--;
 	}
 
-	pr_info("Created %u device(s)\n", num_devices);
 	return 0;
 
 out_error:
-	destroy_devices(dev_id);
+	destroy_devices();
 	return ret;
 }
 
 static void __exit zram_exit(void)
 {
-	destroy_devices(num_devices);
+	destroy_devices();
 }
 
 module_init(zram_init);
 module_exit(zram_exit);
 
 module_param(num_devices, uint, 0);
-MODULE_PARM_DESC(num_devices, "Number of zram devices");
+MODULE_PARM_DESC(num_devices, "Number of pre-created zram devices");
 
 MODULE_LICENSE("Dual BSD/GPL");
 MODULE_AUTHOR("Nitin Gupta <ngupta@vflare.org>");
diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
index 570c598f4ce9..6dbe2df506bf 100644
--- a/drivers/block/zram/zram_drv.h
+++ b/drivers/block/zram/zram_drv.h
@@ -20,12 +20,6 @@
 
 #include "zcomp.h"
 
-/*
- * Some arbitrary value. This is just to catch
- * invalid value for num_devices module parameter.
- */
-static const unsigned max_num_devices = 32;
-
 /*-- Configurable parameters */
 
 /*
@@ -121,5 +115,9 @@ struct zram {
 	 */
 	u64 disksize;	/* bytes */
 	char compressor[10];
+	/*
+	 * zram is claimed so open request will be failed
+	 */
+	bool claim; /* Protected by bdev->bd_mutex */
 };
 #endif
diff --git a/drivers/firmware/memmap.c b/drivers/firmware/memmap.c
index cc016c615c19..5de3ed29282c 100644
--- a/drivers/firmware/memmap.c
+++ b/drivers/firmware/memmap.c
@@ -144,7 +144,9 @@ static struct kobj_type __refdata memmap_ktype = {
  *
  * Common implementation of firmware_map_add() and firmware_map_add_early()
  * which expects a pre-allocated struct firmware_map_entry.
- **/
+ *
+ * Return: 0 always
+ */
 static int firmware_map_add_entry(u64 start, u64 end,
 				  const char *type,
 				  struct firmware_map_entry *entry)
@@ -170,7 +172,7 @@ static int firmware_map_add_entry(u64 start, u64 end,
  * @entry: removed entry.
  *
  * The caller must hold map_entries_lock, and release it properly.
- **/
+ */
 static inline void firmware_map_remove_entry(struct firmware_map_entry *entry)
 {
 	list_del(&entry->list);
@@ -208,7 +210,7 @@ static inline void remove_sysfs_fw_map_entry(struct firmware_map_entry *entry)
 	kobject_put(&entry->kobj);
 }
 
-/*
+/**
  * firmware_map_find_entry_in_list() - Search memmap entry in a given list.
  * @start: Start of the memory range.
  * @end:   End of the memory range (exclusive).
@@ -236,7 +238,7 @@ firmware_map_find_entry_in_list(u64 start, u64 end, const char *type,
 	return NULL;
 }
 
-/*
+/**
  * firmware_map_find_entry() - Search memmap entry in map_entries.
  * @start: Start of the memory range.
  * @end:   End of the memory range (exclusive).
@@ -254,7 +256,7 @@ firmware_map_find_entry(u64 start, u64 end, const char *type)
 	return firmware_map_find_entry_in_list(start, end, type, &map_entries);
 }
 
-/*
+/**
  * firmware_map_find_entry_bootmem() - Search memmap entry in map_entries_bootmem.
  * @start: Start of the memory range.
  * @end:   End of the memory range (exclusive).
@@ -283,8 +285,8 @@ firmware_map_find_entry_bootmem(u64 start, u64 end, const char *type)
  * similar to function firmware_map_add_early(). The only difference is that
  * it will create the syfs entry dynamically.
  *
- * Returns 0 on success, or -ENOMEM if no memory could be allocated.
- **/
+ * Return: 0 on success, or -ENOMEM if no memory could be allocated.
+ */
 int __meminit firmware_map_add_hotplug(u64 start, u64 end, const char *type)
 {
 	struct firmware_map_entry *entry;
@@ -325,8 +327,8 @@ int __meminit firmware_map_add_hotplug(u64 start, u64 end, const char *type)
  *
  * That function must be called before late_initcall.
  *
- * Returns 0 on success, or -ENOMEM if no memory could be allocated.
- **/
+ * Return: 0 on success, or -ENOMEM if no memory could be allocated.
+ */
 int __init firmware_map_add_early(u64 start, u64 end, const char *type)
 {
 	struct firmware_map_entry *entry;
@@ -346,8 +348,8 @@ int __init firmware_map_add_early(u64 start, u64 end, const char *type)
  *
  * removes a firmware mapping entry.
  *
- * Returns 0 on success, or -EINVAL if no entry.
- **/
+ * Return: 0 on success, or -EINVAL if no entry.
+ */
 int __meminit firmware_map_remove(u64 start, u64 end, const char *type)
 {
 	struct firmware_map_entry *entry;
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 4dbed4a67aaf..8d9f89b4519d 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -2024,7 +2024,6 @@ static int bind_rdev_to_array(struct md_rdev *rdev, struct mddev *mddev)
 {
 	char b[BDEVNAME_SIZE];
 	struct kobject *ko;
-	char *s;
 	int err;
 
 	/* prevent duplicates */
@@ -2070,8 +2069,7 @@ static int bind_rdev_to_array(struct md_rdev *rdev, struct mddev *mddev)
 		return -EBUSY;
 	}
 	bdevname(rdev->bdev,b);
-	while ( (s=strchr(b, '/')) != NULL)
-		*s = '!';
+	strreplace(b, '/', '!');
 
 	rdev->mddev = mddev;
 	printk(KERN_INFO "md: bind<%s>\n", b);
diff --git a/drivers/misc/altera-stapl/altera.c b/drivers/misc/altera-stapl/altera.c
index bca2630d006f..f53e217e963f 100644
--- a/drivers/misc/altera-stapl/altera.c
+++ b/drivers/misc/altera-stapl/altera.c
@@ -2451,7 +2451,7 @@ int altera_init(struct altera_config *config, const struct firmware *fw)
 
 	astate->config = config;
 	if (!astate->config->jtag_io) {
-		dprintk(KERN_INFO "%s: using byteblaster!\n", __func__);
+		dprintk("%s: using byteblaster!\n", __func__);
 		astate->config->jtag_io = netup_jtag_io_lpt;
 	}
 
diff --git a/drivers/misc/kgdbts.c b/drivers/misc/kgdbts.c
index 36f5d52775a9..9a60bd4d3c49 100644
--- a/drivers/misc/kgdbts.c
+++ b/drivers/misc/kgdbts.c
@@ -220,7 +220,7 @@ static unsigned long lookup_addr(char *arg)
 	else if (!strcmp(arg, "sys_open"))
 		addr = (unsigned long)do_sys_open;
 	else if (!strcmp(arg, "do_fork"))
-		addr = (unsigned long)do_fork;
+		addr = (unsigned long)_do_fork;
 	else if (!strcmp(arg, "hw_break_val"))
 		addr = (unsigned long)&hw_break_val;
 	addr = (unsigned long) dereference_function_descriptor((void *)addr);
diff --git a/drivers/misc/spear13xx_pcie_gadget.c b/drivers/misc/spear13xx_pcie_gadget.c
index fe3ad0ca9a3e..b8374cdaf9c9 100644
--- a/drivers/misc/spear13xx_pcie_gadget.c
+++ b/drivers/misc/spear13xx_pcie_gadget.c
@@ -2,7 +2,7 @@
  * drivers/misc/spear13xx_pcie_gadget.c
  *
  * Copyright (C) 2010 ST Microelectronics
- * Pratyush Anand<pratyush.anand@st.com>
+ * Pratyush Anand<pratyush.anand@gmail.com>
  *
  * This file is licensed under the terms of the GNU General Public
  * License version 2. This program is licensed "as is" without any
diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index 15731d1db918..97f3acd44798 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -79,6 +79,12 @@ static LIST_HEAD(target_list);
 /* This needs to be a spinlock because write_msg() cannot sleep */
 static DEFINE_SPINLOCK(target_list_lock);
 
+/*
+ * Console driver for extended netconsoles.  Registered on the first use to
+ * avoid unnecessarily enabling ext message formatting.
+ */
+static struct console netconsole_ext;
+
 /**
  * struct netconsole_target - Represents a configured netconsole target.
  * @list:	Links this target into the target_list.
@@ -104,14 +110,15 @@ struct netconsole_target {
 #ifdef	CONFIG_NETCONSOLE_DYNAMIC
 	struct config_item	item;
 #endif
-	int			enabled;
-	struct mutex		mutex;
+	bool			enabled;
+	bool			extended;
 	struct netpoll		np;
 };
 
 #ifdef	CONFIG_NETCONSOLE_DYNAMIC
 
 static struct configfs_subsystem netconsole_subsys;
+static DEFINE_MUTEX(dynamic_netconsole_mutex);
 
 static int __init dynamic_netconsole_init(void)
 {
@@ -185,9 +192,13 @@ static struct netconsole_target *alloc_param_target(char *target_config)
 	strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ);
 	nt->np.local_port = 6665;
 	nt->np.remote_port = 6666;
-	mutex_init(&nt->mutex);
 	eth_broadcast_addr(nt->np.remote_mac);
 
+	if (*target_config == '+') {
+		nt->extended = true;
+		target_config++;
+	}
+
 	/* Parse parameters and setup netpoll */
 	err = netpoll_parse_options(&nt->np, target_config);
 	if (err)
@@ -197,7 +208,7 @@ static struct netconsole_target *alloc_param_target(char *target_config)
 	if (err)
 		goto fail;
 
-	nt->enabled = 1;
+	nt->enabled = true;
 
 	return nt;
 
@@ -258,6 +269,11 @@ static ssize_t show_enabled(struct netconsole_target *nt, char *buf)
 	return snprintf(buf, PAGE_SIZE, "%d\n", nt->enabled);
 }
 
+static ssize_t show_extended(struct netconsole_target *nt, char *buf)
+{
+	return snprintf(buf, PAGE_SIZE, "%d\n", nt->extended);
+}
+
 static ssize_t show_dev_name(struct netconsole_target *nt, char *buf)
 {
 	return snprintf(buf, PAGE_SIZE, "%s\n", nt->np.dev_name);
@@ -322,13 +338,18 @@ static ssize_t store_enabled(struct netconsole_target *nt,
 		return err;
 	if (enabled < 0 || enabled > 1)
 		return -EINVAL;
-	if (enabled == nt->enabled) {
+	if ((bool)enabled == nt->enabled) {
 		pr_info("network logging has already %s\n",
 			nt->enabled ? "started" : "stopped");
 		return -EINVAL;
 	}
 
-	if (enabled) {	/* 1 */
+	if (enabled) {	/* true */
+		if (nt->extended && !(netconsole_ext.flags & CON_ENABLED)) {
+			netconsole_ext.flags |= CON_ENABLED;
+			register_console(&netconsole_ext);
+		}
+
 		/*
 		 * Skip netpoll_parse_options() -- all the attributes are
 		 * already configured via configfs. Just print them out.
@@ -340,13 +361,13 @@ static ssize_t store_enabled(struct netconsole_target *nt,
 			return err;
 
 		pr_info("netconsole: network logging started\n");
-	} else {	/* 0 */
+	} else {	/* false */
 		/* We need to disable the netconsole before cleaning it up
 		 * otherwise we might end up in write_msg() with
-		 * nt->np.dev == NULL and nt->enabled == 1
+		 * nt->np.dev == NULL and nt->enabled == true
 		 */
 		spin_lock_irqsave(&target_list_lock, flags);
-		nt->enabled = 0;
+		nt->enabled = false;
 		spin_unlock_irqrestore(&target_list_lock, flags);
 		netpoll_cleanup(&nt->np);
 	}
@@ -356,6 +377,30 @@ static ssize_t store_enabled(struct netconsole_target *nt,
 	return strnlen(buf, count);
 }
 
+static ssize_t store_extended(struct netconsole_target *nt,
+			      const char *buf,
+			      size_t count)
+{
+	int extended;
+	int err;
+
+	if (nt->enabled) {
+		pr_err("target (%s) is enabled, disable to update parameters\n",
+		       config_item_name(&nt->item));
+		return -EINVAL;
+	}
+
+	err = kstrtoint(buf, 10, &extended);
+	if (err < 0)
+		return err;
+	if (extended < 0 || extended > 1)
+		return -EINVAL;
+
+	nt->extended = extended;
+
+	return strnlen(buf, count);
+}
+
 static ssize_t store_dev_name(struct netconsole_target *nt,
 			      const char *buf,
 			      size_t count)
@@ -508,6 +553,7 @@ static struct netconsole_target_attr netconsole_target_##_name =	\
 	__CONFIGFS_ATTR(_name, S_IRUGO | S_IWUSR, show_##_name, store_##_name)
 
 NETCONSOLE_TARGET_ATTR_RW(enabled);
+NETCONSOLE_TARGET_ATTR_RW(extended);
 NETCONSOLE_TARGET_ATTR_RW(dev_name);
 NETCONSOLE_TARGET_ATTR_RW(local_port);
 NETCONSOLE_TARGET_ATTR_RW(remote_port);
@@ -518,6 +564,7 @@ NETCONSOLE_TARGET_ATTR_RW(remote_mac);
 
 static struct configfs_attribute *netconsole_target_attrs[] = {
 	&netconsole_target_enabled.attr,
+	&netconsole_target_extended.attr,
 	&netconsole_target_dev_name.attr,
 	&netconsole_target_local_port.attr,
 	&netconsole_target_remote_port.attr,
@@ -562,10 +609,10 @@ static ssize_t netconsole_target_attr_store(struct config_item *item,
 	struct netconsole_target_attr *na =
 		container_of(attr, struct netconsole_target_attr, attr);
 
-	mutex_lock(&nt->mutex);
+	mutex_lock(&dynamic_netconsole_mutex);
 	if (na->store)
 		ret = na->store(nt, buf, count);
-	mutex_unlock(&nt->mutex);
+	mutex_unlock(&dynamic_netconsole_mutex);
 
 	return ret;
 }
@@ -594,7 +641,7 @@ static struct config_item *make_netconsole_target(struct config_group *group,
 
 	/*
 	 * Allocate and initialize with defaults.
-	 * Target is disabled at creation (enabled == 0).
+	 * Target is disabled at creation (!enabled).
 	 */
 	nt = kzalloc(sizeof(*nt), GFP_KERNEL);
 	if (!nt)
@@ -604,7 +651,6 @@ static struct config_item *make_netconsole_target(struct config_group *group,
 	strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ);
 	nt->np.local_port = 6665;
 	nt->np.remote_port = 6666;
-	mutex_init(&nt->mutex);
 	eth_broadcast_addr(nt->np.remote_mac);
 
 	/* Initialize the config_item member */
@@ -695,7 +741,7 @@ restart:
 				spin_lock_irqsave(&target_list_lock, flags);
 				dev_put(nt->np.dev);
 				nt->np.dev = NULL;
-				nt->enabled = 0;
+				nt->enabled = false;
 				stopped = true;
 				netconsole_target_put(nt);
 				goto restart;
@@ -729,6 +775,82 @@ static struct notifier_block netconsole_netdev_notifier = {
 	.notifier_call  = netconsole_netdev_event,
 };
 
+/**
+ * send_ext_msg_udp - send extended log message to target
+ * @nt: target to send message to
+ * @msg: extended log message to send
+ * @msg_len: length of message
+ *
+ * Transfer extended log @msg to @nt.  If @msg is longer than
+ * MAX_PRINT_CHUNK, it'll be split and transmitted in multiple chunks with
+ * ncfrag header field added to identify them.
+ */
+static void send_ext_msg_udp(struct netconsole_target *nt, const char *msg,
+			     int msg_len)
+{
+	static char buf[MAX_PRINT_CHUNK]; /* protected by target_list_lock */
+	const char *header, *body;
+	int offset = 0;
+	int header_len, body_len;
+
+	if (msg_len <= MAX_PRINT_CHUNK) {
+		netpoll_send_udp(&nt->np, msg, msg_len);
+		return;
+	}
+
+	/* need to insert extra header fields, detect header and body */
+	header = msg;
+	body = memchr(msg, ';', msg_len);
+	if (WARN_ON_ONCE(!body))
+		return;
+
+	header_len = body - header;
+	body_len = msg_len - header_len - 1;
+	body++;
+
+	/*
+	 * Transfer multiple chunks with the following extra header.
+	 * "ncfrag=<byte-offset>/<total-bytes>"
+	 */
+	memcpy(buf, header, header_len);
+
+	while (offset < body_len) {
+		int this_header = header_len;
+		int this_chunk;
+
+		this_header += scnprintf(buf + this_header,
+					 sizeof(buf) - this_header,
+					 ",ncfrag=%d/%d;", offset, body_len);
+
+		this_chunk = min(body_len - offset,
+				 MAX_PRINT_CHUNK - this_header);
+		if (WARN_ON_ONCE(this_chunk <= 0))
+			return;
+
+		memcpy(buf + this_header, body + offset, this_chunk);
+
+		netpoll_send_udp(&nt->np, buf, this_header + this_chunk);
+
+		offset += this_chunk;
+	}
+}
+
+static void write_ext_msg(struct console *con, const char *msg,
+			  unsigned int len)
+{
+	struct netconsole_target *nt;
+	unsigned long flags;
+
+	if ((oops_only && !oops_in_progress) || list_empty(&target_list))
+		return;
+
+	spin_lock_irqsave(&target_list_lock, flags);
+	list_for_each_entry(nt, &target_list, list)
+		if (nt->extended && nt->enabled && netif_running(nt->np.dev))
+			send_ext_msg_udp(nt, msg, len);
+	spin_unlock_irqrestore(&target_list_lock, flags);
+}
+
 static void write_msg(struct console *con, const char *msg, unsigned int len)
 {
 	int frag, left;
@@ -744,8 +866,7 @@ static void write_msg(struct console *con, const char *msg, unsigned int len)
 
 	spin_lock_irqsave(&target_list_lock, flags);
 	list_for_each_entry(nt, &target_list, list) {
-		netconsole_target_get(nt);
-		if (nt->enabled && netif_running(nt->np.dev)) {
+		if (!nt->extended && nt->enabled && netif_running(nt->np.dev)) {
 			/*
 			 * We nest this inside the for-each-target loop above
 			 * so that we're able to get as much logging out to
@@ -760,11 +881,16 @@ static void write_msg(struct console *con, const char *msg, unsigned int len)
 				left -= frag;
 			}
 		}
-		netconsole_target_put(nt);
 	}
 	spin_unlock_irqrestore(&target_list_lock, flags);
 }
 
+static struct console netconsole_ext = {
+	.name	= "netcon_ext",
+	.flags	= CON_EXTENDED,	/* starts disabled, registered on first use */
+	.write	= write_ext_msg,
+};
+
 static struct console netconsole = {
 	.name	= "netcon",
 	.flags	= CON_ENABLED,
@@ -787,7 +913,11 @@ static int __init init_netconsole(void)
 				goto fail;
 			}
 			/* Dump existing printks when we register */
-			netconsole.flags |= CON_PRINTBUFFER;
+			if (nt->extended)
+				netconsole_ext.flags |= CON_PRINTBUFFER |
+							CON_ENABLED;
+			else
+				netconsole.flags |= CON_PRINTBUFFER;
 
 			spin_lock_irqsave(&target_list_lock, flags);
 			list_add(&nt->list, &target_list);
@@ -803,6 +933,8 @@ static int __init init_netconsole(void)
 	if (err)
 		goto undonotifier;
 
+	if (netconsole_ext.flags & CON_ENABLED)
+		register_console(&netconsole_ext);
 	register_console(&netconsole);
 	pr_info("network logging started\n");
 
@@ -831,6 +963,7 @@ static void __exit cleanup_netconsole(void)
 {
 	struct netconsole_target *nt, *tmp;
 
+	unregister_console(&netconsole_ext);
 	unregister_console(&netconsole);
 	dynamic_netconsole_exit();
 	unregister_netdevice_notifier(&netconsole_netdev_notifier);
diff --git a/drivers/pci/host/pcie-spear13xx.c b/drivers/pci/host/pcie-spear13xx.c
index dfec4281bd50..c49fbdc0f6e4 100644
--- a/drivers/pci/host/pcie-spear13xx.c
+++ b/drivers/pci/host/pcie-spear13xx.c
@@ -4,8 +4,8 @@
  * SPEAr13xx PCIe Glue Layer Source Code
  *
  * Copyright (C) 2010-2014 ST Microelectronics
- * Pratyush Anand <pratyush.anand@st.com>
- * Mohit Kumar <mohit.kumar@st.com>
+ * Pratyush Anand <pratyush.anand@gmail.com>
+ * Mohit Kumar <mohit.kumar.dhaka@gmail.com>
  *
  * This file is licensed under the terms of the GNU General Public
  * License version 2. This program is licensed "as is" without any
@@ -386,5 +386,5 @@ static int __init spear13xx_pcie_init(void)
 module_init(spear13xx_pcie_init);
 
 MODULE_DESCRIPTION("ST Microelectronics SPEAr13xx PCIe host controller driver");
-MODULE_AUTHOR("Pratyush Anand <pratyush.anand@st.com>");
+MODULE_AUTHOR("Pratyush Anand <pratyush.anand@gmail.com>");
 MODULE_LICENSE("GPL v2");
diff --git a/drivers/phy/phy-spear1310-miphy.c b/drivers/phy/phy-spear1310-miphy.c
index 65ae640cfbd1..45d0005b2203 100644
--- a/drivers/phy/phy-spear1310-miphy.c
+++ b/drivers/phy/phy-spear1310-miphy.c
@@ -2,8 +2,8 @@
  * ST SPEAr1310-miphy driver
  *
  * Copyright (C) 2014 ST Microelectronics
- * Pratyush Anand <pratyush.anand@st.com>
- * Mohit Kumar <mohit.kumar@st.com>
+ * Pratyush Anand <pratyush.anand@gmail.com>
+ * Mohit Kumar <mohit.kumar.dhaka@gmail.com>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
@@ -257,5 +257,5 @@ static struct platform_driver spear1310_miphy_driver = {
 module_platform_driver(spear1310_miphy_driver);
 
 MODULE_DESCRIPTION("ST SPEAR1310-MIPHY driver");
-MODULE_AUTHOR("Pratyush Anand <pratyush.anand@st.com>");
+MODULE_AUTHOR("Pratyush Anand <pratyush.anand@gmail.com>");
 MODULE_LICENSE("GPL v2");
diff --git a/drivers/phy/phy-spear1340-miphy.c b/drivers/phy/phy-spear1340-miphy.c
index 1a00c2817f34..494240da4a39 100644
--- a/drivers/phy/phy-spear1340-miphy.c
+++ b/drivers/phy/phy-spear1340-miphy.c
@@ -2,8 +2,8 @@
  * ST spear1340-miphy driver
  *
  * Copyright (C) 2014 ST Microelectronics
- * Pratyush Anand <pratyush.anand@st.com>
- * Mohit Kumar <mohit.kumar@st.com>
+ * Pratyush Anand <pratyush.anand@gmail.com>
+ * Mohit Kumar <mohit.kumar.dhaka@gmail.com>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
@@ -290,5 +290,5 @@ static struct platform_driver spear1340_miphy_driver = {
 module_platform_driver(spear1340_miphy_driver);
 
 MODULE_DESCRIPTION("ST SPEAR1340-MIPHY driver");
-MODULE_AUTHOR("Pratyush Anand <pratyush.anand@st.com>");
+MODULE_AUTHOR("Pratyush Anand <pratyush.anand@gmail.com>");
 MODULE_LICENSE("GPL v2");
diff --git a/drivers/usb/misc/lvstest.c b/drivers/usb/misc/lvstest.c
index 62cb8cd08403..86b4e4b2ab9a 100644
--- a/drivers/usb/misc/lvstest.c
+++ b/drivers/usb/misc/lvstest.c
@@ -4,7 +4,7 @@
  * Test pattern generation for Link Layer Validation System Tests
  *
  * Copyright (C) 2014 ST Microelectronics
- * Pratyush Anand <pratyush.anand@st.com>
+ * Pratyush Anand <pratyush.anand@gmail.com>
  *
  * This file is licensed under the terms of the GNU General Public
  * License version 2. This program is licensed "as is" without any