Merge branch 'for-4.14/block' of git://git.kernel.dk/linux-block

Pull block layer updates from Jens Axboe:
 "This is the first pull request for 4.14, containing most of the code
  changes. It's a quiet series this round, which I think we needed after
  the churn of the last few series. This contains:

   - Fix for a registration race in loop, from Anton Volkov.

   - Overflow complaint fix from Arnd for DAC960.

   - Series of drbd changes from the usual suspects.

   - Conversion of the stec/skd driver to blk-mq. From Bart.

   - A few BFQ improvements/fixes from Paolo.

   - CFQ improvement from Ritesh, allowing idling for group idle.

   - A few fixes found by Dan's smatch, courtesy of Dan.

   - A warning fixup for a race between changing the IO scheduler and
     device remova. From David Jeffery.

   - A few nbd fixes from Josef.

   - Support for cgroup info in blktrace, from Shaohua.

   - Also from Shaohua, new features in the null_blk driver to allow it
     to actually hold data, among other things.

   - Various corner cases and error handling fixes from Weiping Zhang.

   - Improvements to the IO stats tracking for blk-mq from me. Can
     drastically improve performance for fast devices and/or big
     machines.

   - Series from Christoph removing bi_bdev as being needed for IO
     submission, in preparation for nvme multipathing code.

   - Series from Bart, including various cleanups and fixes for switch
     fall through case complaints"

* 'for-4.14/block' of git://git.kernel.dk/linux-block: (162 commits)
  kernfs: checking for IS_ERR() instead of NULL
  drbd: remove BIOSET_NEED_RESCUER flag from drbd_{md_,}io_bio_set
  drbd: Fix allyesconfig build, fix recent commit
  drbd: switch from kmalloc() to kmalloc_array()
  drbd: abort drbd_start_resync if there is no connection
  drbd: move global variables to drbd namespace and make some static
  drbd: rename "usermode_helper" to "drbd_usermode_helper"
  drbd: fix race between handshake and admin disconnect/down
  drbd: fix potential deadlock when trying to detach during handshake
  drbd: A single dot should be put into a sequence.
  drbd: fix rmmod cleanup, remove _all_ debugfs entries
  drbd: Use setup_timer() instead of init_timer() to simplify the code.
  drbd: fix potential get_ldev/put_ldev refcount imbalance during attach
  drbd: new disk-option disable-write-same
  drbd: Fix resource role for newly created resources in events2
  drbd: mark symbols static where possible
  drbd: Send P_NEG_ACK upon write error in protocol != C
  drbd: add explicit plugging when submitting batches
  drbd: change list_for_each_safe to while(list_first_entry_or_null)
  drbd: introduce drbd_recv_header_maybe_unplug
  ...

28 files changed, 2404 insertions, 2672 deletions

diff --git a/drivers/block/DAC960.c b/drivers/block/DAC960.c
index 245a879b036e..255591ab3716 100644
--- a/drivers/block/DAC960.c
+++ b/drivers/block/DAC960.c
@@ -1678,9 +1678,12 @@ static bool DAC960_V1_ReadControllerConfiguration(DAC960_Controller_T
       Enquiry2->FirmwareID.FirmwareType = '0';
       Enquiry2->FirmwareID.TurnID = 0;
     }
-  sprintf(Controller->FirmwareVersion, "%d.%02d-%c-%02d",
-	  Enquiry2->FirmwareID.MajorVersion, Enquiry2->FirmwareID.MinorVersion,
-	  Enquiry2->FirmwareID.FirmwareType, Enquiry2->FirmwareID.TurnID);
+  snprintf(Controller->FirmwareVersion, sizeof(Controller->FirmwareVersion),
+	   "%d.%02d-%c-%02d",
+	   Enquiry2->FirmwareID.MajorVersion,
+	   Enquiry2->FirmwareID.MinorVersion,
+	   Enquiry2->FirmwareID.FirmwareType,
+	   Enquiry2->FirmwareID.TurnID);
   if (!((Controller->FirmwareVersion[0] == '5' &&
 	 strcmp(Controller->FirmwareVersion, "5.06") >= 0) ||
 	(Controller->FirmwareVersion[0] == '4' &&
@@ -6588,7 +6591,8 @@ static void DAC960_CreateProcEntries(DAC960_Controller_T *Controller)
 			    &dac960_proc_fops);
 	}
 
-	sprintf(Controller->ControllerName, "c%d", Controller->ControllerNumber);
+	snprintf(Controller->ControllerName, sizeof(Controller->ControllerName),
+		 "c%d", Controller->ControllerNumber);
 	ControllerProcEntry = proc_mkdir(Controller->ControllerName,
 					 DAC960_ProcDirectoryEntry);
 	proc_create_data("initial_status", 0, ControllerProcEntry, &dac960_initial_status_proc_fops, Controller);
diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
index 80aaf3420e12..104180e3c55e 100644
--- a/drivers/block/Kconfig
+++ b/drivers/block/Kconfig
@@ -17,6 +17,7 @@ if BLK_DEV
 
 config BLK_DEV_NULL_BLK
 	tristate "Null test block driver"
+	depends on CONFIGFS_FS
 
 config BLK_DEV_FD
 	tristate "Normal floppy disk support"
diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index 5d9ed0616413..bbd0d186cfc0 100644
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -294,14 +294,13 @@ out:
 
 static blk_qc_t brd_make_request(struct request_queue *q, struct bio *bio)
 {
-	struct block_device *bdev = bio->bi_bdev;
-	struct brd_device *brd = bdev->bd_disk->private_data;
+	struct brd_device *brd = bio->bi_disk->private_data;
 	struct bio_vec bvec;
 	sector_t sector;
 	struct bvec_iter iter;
 
 	sector = bio->bi_iter.bi_sector;
-	if (bio_end_sector(bio) > get_capacity(bdev->bd_disk))
+	if (bio_end_sector(bio) > get_capacity(bio->bi_disk))
 		goto io_error;
 
 	bio_for_each_segment(bvec, bio, iter) {
diff --git a/drivers/block/drbd/drbd_actlog.c b/drivers/block/drbd/drbd_actlog.c
index e02c45cd3c5a..5f0eaee8c8a7 100644
--- a/drivers/block/drbd/drbd_actlog.c
+++ b/drivers/block/drbd/drbd_actlog.c
@@ -151,7 +151,7 @@ static int _drbd_md_sync_page_io(struct drbd_device *device,
 	op_flags |= REQ_SYNC;
 
 	bio = bio_alloc_drbd(GFP_NOIO);
-	bio->bi_bdev = bdev->md_bdev;
+	bio_set_dev(bio, bdev->md_bdev);
 	bio->bi_iter.bi_sector = sector;
 	err = -EIO;
 	if (bio_add_page(bio, device->md_io.page, size, 0) != size)
diff --git a/drivers/block/drbd/drbd_bitmap.c b/drivers/block/drbd/drbd_bitmap.c
index 809fd245c3dc..bd97908c766f 100644
--- a/drivers/block/drbd/drbd_bitmap.c
+++ b/drivers/block/drbd/drbd_bitmap.c
@@ -1019,7 +1019,7 @@ static void bm_page_io_async(struct drbd_bm_aio_ctx *ctx, int page_nr) __must_ho
 		bm_store_page_idx(page, page_nr);
 	} else
 		page = b->bm_pages[page_nr];
-	bio->bi_bdev = device->ldev->md_bdev;
+	bio_set_dev(bio, device->ldev->md_bdev);
 	bio->bi_iter.bi_sector = on_disk_sector;
 	/* bio_add_page of a single page to an empty bio will always succeed,
 	 * according to api.  Do we want to assert that? */
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index d17b6e6393c7..7e8589ce631c 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -63,19 +63,15 @@
 # define __must_hold(x)
 #endif
 
-/* module parameter, defined in drbd_main.c */
-extern unsigned int minor_count;
-extern bool disable_sendpage;
-extern bool allow_oos;
-void tl_abort_disk_io(struct drbd_device *device);
-
+/* shared module parameters, defined in drbd_main.c */
 #ifdef CONFIG_DRBD_FAULT_INJECTION
-extern int enable_faults;
-extern int fault_rate;
-extern int fault_devs;
+extern int drbd_enable_faults;
+extern int drbd_fault_rate;
 #endif
 
-extern char usermode_helper[];
+extern unsigned int drbd_minor_count;
+extern char drbd_usermode_helper[];
+extern int drbd_proc_details;
 
 
 /* This is used to stop/restart our threads.
@@ -181,8 +177,8 @@ _drbd_insert_fault(struct drbd_device *device, unsigned int type);
 static inline int
 drbd_insert_fault(struct drbd_device *device, unsigned int type) {
 #ifdef CONFIG_DRBD_FAULT_INJECTION
-	return fault_rate &&
-		(enable_faults & (1<<type)) &&
+	return drbd_fault_rate &&
+		(drbd_enable_faults & (1<<type)) &&
 		_drbd_insert_fault(device, type);
 #else
 	return 0;
@@ -745,6 +741,8 @@ struct drbd_connection {
 	unsigned current_tle_writes;	/* writes seen within this tl epoch */
 
 	unsigned long last_reconnect_jif;
+	/* empty member on older kernels without blk_start_plug() */
+	struct blk_plug receiver_plug;
 	struct drbd_thread receiver;
 	struct drbd_thread worker;
 	struct drbd_thread ack_receiver;
@@ -1131,7 +1129,8 @@ extern void conn_send_sr_reply(struct drbd_connection *connection, enum drbd_sta
 extern int drbd_send_rs_deallocated(struct drbd_peer_device *, struct drbd_peer_request *);
 extern void drbd_backing_dev_free(struct drbd_device *device, struct drbd_backing_dev *ldev);
 extern void drbd_device_cleanup(struct drbd_device *device);
-void drbd_print_uuids(struct drbd_device *device, const char *text);
+extern void drbd_print_uuids(struct drbd_device *device, const char *text);
+extern void drbd_queue_unplug(struct drbd_device *device);
 
 extern void conn_md_sync(struct drbd_connection *connection);
 extern void drbd_md_write(struct drbd_device *device, void *buffer);
@@ -1463,8 +1462,6 @@ extern struct drbd_resource *drbd_find_resource(const char *name);
 extern void drbd_destroy_resource(struct kref *kref);
 extern void conn_free_crypto(struct drbd_connection *connection);
 
-extern int proc_details;
-
 /* drbd_req */
 extern void do_submit(struct work_struct *ws);
 extern void __drbd_make_request(struct drbd_device *, struct bio *, unsigned long);
@@ -1628,8 +1625,8 @@ static inline void drbd_generic_make_request(struct drbd_device *device,
 					     int fault_type, struct bio *bio)
 {
 	__release(local);
-	if (!bio->bi_bdev) {
-		drbd_err(device, "drbd_generic_make_request: bio->bi_bdev == NULL\n");
+	if (!bio->bi_disk) {
+		drbd_err(device, "drbd_generic_make_request: bio->bi_disk == NULL\n");
 		bio->bi_status = BLK_STS_IOERR;
 		bio_endio(bio);
 		return;
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index e2ed28d45ce1..8cb3791898ae 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -77,41 +77,41 @@ MODULE_PARM_DESC(minor_count, "Approximate number of drbd devices ("
 MODULE_ALIAS_BLOCKDEV_MAJOR(DRBD_MAJOR);
 
 #include <linux/moduleparam.h>
-/* allow_open_on_secondary */
-MODULE_PARM_DESC(allow_oos, "DONT USE!");
 /* thanks to these macros, if compiled into the kernel (not-module),
- * this becomes the boot parameter drbd.minor_count */
-module_param(minor_count, uint, 0444);
-module_param(disable_sendpage, bool, 0644);
-module_param(allow_oos, bool, 0);
-module_param(proc_details, int, 0644);
+ * these become boot parameters (e.g., drbd.minor_count) */
 
 #ifdef CONFIG_DRBD_FAULT_INJECTION
-int enable_faults;
-int fault_rate;
-static int fault_count;
-int fault_devs;
+int drbd_enable_faults;
+int drbd_fault_rate;
+static int drbd_fault_count;
+static int drbd_fault_devs;
 /* bitmap of enabled faults */
-module_param(enable_faults, int, 0664);
+module_param_named(enable_faults, drbd_enable_faults, int, 0664);
 /* fault rate % value - applies to all enabled faults */
-module_param(fault_rate, int, 0664);
+module_param_named(fault_rate, drbd_fault_rate, int, 0664);
 /* count of faults inserted */
-module_param(fault_count, int, 0664);
+module_param_named(fault_count, drbd_fault_count, int, 0664);
 /* bitmap of devices to insert faults on */
-module_param(fault_devs, int, 0644);
+module_param_named(fault_devs, drbd_fault_devs, int, 0644);
 #endif
 
-/* module parameter, defined */
-unsigned int minor_count = DRBD_MINOR_COUNT_DEF;
-bool disable_sendpage;
-bool allow_oos;
-int proc_details;       /* Detail level in proc drbd*/
-
+/* module parameters we can keep static */
+static bool drbd_allow_oos; /* allow_open_on_secondary */
+static bool drbd_disable_sendpage;
+MODULE_PARM_DESC(allow_oos, "DONT USE!");
+module_param_named(allow_oos, drbd_allow_oos, bool, 0);
+module_param_named(disable_sendpage, drbd_disable_sendpage, bool, 0644);
+
+/* module parameters we share */
+int drbd_proc_details; /* Detail level in proc drbd*/
+module_param_named(proc_details, drbd_proc_details, int, 0644);
+/* module parameters shared with defaults */
+unsigned int drbd_minor_count = DRBD_MINOR_COUNT_DEF;
 /* Module parameter for setting the user mode helper program
  * to run. Default is /sbin/drbdadm */
-char usermode_helper[80] = "/sbin/drbdadm";
-
-module_param_string(usermode_helper, usermode_helper, sizeof(usermode_helper), 0644);
+char drbd_usermode_helper[80] = "/sbin/drbdadm";
+module_param_named(minor_count, drbd_minor_count, uint, 0444);
+module_param_string(usermode_helper, drbd_usermode_helper, sizeof(drbd_usermode_helper), 0644);
 
 /* in 2.6.x, our device mapping and config info contains our virtual gendisks
  * as member "struct gendisk *vdisk;"
@@ -923,7 +923,9 @@ void drbd_gen_and_send_sync_uuid(struct drbd_peer_device *peer_device)
 }
 
 /* communicated if (agreed_features & DRBD_FF_WSAME) */
-void assign_p_sizes_qlim(struct drbd_device *device, struct p_sizes *p, struct request_queue *q)
+static void
+assign_p_sizes_qlim(struct drbd_device *device, struct p_sizes *p,
+					struct request_queue *q)
 {
 	if (q) {
 		p->qlim->physical_block_size = cpu_to_be32(queue_physical_block_size(q));
@@ -1560,7 +1562,7 @@ static int _drbd_send_page(struct drbd_peer_device *peer_device, struct page *pa
 	 * put_page(); and would cause either a VM_BUG directly, or
 	 * __page_cache_release a page that would actually still be referenced
 	 * by someone, leading to some obscure delayed Oops somewhere else. */
-	if (disable_sendpage || (page_count(page) < 1) || PageSlab(page))
+	if (drbd_disable_sendpage || (page_count(page) < 1) || PageSlab(page))
 		return _drbd_no_send_page(peer_device, page, offset, size, msg_flags);
 
 	msg_flags |= MSG_NOSIGNAL;
@@ -1932,7 +1934,7 @@ static int drbd_open(struct block_device *bdev, fmode_t mode)
 	if (device->state.role != R_PRIMARY) {
 		if (mode & FMODE_WRITE)
 			rv = -EROFS;
-		else if (!allow_oos)
+		else if (!drbd_allow_oos)
 			rv = -EMEDIUMTYPE;
 	}
 
@@ -1952,6 +1954,19 @@ static void drbd_release(struct gendisk *gd, fmode_t mode)
 	mutex_unlock(&drbd_main_mutex);
 }
 
+/* need to hold resource->req_lock */
+void drbd_queue_unplug(struct drbd_device *device)
+{
+	if (device->state.pdsk >= D_INCONSISTENT && device->state.conn >= C_CONNECTED) {
+		D_ASSERT(device, device->state.role == R_PRIMARY);
+		if (test_and_clear_bit(UNPLUG_REMOTE, &device->flags)) {
+			drbd_queue_work_if_unqueued(
+				&first_peer_device(device)->connection->sender_work,
+				&device->unplug_work);
+		}
+	}
+}
+
 static void drbd_set_defaults(struct drbd_device *device)
 {
 	/* Beware! The actual layout differs
@@ -2008,18 +2023,14 @@ void drbd_init_set_defaults(struct drbd_device *device)
 	device->unplug_work.cb  = w_send_write_hint;
 	device->bm_io_work.w.cb = w_bitmap_io;
 
-	init_timer(&device->resync_timer);
-	init_timer(&device->md_sync_timer);
-	init_timer(&device->start_resync_timer);
-	init_timer(&device->request_timer);
-	device->resync_timer.function = resync_timer_fn;
-	device->resync_timer.data = (unsigned long) device;
-	device->md_sync_timer.function = md_sync_timer_fn;
-	device->md_sync_timer.data = (unsigned long) device;
-	device->start_resync_timer.function = start_resync_timer_fn;
-	device->start_resync_timer.data = (unsigned long) device;
-	device->request_timer.function = request_timer_fn;
-	device->request_timer.data = (unsigned long) device;
+	setup_timer(&device->resync_timer, resync_timer_fn,
+			(unsigned long)device);
+	setup_timer(&device->md_sync_timer, md_sync_timer_fn,
+			(unsigned long)device);
+	setup_timer(&device->start_resync_timer, start_resync_timer_fn,
+			(unsigned long)device);
+	setup_timer(&device->request_timer, request_timer_fn,
+			(unsigned long)device);
 
 	init_waitqueue_head(&device->misc_wait);
 	init_waitqueue_head(&device->state_wait);
@@ -2131,7 +2142,7 @@ static void drbd_destroy_mempools(void)
 static int drbd_create_mempools(void)
 {
 	struct page *page;
-	const int number = (DRBD_MAX_BIO_SIZE/PAGE_SIZE) * minor_count;
+	const int number = (DRBD_MAX_BIO_SIZE/PAGE_SIZE) * drbd_minor_count;
 	int i;
 
 	/* prepare our caches and mempools */
@@ -2167,13 +2178,12 @@ static int drbd_create_mempools(void)
 		goto Enomem;
 
 	/* mempools */
-	drbd_io_bio_set = bioset_create(BIO_POOL_SIZE, 0, BIOSET_NEED_RESCUER);
+	drbd_io_bio_set = bioset_create(BIO_POOL_SIZE, 0, 0);
 	if (drbd_io_bio_set == NULL)
 		goto Enomem;
 
 	drbd_md_io_bio_set = bioset_create(DRBD_MIN_POOL_PAGES, 0,
-					   BIOSET_NEED_BVECS |
-					   BIOSET_NEED_RESCUER);
+					   BIOSET_NEED_BVECS);
 	if (drbd_md_io_bio_set == NULL)
 		goto Enomem;
 
@@ -2409,7 +2419,6 @@ static void drbd_cleanup(void)
 		destroy_workqueue(retry.wq);
 
 	drbd_genl_unregister();
-	drbd_debugfs_cleanup();
 
 	idr_for_each_entry(&drbd_devices, device, i)
 		drbd_delete_device(device);
@@ -2420,6 +2429,8 @@ static void drbd_cleanup(void)
 		drbd_free_resource(resource);
 	}
 
+	drbd_debugfs_cleanup();
+
 	drbd_destroy_mempools();
 	unregister_blkdev(DRBD_MAJOR, "drbd");
 
@@ -2972,12 +2983,12 @@ static int __init drbd_init(void)
 {
 	int err;
 
-	if (minor_count < DRBD_MINOR_COUNT_MIN || minor_count > DRBD_MINOR_COUNT_MAX) {
-		pr_err("invalid minor_count (%d)\n", minor_count);
+	if (drbd_minor_count < DRBD_MINOR_COUNT_MIN || drbd_minor_count > DRBD_MINOR_COUNT_MAX) {
+		pr_err("invalid minor_count (%d)\n", drbd_minor_count);
 #ifdef MODULE
 		return -EINVAL;
 #else
-		minor_count = DRBD_MINOR_COUNT_DEF;
+		drbd_minor_count = DRBD_MINOR_COUNT_DEF;
 #endif
 	}
 
@@ -3900,12 +3911,12 @@ _drbd_insert_fault(struct drbd_device *device, unsigned int type)
 	static struct fault_random_state rrs = {0, 0};
 
 	unsigned int ret = (
-		(fault_devs == 0 ||
-			((1 << device_to_minor(device)) & fault_devs) != 0) &&
-		(((_drbd_fault_random(&rrs) % 100) + 1) <= fault_rate));
+		(drbd_fault_devs == 0 ||
+			((1 << device_to_minor(device)) & drbd_fault_devs) != 0) &&
+		(((_drbd_fault_random(&rrs) % 100) + 1) <= drbd_fault_rate));
 
 	if (ret) {
-		fault_count++;
+		drbd_fault_count++;
 
 		if (__ratelimit(&drbd_ratelimit_state))
 			drbd_warn(device, "***Simulating %s failure\n",
diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index ad0fcb43e45c..a12f77e6891e 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -344,7 +344,7 @@ int drbd_khelper(struct drbd_device *device, char *cmd)
 			 (char[60]) { }, /* address */
 			NULL };
 	char mb[14];
-	char *argv[] = {usermode_helper, cmd, mb, NULL };
+	char *argv[] = {drbd_usermode_helper, cmd, mb, NULL };
 	struct drbd_connection *connection = first_peer_device(device)->connection;
 	struct sib_info sib;
 	int ret;
@@ -359,19 +359,19 @@ int drbd_khelper(struct drbd_device *device, char *cmd)
 	 * write out any unsynced meta data changes now */
 	drbd_md_sync(device);
 
-	drbd_info(device, "helper command: %s %s %s\n", usermode_helper, cmd, mb);
+	drbd_info(device, "helper command: %s %s %s\n", drbd_usermode_helper, cmd, mb);
 	sib.sib_reason = SIB_HELPER_PRE;
 	sib.helper_name = cmd;
 	drbd_bcast_event(device, &sib);
 	notify_helper(NOTIFY_CALL, device, connection, cmd, 0);
-	ret = call_usermodehelper(usermode_helper, argv, envp, UMH_WAIT_PROC);
+	ret = call_usermodehelper(drbd_usermode_helper, argv, envp, UMH_WAIT_PROC);
 	if (ret)
 		drbd_warn(device, "helper command: %s %s %s exit code %u (0x%x)\n",
-				usermode_helper, cmd, mb,
+				drbd_usermode_helper, cmd, mb,
 				(ret >> 8) & 0xff, ret);
 	else
 		drbd_info(device, "helper command: %s %s %s exit code %u (0x%x)\n",
-				usermode_helper, cmd, mb,
+				drbd_usermode_helper, cmd, mb,
 				(ret >> 8) & 0xff, ret);
 	sib.sib_reason = SIB_HELPER_POST;
 	sib.helper_exit_code = ret;
@@ -396,24 +396,24 @@ enum drbd_peer_state conn_khelper(struct drbd_connection *connection, char *cmd)
 			 (char[60]) { }, /* address */
 			NULL };
 	char *resource_name = connection->resource->name;
-	char *argv[] = {usermode_helper, cmd, resource_name, NULL };
+	char *argv[] = {drbd_usermode_helper, cmd, resource_name, NULL };
 	int ret;
 
 	setup_khelper_env(connection, envp);
 	conn_md_sync(connection);
 
-	drbd_info(connection, "helper command: %s %s %s\n", usermode_helper, cmd, resource_name);
+	drbd_info(connection, "helper command: %s %s %s\n", drbd_usermode_helper, cmd, resource_name);
 	/* TODO: conn_bcast_event() ?? */
 	notify_helper(NOTIFY_CALL, NULL, connection, cmd, 0);
 
-	ret = call_usermodehelper(usermode_helper, argv, envp, UMH_WAIT_PROC);
+	ret = call_usermodehelper(drbd_usermode_helper, argv, envp, UMH_WAIT_PROC);
 	if (ret)
 		drbd_warn(connection, "helper command: %s %s %s exit code %u (0x%x)\n",
-			  usermode_helper, cmd, resource_name,
+			  drbd_usermode_helper, cmd, resource_name,
 			  (ret >> 8) & 0xff, ret);
 	else
 		drbd_info(connection, "helper command: %s %s %s exit code %u (0x%x)\n",
-			  usermode_helper, cmd, resource_name,
+			  drbd_usermode_helper, cmd, resource_name,
 			  (ret >> 8) & 0xff, ret);
 	/* TODO: conn_bcast_event() ?? */
 	notify_helper(NOTIFY_RESPONSE, NULL, connection, cmd, ret);
@@ -1236,12 +1236,18 @@ static void fixup_discard_if_not_supported(struct request_queue *q)
 
 static void decide_on_write_same_support(struct drbd_device *device,
 			struct request_queue *q,
-			struct request_queue *b, struct o_qlim *o)
+			struct request_queue *b, struct o_qlim *o,
+			bool disable_write_same)
 {
 	struct drbd_peer_device *peer_device = first_peer_device(device);
 	struct drbd_connection *connection = peer_device->connection;
 	bool can_do = b ? b->limits.max_write_same_sectors : true;
 
+	if (can_do && disable_write_same) {
+		can_do = false;
+		drbd_info(peer_device, "WRITE_SAME disabled by config\n");
+	}
+
 	if (can_do && connection->cstate >= C_CONNECTED && !(connection->agreed_features & DRBD_FF_WSAME)) {
 		can_do = false;
 		drbd_info(peer_device, "peer does not support WRITE_SAME\n");
@@ -1302,6 +1308,7 @@ static void drbd_setup_queue_param(struct drbd_device *device, struct drbd_backi
 	struct request_queue *b = NULL;
 	struct disk_conf *dc;
 	bool discard_zeroes_if_aligned = true;
+	bool disable_write_same = false;
 
 	if (bdev) {
 		b = bdev->backing_bdev->bd_disk->queue;
@@ -1311,6 +1318,7 @@ static void drbd_setup_queue_param(struct drbd_device *device, struct drbd_backi
 		dc = rcu_dereference(device->ldev->disk_conf);
 		max_segments = dc->max_bio_bvecs;
 		discard_zeroes_if_aligned = dc->discard_zeroes_if_aligned;
+		disable_write_same = dc->disable_write_same;
 		rcu_read_unlock();
 
 		blk_set_stacking_limits(&q->limits);
@@ -1321,7 +1329,7 @@ static void drbd_setup_queue_param(struct drbd_device *device, struct drbd_backi
 	blk_queue_max_segments(q, max_segments ? max_segments : BLK_MAX_SEGMENTS);
 	blk_queue_segment_boundary(q, PAGE_SIZE-1);
 	decide_on_discard_support(device, q, b, discard_zeroes_if_aligned);
-	decide_on_write_same_support(device, q, b, o);
+	decide_on_write_same_support(device, q, b, o, disable_write_same);
 
 	if (b) {
 		blk_queue_stack_limits(q, b);
@@ -1612,7 +1620,8 @@ int drbd_adm_disk_opts(struct sk_buff *skb, struct genl_info *info)
 	if (write_ordering_changed(old_disk_conf, new_disk_conf))
 		drbd_bump_write_ordering(device->resource, NULL, WO_BDEV_FLUSH);
 
-	if (old_disk_conf->discard_zeroes_if_aligned != new_disk_conf->discard_zeroes_if_aligned)
+	if (old_disk_conf->discard_zeroes_if_aligned != new_disk_conf->discard_zeroes_if_aligned
+	||  old_disk_conf->disable_write_same != new_disk_conf->disable_write_same)
 		drbd_reconsider_queue_parameters(device, device->ldev, NULL);
 
 	drbd_md_sync(device);
@@ -2140,34 +2149,13 @@ int drbd_adm_attach(struct sk_buff *skb, struct genl_info *info)
 
 static int adm_detach(struct drbd_device *device, int force)
 {
-	enum drbd_state_rv retcode;
-	void *buffer;
-	int ret;
-
 	if (force) {
 		set_bit(FORCE_DETACH, &device->flags);
 		drbd_force_state(device, NS(disk, D_FAILED));
-		retcode = SS_SUCCESS;
-		goto out;
+		return SS_SUCCESS;
 	}
 
-	drbd_suspend_io(device); /* so no-one is stuck in drbd_al_begin_io */
-	buffer = drbd_md_get_buffer(device, __func__); /* make sure there is no in-flight meta-data IO */
-	if (buffer) {
-		retcode = drbd_request_state(device, NS(disk, D_FAILED));
-		drbd_md_put_buffer(device);
-	} else /* already <= D_FAILED */
-		retcode = SS_NOTHING_TO_DO;
-	/* D_FAILED will transition to DISKLESS. */
-	drbd_resume_io(device);
-	ret = wait_event_interruptible(device->misc_wait,
-			device->state.disk != D_FAILED);
-	if ((int)retcode == (int)SS_IS_DISKLESS)
-		retcode = SS_NOTHING_TO_DO;
-	if (ret)
-		retcode = ERR_INTR;
-out:
-	return retcode;
+	return drbd_request_detach_interruptible(device);
 }
 
 /* Detaching the disk is a process in multiple stages.  First we need to lock
diff --git a/drivers/block/drbd/drbd_proc.c b/drivers/block/drbd/drbd_proc.c
index 8378142f7a55..582caeb0de86 100644
--- a/drivers/block/drbd/drbd_proc.c
+++ b/drivers/block/drbd/drbd_proc.c
@@ -127,7 +127,7 @@ static void drbd_syncer_progress(struct drbd_device *device, struct seq_file *se
 		seq_putc(seq, '=');
 	seq_putc(seq, '>');
 	for (i = 0; i < y; i++)
-		seq_printf(seq, ".");
+		seq_putc(seq, '.');
 	seq_puts(seq, "] ");
 
 	if (state.conn == C_VERIFY_S || state.conn == C_VERIFY_T)
@@ -179,7 +179,7 @@ static void drbd_syncer_progress(struct drbd_device *device, struct seq_file *se
 	seq_printf_with_thousands_grouping(seq, dbdt);
 	seq_puts(seq, " (");
 	/* ------------------------- ~3s average ------------------------ */
-	if (proc_details >= 1) {
+	if (drbd_proc_details >= 1) {
 		/* this is what drbd_rs_should_slow_down() uses */
 		i = (device->rs_last_mark + DRBD_SYNC_MARKS-1) % DRBD_SYNC_MARKS;
 		dt = (jiffies - device->rs_mark_time[i]) / HZ;
@@ -209,7 +209,7 @@ static void drbd_syncer_progress(struct drbd_device *device, struct seq_file *se
 	}
 	seq_printf(seq, " K/sec%s\n", stalled ? " (stalled)" : "");
 
-	if (proc_details >= 1) {
+	if (drbd_proc_details >= 1) {
 		/* 64 bit:
 		 * we convert to sectors in the display below. */
 		unsigned long bm_bits = drbd_bm_bits(device);
@@ -332,13 +332,13 @@ static int drbd_seq_show(struct seq_file *seq, void *v)
 		    state.conn == C_VERIFY_T)
 			drbd_syncer_progress(device, seq, state);
 
-		if (proc_details >= 1 && get_ldev_if_state(device, D_FAILED)) {
+		if (drbd_proc_details >= 1 && get_ldev_if_state(device, D_FAILED)) {
 			lc_seq_printf_stats(seq, device->resync);
 			lc_seq_printf_stats(seq, device->act_log);
 			put_ldev(device);
 		}
 
-		if (proc_details >= 2)
+		if (drbd_proc_details >= 2)
 			seq_printf(seq, "\tblocked on activity log: %d\n", atomic_read(&device->ap_actlog_cnt));
 	}
 	rcu_read_unlock();
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index c7e95e6380fb..796eaf347dc0 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -332,7 +332,7 @@ static void drbd_free_pages(struct drbd_device *device, struct page *page, int i
 	if (page == NULL)
 		return;
 
-	if (drbd_pp_vacant > (DRBD_MAX_BIO_SIZE/PAGE_SIZE) * minor_count)
+	if (drbd_pp_vacant > (DRBD_MAX_BIO_SIZE/PAGE_SIZE) * drbd_minor_count)
 		i = page_chain_free(page);
 	else {
 		struct page *tmp;
@@ -1100,7 +1100,10 @@ randomize:
 	idr_for_each_entry(&connection->peer_devices, peer_device, vnr)
 		mutex_lock(peer_device->device->state_mutex);
 
+	/* avoid a race with conn_request_state( C_DISCONNECTING ) */
+	spin_lock_irq(&connection->resource->req_lock);
 	set_bit(STATE_SENT, &connection->flags);
+	spin_unlock_irq(&connection->resource->req_lock);
 
 	idr_for_each_entry(&connection->peer_devices, peer_device, vnr)
 		mutex_unlock(peer_device->device->state_mutex);
@@ -1194,6 +1197,14 @@ static int decode_header(struct drbd_connection *connection, void *header, struc
 	return 0;
 }
 
+static void drbd_unplug_all_devices(struct drbd_connection *connection)
+{
+	if (current->plug == &connection->receiver_plug) {
+		blk_finish_plug(&connection->receiver_plug);
+		blk_start_plug(&connection->receiver_plug);
+	} /* else: maybe just schedule() ?? */
+}
+
 static int drbd_recv_header(struct drbd_connection *connection, struct packet_info *pi)
 {
 	void *buffer = connection->data.rbuf;
@@ -1209,6 +1220,36 @@ static int drbd_recv_header(struct drbd_connection *connection, struct packet_in
 	return err;
 }
 
+static int drbd_recv_header_maybe_unplug(struct drbd_connection *connection, struct packet_info *pi)
+{
+	void *buffer = connection->data.rbuf;
+	unsigned int size = drbd_header_size(connection);
+	int err;
+
+	err = drbd_recv_short(connection->data.socket, buffer, size, MSG_NOSIGNAL|MSG_DONTWAIT);
+	if (err != size) {
+		/* If we have nothing in the receive buffer now, to reduce
+		 * application latency, try to drain the backend queues as
+		 * quickly as possible, and let remote TCP know what we have
+		 * received so far. */
+		if (err == -EAGAIN) {
+			drbd_tcp_quickack(connection->data.socket);
+			drbd_unplug_all_devices(connection);
+		}
+		if (err > 0) {
+			buffer += err;
+			size -= err;
+		}
+		err = drbd_recv_all_warn(connection, buffer, size);
+		if (err)
+			return err;
+	}
+
+	err = decode_header(connection, connection->data.rbuf, pi);
+	connection->last_received = jiffies;
+
+	return err;
+}
 /* This is blkdev_issue_flush, but asynchronous.
  * We want to submit to all component volumes in parallel,
  * then wait for all completions.
@@ -1223,7 +1264,7 @@ struct one_flush_context {
 	struct issue_flush_context *ctx;
 };
 
-void one_flush_endio(struct bio *bio)
+static void one_flush_endio(struct bio *bio)
 {
 	struct one_flush_context *octx = bio->bi_private;
 	struct drbd_device *device = octx->device;
@@ -1265,7 +1306,7 @@ static void submit_one_flush(struct drbd_device *device, struct issue_flush_cont
 
 	octx->device = device;
 	octx->ctx = ctx;
-	bio->bi_bdev = device->ldev->backing_bdev;
+	bio_set_dev(bio, device->ldev->backing_bdev);
 	bio->bi_private = octx;
 	bio->bi_end_io = one_flush_endio;
 	bio->bi_opf = REQ_OP_FLUSH | REQ_PREFLUSH;
@@ -1548,7 +1589,7 @@ next_bio:
 	}
 	/* > peer_req->i.sector, unless this is the first bio */
 	bio->bi_iter.bi_sector = sector;
-	bio->bi_bdev = device->ldev->backing_bdev;
+	bio_set_dev(bio, device->ldev->backing_bdev);
 	bio_set_op_attrs(bio, op, op_flags);
 	bio->bi_private = peer_req;
 	bio->bi_end_io = drbd_peer_req