4 files changed, 11 insertions, 45 deletions

diff --git a/drivers/block/aoe/aoecmd.c b/drivers/block/aoe/aoecmd.c
index ab19adb07a12..3c606c09fd5a 100644
--- a/drivers/block/aoe/aoecmd.c
+++ b/drivers/block/aoe/aoecmd.c
@@ -853,45 +853,6 @@ rqbiocnt(struct request *r)
 	return n;
 }
 
-/* This can be removed if we are certain that no users of the block
- * layer will ever use zero-count pages in bios.  Otherwise we have to
- * protect against the put_page sometimes done by the network layer.
- *
- * See http://oss.sgi.com/archives/xfs/2007-01/msg00594.html for
- * discussion.
- *
- * We cannot use get_page in the workaround, because it insists on a
- * positive page count as a precondition.  So we use _refcount directly.
- */
-static void
-bio_pageinc(struct bio *bio)
-{
-	struct bio_vec bv;
-	struct page *page;
-	struct bvec_iter iter;
-
-	bio_for_each_segment(bv, bio, iter) {
-		/* Non-zero page count for non-head members of
-		 * compound pages is no longer allowed by the kernel.
-		 */
-		page = compound_head(bv.bv_page);
-		page_ref_inc(page);
-	}
-}
-
-static void
-bio_pagedec(struct bio *bio)
-{
-	struct page *page;
-	struct bio_vec bv;
-	struct bvec_iter iter;
-
-	bio_for_each_segment(bv, bio, iter) {
-		page = compound_head(bv.bv_page);
-		page_ref_dec(page);
-	}
-}
-
 static void
 bufinit(struct buf *buf, struct request *rq, struct bio *bio)
 {
@@ -899,7 +860,6 @@ bufinit(struct buf *buf, struct request *rq, struct bio *bio)
 	buf->rq = rq;
 	buf->bio = bio;
 	buf->iter = bio->bi_iter;
-	bio_pageinc(bio);
 }
 
 static struct buf *
@@ -1127,7 +1087,6 @@ aoe_end_buf(struct aoedev *d, struct buf *buf)
 	if (buf == d->ip.buf)
 		d->ip.buf = NULL;
 	rq = buf->rq;
-	bio_pagedec(buf->bio);
 	mempool_free(buf, d->bufpool);
 	n = (unsigned long) rq->special;
 	rq->special = (void *) --n;
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 100be556e613..83482721bc01 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -1871,7 +1871,7 @@ int drbd_send(struct drbd_connection *connection, struct socket *sock,
 		drbd_update_congested(connection);
 	}
 	do {
-		rv = kernel_sendmsg(sock, &msg, &iov, 1, size);
+		rv = kernel_sendmsg(sock, &msg, &iov, 1, iov.iov_len);
 		if (rv == -EAGAIN) {
 			if (we_should_drop_the_connection(connection, sock))
 				break;
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 19a16b2dbb91..7a1048755914 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -599,7 +599,7 @@ static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
 			return -EINVAL;
 
 		sreq = blk_mq_alloc_request(bdev_get_queue(bdev), WRITE, 0);
-		if (!sreq)
+		if (IS_ERR(sreq))
 			return -ENOMEM;
 
 		mutex_unlock(&nbd->tx_lock);
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 511c35fd5c6f..15f58ab44d0b 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1404,7 +1404,8 @@ static ssize_t hot_remove_store(struct class *class,
 	zram = idr_find(&zram_index_idr, dev_id);
 	if (zram) {
 		ret = zram_remove(zram);
-		idr_remove(&zram_index_idr, dev_id);
+		if (!ret)
+			idr_remove(&zram_index_idr, dev_id);
 	} else {
 		ret = -ENODEV;
 	}
@@ -1413,8 +1414,14 @@ static ssize_t hot_remove_store(struct class *class,
 	return ret ? ret : count;
 }
 
+/*
+ * NOTE: hot_add attribute is not the usual read-only sysfs attribute. In a
+ * sense that reading from this file does alter the state of your system -- it
+ * creates a new un-initialized zram device and returns back this device's
+ * device_id (or an error code if it fails to create a new device).
+ */
 static struct class_attribute zram_control_class_attrs[] = {
-	__ATTR_RO(hot_add),
+	__ATTR(hot_add, 0400, hot_add_show, NULL),
 	__ATTR_WO(hot_remove),
 	__ATTR_NULL,
 };