diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c
index 25e0eeb8d498..8a07f04c9203 100644
--- a/fs/proc/kcore.c
+++ b/fs/proc/kcore.c
@@ -307,13 +307,9 @@ static void append_kcore_note(char *notes, size_t *i, const char *name,
 	*i = ALIGN(*i + descsz, 4);
 }
 
-static ssize_t
-read_kcore_iter(struct kiocb *iocb, struct iov_iter *iter)
+static ssize_t read_kcore_iter(struct kiocb *iocb, struct iov_iter *iter)
 {
-	struct file *file = iocb->ki_filp;
-	char *buf = file->private_data;
 	loff_t *ppos = &iocb->ki_pos;
-
 	size_t phdrs_offset, notes_offset, data_offset;
 	size_t page_offline_frozen = 1;
 	size_t phdrs_len, notes_len;
@@ -507,9 +503,7 @@ read_kcore_iter(struct kiocb *iocb, struct iov_iter *iter)
 
 		switch (m->type) {
 		case KCORE_VMALLOC:
-			vread(buf, (char *)start, tsz);
-			/* we have to zero-fill user buffer even if no read */
-			if (copy_to_iter(buf, tsz, iter) != tsz) {
+			if (vread_iter((char *)start, tsz, iter) != tsz) {
 				ret = -EFAULT;
 				goto out;
 			}
@@ -582,10 +576,6 @@ static int open_kcore(struct inode *inode, struct file *filp)
 	if (ret)
 		return ret;
 
-	filp->private_data = kmalloc(PAGE_SIZE, GFP_KERNEL);
-	if (!filp->private_data)
-		return -ENOMEM;
-
 	if (kcore_need_update)
 		kcore_update_ram();
 	if (i_size_read(inode) != proc_root_kcore->size) {
@@ -596,16 +586,9 @@ static int open_kcore(struct inode *inode, struct file *filp)
 	return 0;
 }
 
-static int release_kcore(struct inode *inode, struct file *file)
-{
-	kfree(file->private_data);
-	return 0;
-}
-
 static const struct proc_ops kcore_proc_ops = {
 	.proc_read_iter	= read_kcore_iter,
 	.proc_open	= open_kcore,
-	.proc_release	= release_kcore,
 	.proc_lseek	= default_llseek,
 };
 
diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index 69250efa03d1..f70ebdf21f22 100644
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -9,6 +9,7 @@
 #include <asm/page.h>		/* pgprot_t */
 #include <linux/rbtree.h>
 #include <linux/overflow.h>
+#include <linux/uio.h>
 
 #include <asm/vmalloc.h>
 
@@ -251,7 +252,7 @@ static inline void set_vm_flush_reset_perms(void *addr)
 #endif
 
 /* for /proc/kcore */
-extern long vread(char *buf, char *addr, unsigned long count);
+extern long vread_iter(char *addr, size_t count, struct iov_iter *iter);
 
 /*
  *	Internals.  Don't use..
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index c24b27664a97..3a32754266dc 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -37,7 +37,6 @@
 #include <linux/rbtree_augmented.h>
 #include <linux/overflow.h>
 #include <linux/pgtable.h>
-#include <linux/uaccess.h>
 #include <linux/hugetlb.h>
 #include <linux/sched/mm.h>
 #include <linux/rwsem.h>
@@ -3446,20 +3445,20 @@ EXPORT_SYMBOL(vmalloc_32_user);
  * small helper routine , copy contents to buf from addr.
  * If the page is not present, fill zero.
  */
-
-static int aligned_vread(char *buf, char *addr, unsigned long count)
+static void aligned_vread_iter(char *addr, size_t count,
+			       struct iov_iter *iter)
 {
-	struct page *p;
-	int copied = 0;
+	struct page *page;
 
-	while (count) {
+	while (count > 0) {
 		unsigned long offset, length;
+		size_t copied = 0;
 
 		offset = offset_in_page(addr);
 		length = PAGE_SIZE - offset;
 		if (length > count)
 			length = count;
-		p = vmalloc_to_page(addr);
+		page = vmalloc_to_page(addr);
 		/*
 		 * To do safe access to this _mapped_ area, we need
 		 * lock. But adding lock here means that we need to add
@@ -3467,23 +3466,24 @@ static int aligned_vread(char *buf, char *addr, unsigned long count)
 		 * interface, rarely used. Instead of that, we'll use
 		 * kmap() and get small overhead in this access function.
 		 */
-		if (p) {
+		if (page) {
 			/* We can expect USER0 is not used -- see vread() */
-			void *map = kmap_atomic(p);
-			memcpy(buf, map + offset, length);
-			kunmap_atomic(map);
-		} else
-			memset(buf, 0, length);
+			void *map = kmap_local_page(page);
+
+			copied = copy_to_iter(map + offset, length, iter);
+			kunmap_local(map);
+		}
+
+		if (copied < length)
+			iov_iter_zero(length - copied, iter);
 
 		addr += length;
-		buf += length;
-		copied += length;
 		count -= length;
 	}
-	return copied;
 }
 
-static void vmap_ram_vread(char *buf, char *addr, int count, unsigned long flags)
+static void vmap_ram_vread_iter(char *addr, int count, unsigned long flags,
+				struct iov_iter *iter)
 {
 	char *start;
 	struct vmap_block *vb;
@@ -3496,7 +3496,7 @@ static void vmap_ram_vread(char *buf, char *addr, int count, unsigned long flags
 	 * handle it here.
 	 */
 	if (!(flags & VMAP_BLOCK)) {
-		aligned_vread(buf, addr, count);
+		aligned_vread_iter(addr, count, iter);
 		return;
 	}
 
@@ -3517,22 +3517,24 @@ static void vmap_ram_vread(char *buf, char *addr, int count, unsigned long flags
 		if (!count)
 			break;
 		start = vmap_block_vaddr(vb->va->va_start, rs);
-		while (addr < start) {
+
+		if (addr < start) {
+			size_t to_zero = min_t(size_t, start - addr, count);
+
+			iov_iter_zero(to_zero, iter);
+			addr += to_zero;
+			count -= (int)to_zero;
 			if (count == 0)
 				goto unlock;
-			*buf = '\0';
-			buf++;
-			addr++;
-			count--;
 		}
+
 		/*it could start reading from the middle of used region*/
 		offset = offset_in_page(addr);
 		n = ((re - rs + 1) << PAGE_SHIFT) - offset;
 		if (n > count)
 			n = count;
-		aligned_vread(buf, start+offset, n);
+		aligned_vread_iter(start + offset, n, iter);
 
-		buf += n;
 		addr += n;
 		count -= n;
 	}
@@ -3541,15 +3543,15 @@ static void vmap_ram_vread(char *buf, char *addr, int count, unsigned long flags
 
 finished:
 	/* zero-fill the left dirty or free regions */
-	if (count)
-		memset(buf, 0, count);
+	if (count > 0)
+		iov_iter_zero(count, iter);
 }
 
 /**
- * vread() - read vmalloc area in a safe way.
- * @buf:     buffer for reading data
- * @addr:    vm address.
- * @count:   number of bytes to be read.
+ * vread_iter() - read vmalloc area in a safe way to an iterator.
+ * @addr:         vm address.
+ * @count:        number of bytes to be read.
+ * @iter:         the iterator to which data should be written.
  *
  * This function checks that addr is a valid vmalloc'ed area, and
  * copy data from that area to a given buffer. If the given memory range
@@ -3569,13 +3571,13 @@ static void vmap_ram_vread(char *buf, char *addr, int count, unsigned long flags
  * (same number as @count) or %0 if [addr...addr+count) doesn't
  * include any intersection with valid vmalloc area
  */
-long vread(char *buf, char *addr, unsigned long count)
+long vread_iter(char *addr, size_t count, struct iov_iter *iter)
 {
 	struct vmap_area *va;
 	struct vm_struct *vm;
-	char *vaddr, *buf_start = buf;
-	unsigned long buflen = count;
-	unsigned long n, size, flags;
+	char *vaddr;
+	size_t buflen = count;
+	size_t n, size, flags;
 
 	might_sleep();
 
@@ -3595,7 +3597,7 @@ long vread(char *buf, char *addr, unsigned long count)
 		goto finished;
 
 	list_for_each_entry_from(va, &vmap_area_list, list) {
-		if (!count)
+		if (count == 0)
 			break;
 
 		vm = va->vm;
@@ -3619,36 +3621,39 @@ long vread(char *buf, char *addr, unsigned long count)
 
 		if (addr >= vaddr + size)
 			continue;
-		while (addr < vaddr) {
+
+		if (addr < vaddr) {
+			size_t to_zero = min_t(size_t, vaddr - addr, count);
+
+			iov_iter_zero(to_zero, iter);
+			addr += to_zero;
+			count -= to_zero;
 			if (count == 0)
 				goto finished;
-			*buf = '\0';
-			buf++;
-			addr++;
-			count--;
 		}
+
 		n = vaddr + size - addr;
 		if (n > count)
 			n = count;
 
 		if (flags & VMAP_RAM)
-			vmap_ram_vread(buf, addr, n, flags);
+			vmap_ram_vread_iter(addr, n, flags, iter);
 		else if (!(vm->flags & VM_IOREMAP))
-			aligned_vread(buf, addr, n);
+			aligned_vread_iter(addr, n, iter);
 		else /* IOREMAP area is treated as memory hole */
-			memset(buf, 0, n);
-		buf += n;
+			iov_iter_zero(n, iter);
+
 		addr += n;
 		count -= n;
 	}
 finished:
 	up_read(&vmap_area_lock);
 
-	if (buf == buf_start)
+	if (count == buflen)
 		return 0;
 	/* zero-fill memory holes */
-	if (buf != buf_start + buflen)
-		memset(buf, 0, buflen - (buf - buf_start));
+	if (count > 0)
+		iov_iter_zero(count, iter);
 
 	return buflen;
 }
