diff --git a/block/bio.c b/block/bio.c
index 21c56c177b250197cd2bc691d91bda202247ebe0..acefd2be1cd97ed9c00ba04eb3ddef14279f501e 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -547,6 +547,45 @@ void zero_fill_bio_iter(struct bio *bio, struct bvec_iter start)
 }
 EXPORT_SYMBOL(zero_fill_bio_iter);
 
+void bio_truncate(struct bio *bio, unsigned new_size)
+{
+	struct bio_vec bv;
+	struct bvec_iter iter;
+	unsigned int done = 0;
+	bool truncated = false;
+
+	if (new_size >= bio->bi_iter.bi_size)
+		return;
+
+	if (bio_data_dir(bio) != READ)
+		goto exit;
+
+	bio_for_each_segment(bv, bio, iter) {
+		if (done + bv.bv_len > new_size) {
+			unsigned offset;
+
+			if (!truncated)
+				offset = new_size - done;
+			else
+				offset = 0;
+			zero_user(bv.bv_page, offset, bv.bv_len - offset);
+			truncated = true;
+		}
+		done += bv.bv_len;
+	}
+
+ exit:
+	/*
+	 * Don't touch bvec table here and make it really immutable, since
+	 * fs bio user has to retrieve all pages via bio_for_each_segment_all
+	 * in its .end_bio() callback.
+	 *
+	 * It is enough to truncate bio by updating .bi_size since we can make
+	 * correct bvec with the updated .bi_size for drivers.
+	 */
+	bio->bi_iter.bi_size = new_size;
+}
+
 /**
  * bio_put - release a reference to a bio
  * @bio:   bio to release reference to
diff --git a/fs/buffer.c b/fs/buffer.c
index ea8a7b6efdf5036a1c2ec995505daa328779db9b..6be882a23758bdf26e33da31a0fa9ca65c30b28b 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -2993,8 +2993,6 @@ static void end_bio_bh_io_sync(struct bio *bio)
 void guard_bio_eod(int op, struct bio *bio)
 {
 	sector_t maxsector;
-	struct bio_vec *bvec = bio_last_bvec_all(bio);
-	unsigned truncated_bytes;
 	struct hd_struct *part;
 
 	rcu_read_lock();
@@ -3020,25 +3018,7 @@ void guard_bio_eod(int op, struct bio *bio)
 	if (likely((bio->bi_iter.bi_size >> 9) <= maxsector))
 		return;
 
-	/* Uhhuh. We've got a bio that straddles the device size! */
-	truncated_bytes = bio->bi_iter.bi_size - (maxsector << 9);
-
-	/*
-	 * The bio contains more than one segment which spans EOD, just return
-	 * and let IO layer turn it into an EIO
-	 */
-	if (truncated_bytes > bvec->bv_len)
-		return;
-
-	/* Truncate the bio.. */
-	bio->bi_iter.bi_size -= truncated_bytes;
-	bvec->bv_len -= truncated_bytes;
-
-	/* ..and clear the end of the buffer for reads */
-	if (op == REQ_OP_READ) {
-		zero_user(bvec->bv_page, bvec->bv_offset + bvec->bv_len,
-				truncated_bytes);
-	}
+	bio_truncate(bio, maxsector << 9);
 }
 
 static int submit_bh_wbc(int op, int op_flags, struct buffer_head *bh,
diff --git a/include/linux/bio.h b/include/linux/bio.h
index b2413f682aba786263e0c177e5665b50c5f07602..361b1bcd3debd940b68766f170785841fee82ce3 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -521,6 +521,7 @@ extern struct bio *bio_copy_user_iov(struct request_queue *,
 				     gfp_t);
 extern int bio_uncopy_user(struct bio *);
 void zero_fill_bio_iter(struct bio *bio, struct bvec_iter iter);
+void bio_truncate(struct bio *bio, unsigned new_size);
 
 static inline void zero_fill_bio(struct bio *bio)
 {