diff --git a/block/bio.c b/block/bio.c
index 9d70ebe4122cf3898674851be72f1ea5f2070f12..06193e854577e1ecff96d66b4f382084ceedd2a5 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1733,8 +1733,9 @@ void update_io_ticks(int cpu, struct hd_struct *part, unsigned long now, bool en
 	}
 }
 
-void generic_start_io_acct(struct request_queue *q, int op,
-			   unsigned long sectors, struct hd_struct *part)
+static void __generic_start_io_acct(struct request_queue *q, int op,
+				    unsigned long sectors,
+				    struct hd_struct *part, bool precise)
 {
 	const int sgrp = op_stat_group(op);
 	int cpu = part_stat_lock();
@@ -1743,16 +1744,33 @@ void generic_start_io_acct(struct request_queue *q, int op,
 		part_round_stats(q, cpu, part);
 	else
 		update_io_ticks(cpu, part, jiffies, false);
-	part_stat_inc(cpu, part, ios[sgrp]);
-	part_stat_add(cpu, part, sectors[sgrp], sectors);
+	if (!precise) {
+		part_stat_inc(cpu, part, ios[sgrp]);
+		part_stat_add(cpu, part, sectors[sgrp], sectors);
+	}
 	part_inc_in_flight(q, part, op_is_write(op));
 
 	part_stat_unlock();
 }
+
+void generic_start_io_acct(struct request_queue *q, int op,
+			   unsigned long sectors, struct hd_struct *part)
+{
+	__generic_start_io_acct(q, op, sectors, part, false);
+}
 EXPORT_SYMBOL(generic_start_io_acct);
 
-void generic_end_io_acct(struct request_queue *q, int req_op,
-			 struct hd_struct *part, unsigned long start_time)
+void generic_start_precise_io_acct(struct request_queue *q, int op,
+				   struct hd_struct *part)
+{
+	__generic_start_io_acct(q, op, 0, part, true);
+}
+EXPORT_SYMBOL(generic_start_precise_io_acct);
+
+static void __generic_end_io_acct(struct request_queue *q, int req_op,
+				  struct hd_struct *part,
+				  unsigned long start_time,
+				  unsigned long sectors, bool precise)
 {
 	unsigned long now = jiffies;
 	unsigned long duration = now - start_time;
@@ -1765,13 +1783,32 @@ void generic_end_io_acct(struct request_queue *q, int req_op,
 		update_io_ticks(cpu, part, now, true);
 		part_stat_add(cpu, part, time_in_queue, duration);
 	}
+	if (precise) {
+		part_stat_inc(cpu, part, ios[sgrp]);
+		part_stat_add(cpu, part, sectors[sgrp], sectors);
+	}
 	part_stat_add(cpu, part, nsecs[sgrp], jiffies_to_nsecs(duration));
 	part_dec_in_flight(q, part, op_is_write(req_op));
 
 	part_stat_unlock();
 }
+
+void generic_end_io_acct(struct request_queue *q, int req_op,
+			 struct hd_struct *part, unsigned long start_time)
+{
+	__generic_end_io_acct(q, req_op, part, start_time, 0, false);
+}
 EXPORT_SYMBOL(generic_end_io_acct);
 
+void generic_end_precise_io_acct(struct request_queue *q, int req_op,
+				 struct hd_struct *part,
+				 unsigned long start_time,
+				 unsigned long sectors)
+{
+	__generic_end_io_acct(q, req_op, part, start_time, sectors, true);
+}
+EXPORT_SYMBOL(generic_end_precise_io_acct);
+
 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 void bio_flush_dcache_pages(struct bio *bi)
 {
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 0aa6fd33abf1aeece9c8f14979b573cf7b3928db..1d2ae304f09652293ad2851939293b9103d7fff1 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -621,8 +621,8 @@ static void start_io_acct(struct dm_io *io)
 
 	io->start_time = jiffies;
 
-	generic_start_io_acct(md->queue, bio_op(bio), bio_sectors(bio),
-			      &dm_disk(md)->part0);
+	generic_start_precise_io_acct(md->queue, bio_op(bio),
+				      &dm_disk(md)->part0);
 
 	atomic_set(&dm_disk(md)->part0.in_flight[rw],
 		   atomic_inc_return(&md->pending[rw]));
@@ -640,8 +640,8 @@ static void end_io_acct(struct mapped_device *md, struct bio *bio,
 	int pending;
 	int rw = bio_data_dir(bio);
 
-	generic_end_io_acct(md->queue, bio_op(bio), &dm_disk(md)->part0,
-			    start_time);
+	generic_end_precise_io_acct(md->queue, bio_op(bio), &dm_disk(md)->part0,
+				    start_time, bio_sectors(bio));
 
 	if (unlikely(dm_stats_used(&md->stats)))
 		dm_stats_account_io(&md->stats, bio_data_dir(bio),
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 361b1bcd3debd940b68766f170785841fee82ce3..6a41b7b70d88ac240e575ca52e9159dbd2b068a0 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -497,6 +497,12 @@ void generic_start_io_acct(struct request_queue *q, int op,
 void generic_end_io_acct(struct request_queue *q, int op,
 				struct hd_struct *part,
 				unsigned long start_time);
+void generic_start_precise_io_acct(struct request_queue *q, int op,
+				   struct hd_struct *part);
+void generic_end_precise_io_acct(struct request_queue *q, int op,
+				 struct hd_struct *part,
+				 unsigned long start_time,
+				 unsigned long secotors);
 
 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 # error	"You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"