[PATCH] bs= and bsrange= takes both read and write sizes

Get rid of read_bs/write_bs and read_bsrange/write_bsrange. It was ugly
and too complicated. Instead support giving both values in a single bs=
or bsrange= seperated by a comma.

Example: bs=1k,4k will use 1k blocks for reads, 4k blocks for writes.
	 bs=32k will use 32k blocks for both reads and writes.

Similar for bsrange=

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/HOWTO b/HOWTO
index 2616156..1e1f409 100644
--- a/HOWTO
+++ b/HOWTO
@@ -218,22 +218,20 @@
 		size if larger than the current file size. If this parameter
 		is not given and the file exists, the file size will be used.
 
-bs=siint	The block size used for the io units. Defaults to 4k.
-
-read_bs=siint
-write_bs=siint	If the workload is a mixed read-write workload, you can use
-		these options to set separate block sizes.
+bs=siint	The block size used for the io units. Defaults to 4k. Values
+		can be given for both read and writes. If a single siint is
+		given, it will apply to both. If a second siint is specified
+		after a comma, it will apply to writes only. In other words,
+		the format is either bs=read_and_write or bs=read,write.
+		bs=4k,8k will thus use 4k blocks for reads, and 8k blocks
+		for writes.
 
 bsrange=irange	Instead of giving a single block size, specify a range
 		and fio will mix the issued io block sizes. The issued
 		io unit will always be a multiple of the minimum value
-		given (also see bs_unaligned).
-
-read_bsrange=irange
-write_bsrange=irange
-		If the workload is a mixed read-write workload, you can use
-		one of these options to set separate block size ranges for
-		reads and writes.
+		given (also see bs_unaligned). Applies to both reads and
+		writes, however a second range can be given after a comma.
+		See bs=.
 
 bs_unaligned	If this option is given, any byte size value within bsrange
 		may be used as a block range. This typically wont work with