[PATCH] Documentation: block: fix the sector 0 error injection example

The first error injection example is introduced as failing one in ten
reads of sector 0, but the rule it shows does not set nr_sectors, which
defaults to the remainder of the device.  As written it fails one in ten
reads of the whole device.

Add nr_sectors=1 so that the rule does what the text says.  This also
gives the documentation one example that uses nr_sectors.

Fixes: e8dcf2d142bd ("block: add configurable error injection")
Signed-off-by: Md Haris Iqbal <[email protected]>
---
 Documentation/block/error-injection.rst | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Documentation/block/error-injection.rst b/Documentation/block/error-injection.rst
--- a/Documentation/block/error-injection.rst
+++ b/Documentation/block/error-injection.rst
@@ -48,7 +48,7 @@ Example
 
 Return BLK_STS_IOERR for one in 10 reads of sector 0 of /dev/nvme0n1:
 
-	$ echo 'add,op=READ,start=0,status=IOERR,chance=10' > /sys/kernel/debug/block/nvme0n1/error_injection
+	$ echo 'add,op=READ,start=0,nr_sectors=1,status=IOERR,chance=10' > /sys/kernel/debug/block/nvme0n1/error_injection
 
 Return BLK_STS_MEDIUM for every write to /dev/nvme0n1:
 
--
2.53.0