Logic sets a value and then reads it back to make sure it worked
and retries write on failures. Since read and write share a buffer,
it needs to be set back up before writing though.
Issue is not seen a lot because 1) it doesn't need to retry for
a lot of tablets and 2) a lot of failures that need a retry are
from an -ETIMEDOUT and hopefully buffer is not touched in this case.
At least one user has shown logs with buffer being modified during
-ETIMEDOUT case with linux 3.7 kernel.
Signed-off-by: Chris Bagwell <chris@cnpbagwell.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>