sysfs: fix drivers/block so if an attribute doesn't implement
       show or store method read/write will return -EIO
       instead of 0 or -EINVAL.
Signed-off-by: NDmitry Torokhov <dtor@mail.ru>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

__cfq_get_queue().  __cfq_get_queue() finds an existing queue (struct
cfq_queue) of the current process for the device and returns it.  If it's not
found, __cfq_get_queue() creates and returns a new one if __cfq_get_queue() is
called with __GFP_WAIT flag, or __cfq_get_queue() returns NULL (this means that
get_request() fails) if no __GFP_WAIT flag.

On the other hand, in __make_request(), get_request() is called without
__GFP_WAIT flag at the first time.  Thus, the get_request() fails when there is
no existing queue, typically when it's called for the first I/O request of the
process to the device.

Though it will be followed by get_request_wait() for general case,
__make_request() will just end the I/O with an error (EWOULDBLOCK) when the
request was for read-ahead.
Signed-off-by: NJens Axboe <axboe@suse.de>
Signed-off-by: NKiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: NJun'ichi Nomura <j-nomura@ce.jp.nec.com>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!