1. 19 6月, 2005 23 次提交
  2. 18 6月, 2005 16 次提交
  3. 17 6月, 2005 1 次提交
    • K
      When cfq I/O scheduler is selected, get_request() in __make_request() calls · db3b5848
      Kiyoshi Ueda 提交于
      __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>
      db3b5848