From: Kiyoshi Ueda Date: Tue, 11 Dec 2007 22:51:02 +0000 (-0500) Subject: blk_end_request: add callback feature (take 4) X-Git-Tag: v2.6.25-rc1~1172^2~8 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e19a3ab058fe91c8c54d43dc56dccf7eb386478e;p=pandora-kernel.git blk_end_request: add callback feature (take 4) This patch adds a variant of the interface, blk_end_request_callback(), which has driver callback feature. Drivers may need to do special works between end_that_request_first() and end_that_request_last(). For such drivers, blk_end_request_callback() allows it to pass a callback function which is called between end_that_request_first() and end_that_request_last(). This interface is only for fallback of other blk_end_request interfaces. Drivers should avoid their tricky behaviors and use other interfaces as much as possible. Currently, only one driver, ide-cd, needs this interface. So this interface should/will be removed, after the driver removes such tricky behaviors. o ide-cd (cdrom_newpc_intr()) In PIO mode, cdrom_newpc_intr() needs to defer end_that_request_last() until the device clears DRQ_STAT and raises an interrupt after end_that_request_first(). So end_that_request_first() and end_that_request_last() are called separately in cdrom_newpc_intr(). This means blk_end_request_callback() has to return without completing request even if no leftover in the request. To satisfy the requirement, callback function has return value so that drivers can tell blk_end_request_callback() to return without completing request. Signed-off-by: Kiyoshi Ueda Signed-off-by: Jun'ichi Nomura Signed-off-by: Jens Axboe --- Reading git-diff-tree failed