• Tejun Heo's avatar
    block: add request->raw_data_len · 6b00769f
    Tejun Heo authored
    With padding and draining moved into it, block layer now may extend
    requests as directed by queue parameters, so now a request has two
    sizes - the original request size and the extended size which matches
    the size of area pointed to by bios and later by sgs.  The latter size
    is what lower layers are primarily interested in when allocating,
    filling up DMA tables and setting up the controller.
    Both padding and draining extend the data area to accomodate
    controller characteristics.  As any controller which speaks SCSI can
    handle underflows, feeding larger data area is safe.
    So, this patch makes the primary data length field, request->data_len,
    indicate the size of full data area and add a separate length field,
    request->raw_data_len, for the unmodified request size.  The latter is
    used to report to higher layer (userland) and where the original
    request size should be fed to the controller or device.
    Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
    Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
    Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
scsi_lib.c 62.5 KB