On 5/24/21 3:01 AM, Douglas Gilbert wrote:
The support is added via the new SGV4_FLAG_HIPRI command flag which causes REQ_HIPRI to be set on the request. Before waiting on an inflight request, it is checked to see if it has SGV4_FLAG_HIPRI, and if so blk_poll() is called instead of the wait. In situations where only the file descriptor is known (e.g. sg_poll() and ioctl(SG_GET_NUM_WAITING)) all inflight requests associated with the file descriptor that have SGV4_FLAG_HIPRI set, have blk_poll() called on them. It is important to know blk_execute_rq_nowait() has finished before sending blk_poll() on that request. The SG_RS_INFLIGHT state is set just before blk_execute_rq_nowait() is called so a new bit setting SG_FRQ_ISSUED has been added that is set just after that calls returns. Note that the implementation of blk_poll() calls mq_poll() in the LLD associated with the request. Then for any request found to be ready, blk_poll() invokes the scsi_done() callback. When blk_poll() returns > 0 , sg_rq_end_io() may have been called on the given request. If so the given request will be in await_rcv state. Signed-off-by: Douglas Gilbert <dgilbert@xxxxxxxxxxxx> --- drivers/scsi/sg.c | 111 ++++++++++++++++++++++++++++++++++++++--- include/uapi/scsi/sg.h | 1 + 2 files changed, 106 insertions(+), 6 deletions(-)
Reviewed-by: Hannes Reinecke <hare@xxxxxxx> Cheers, Hannes -- Dr. Hannes Reinecke Kernel Storage Architect hare@xxxxxxx +49 911 74053 688 SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer
