On 12 November 2015 at 01:54, Mike Snitzer <snitzer@xxxxxxxxxx> wrote: > On Wed, Nov 11 2015 at 4:31am -0500, > Baolin Wang <baolin.wang@xxxxxxxxxx> wrote: > >> When we use dm-crypt to decrypt block data, it will decrypt the block data >> in endio() when one IO is completed. In this situation we don't want the >> cloned bios is freed before calling the endio(). >> >> Thus introduce 'BIO_ENDIO_FREE' flag to support the request handling for dm-crypt, >> this flag will ensure that blk layer does not complete the cloned bios before >> completing the request. When the crypt endio is called, post-processsing is >> done and then the dm layer will complete the bios (clones) and free them. > > Not following why request-based DM's partial completion handling > (drivers/md/dm.c:end_clone_bio) isn't a sufficient hook -- no need to > add block complexity. > Sorry for lacking of more explanation for that. The dm-crypt will decrypt block data in the end_io() callback function when one request is completed, so we don't want the bios of this request is freed when calling the end_io() callback. Thus we introduce a flag to indicate these type bios of this request will be freed at dm layer not in block layer. > But that aside, I'm not liking the idea of a request-based dm-crypt. > >> diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h >> index 76d23fa..f636c50 100644 >> --- a/include/linux/device-mapper.h >> +++ b/include/linux/device-mapper.h >> @@ -407,6 +407,11 @@ union map_info *dm_get_rq_mapinfo(struct request *rq); >> >> struct queue_limits *dm_get_queue_limits(struct mapped_device *md); >> >> +void dm_end_request(struct request *clone, int error); >> +void dm_kill_unmapped_request(struct request *rq, int error); >> +void dm_dispatch_clone_request(struct request *clone, struct request *rq); >> +struct request *dm_get_orig_rq(struct request *clone); >> + >> /* >> * Geometry functions. >> */ > > I have no interest in seeing any request-based DM interfaces exported. OK. -- Baolin.wang Best Regards -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
