Jens Axboe wrote: > On Sat, Sep 09 2006, Mike Christie wrote: >> Currently, there is some duplication between bsg, scsi_ioctl.c >> and scsi_lib.c/sg/st in its mapping code. This patch modifies >> the block layer blk_rq_map_user code to support large requests so >> that the scsi and block drivers can use this common code. The >> changes also make it so the callers do not have to account for >> the bio to be unmapped and bounce buffers. >> >> The next patch then coverts bsg.c, scsi_ioctl.c and cdrom.c >> to use the updated functions. For scsi_ioctl.c and cdrom.c >> the only thing that changes is that they no longer have >> to do the bounce buffer management and pass in the len for >> the unmapping. The bsg change is a little larger since that >> code was duplicating a lot of code that is now common >> in the block layer. The bsg conversions als should fix >> a memory leak caused when unmapping a hdr with iovec_count=0. >> >> Patch was made over Jens's block tree and the bsg branch > > Generally it looks good - two comments: > > - I see some advantages to having biohead_orig to avoid keeping track of > it and passing it around, but there's also good reasons for _not_ > adding more stuff to struct request. Any particular reason you chose > to do that? I think I originally made a mistake with the bounce buffers and thinking that others may do the same I felt that hiding a lot of the magic that is going on in blk_rq_map_user was nice. By adding the field to the request, the caller would only have to map the data and then unmap the request. Since not even a handful of drivers would ever use the api, I agree that adding the field for this limited use could be overkill. > > - blk_get_bounced_bio() looks redundant. BIO_BOUNCED should only be set > on a bounced bio, and ->bi_private should always hold that bounced > bio. > Ok, I will remove that. - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
