On Fri, Dec 23, 2016 at 11:42:45AM -0800, Linus Torvalds wrote: > Ugh. This patch is nasty.
It's the same SCSI has done for ages - except that is uses a separate kmalloc for the sense buffer. > I think we should just fix blk_execute_rq() instead. As you found out below it's not just blk_execute_rq, it's the whole architecture of the BLOCK_PC code, which expects a caller provided sense buffer. But with the way blk-mq allocates request structures we can actually fix it, but I first need to extent the way it allows drivers to allocate private data to the old request code. I've actually already implemented that for SCSI long time ago, and have started to life it to the block layer. Once that is done the callers won't need a sense buffer at all, and can just look at the driver provided one. Which currently is missing in virtio-blk, so we'd need something similar to the above patch anyway.
