On Thu, May 7, 2015 at 8:58 AM, Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: > On Thu, May 7, 2015 at 8:40 AM, Dan Williams <dan.j.williams@xxxxxxxxx> wrote: >> >> blkdev_get(FMODE_EXCL) is the protection in this case. > > Ugh. That looks like a horrible nasty big hammer that will bite us > badly some day. Since you'd have to hold it for the whole IO. But I > guess it at least works. Oh no, that wouldn't be per-I/O that would be permanent at configuration set up time just like a raid member device. Something like: mdadm --create /dev/md0 --cache=/dev/pmem0p1 --storage=/dev/sda > Anyway, I did want to say that while I may not be convinced about the > approach, I think the patches themselves don't look horrible. I > actually like your "__pfn_t". So while I (very obviously) have some > doubts about this approach, it may be that the most convincing > argument is just in the code. Ok, I'll keep thinking about this and come back when we have a better story about passing mmap'd persistent memory around in userspace. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
