On Fri, Jun 19, 2015 at 12:14 PM, Mikulas Patocka <mpatocka@xxxxxxxxxx> wrote: > > > On Fri, 19 Jun 2015, Dan Williams wrote: > >> On Fri, Jun 19, 2015 at 9:33 AM, Mikulas Patocka <mpatocka@xxxxxxxxxx> wrote: >> > Hi >> > >> > I looked at the new the persistent memory block device driver >> > (drivers/block/pmem.c and arch/x86/kernel/pmem.c) and it seems that the >> > interface between them is incorrect. >> > >> > If I want to use persistent memory in another driver, for a different >> > purpose, how can I make sure that that drivers/block/pmem.c doesn't attach >> > to this piece of memory and export it? It seems not possible. >> > drivers/block/pmem.c attaches to everything without regard that there may >> > be other users of persistent memory. >> >> Simply partition the pmem device however you see fit and then >> blkdev_get_by_path(<dev>, FMODE_EXCL, <holder>) the resulting >> partition(s). > > But that still means accessing it through the block layer. > > I need to access persistent memory directly - map it into the kernel space > and access it as mapped memory - and if I do it, it will fight with > drivers/block/pmem.c over ownership of the memory :-( > See the latest definition of struct block_device_operations in these patches. We now have ->direct_access() in the 4.0 kernel and will have ->rw_bytes() in the 4.2 kernel if you want to directly access the memory published by a pmem device. -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
