Hi Dan, Thanks for your review.
On Fri, Jun 03, 2016 at 12:27:34PM -0700, Dan Williams wrote: > On Fri, Jun 3, 2016 at 12:13 AM, Lee, Chun-Yi <joeyli.ker...@gmail.com> wrote: > > This patch adds codes to treat a volatile virtual CD region as a > > read-only pmem region, then read-only /dev/pmem* device can be mounted > > with iso9660. > > > > It's useful to work with the httpboot in EFI firmware to pull a remote > > ISO file to the local memory region for booting and installation. > > > > Wiki page of UEFI HTTPBoot with OVMF: > > https://en.opensuse.org/UEFI_HTTPBoot_with_OVMF > > > > Signed-off-by: Lee, Chun-Yi <j...@suse.com> > > Cc: Gary Lin <g...@suse.com> > > Cc: Dan Williams <dan.j.willi...@intel.com> > > Cc: Ross Zwisler <ross.zwis...@linux.intel.com> > > Cc: "Rafael J. Wysocki" <r...@rjwysocki.net> > > --- > > drivers/acpi/nfit.c | 8 +++++++- > > drivers/nvdimm/region_devs.c | 26 +++++++++++++++++++++++++- > > include/linux/libnvdimm.h | 2 ++ > > 3 files changed, 34 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit.c > > index 2215fc8..b100a17 100644 > > --- a/drivers/acpi/nfit.c > > +++ b/drivers/acpi/nfit.c > > @@ -1949,6 +1949,7 @@ static int acpi_nfit_init_mapping(struct > > acpi_nfit_desc *acpi_desc, > > switch (nfit_spa_type(spa)) { > > case NFIT_SPA_PM: > > case NFIT_SPA_VOLATILE: > > + case NFIT_SPA_VCD: > > nd_mapping->start = memdev->address; > > nd_mapping->size = memdev->region_size; > > break; > > Why do we need to distinguish NFIT_SPA_VOLATILE vs NFIT_SPA_VCD, i.e. > what happens if something writes to a VCD device? Actually I didn't try to write SPA-VCD device before. Every time I mount it that the system responses read-only: # mount /dev/pmem0 /mnt/ mount: /dev/pmem0 is write-protected, mounting read-only If it can be written, then I think there have no difference between NFIT_SPA_VOLATILE with NFIT_SPA_VCD region. I implemented this patch to treat VCD region as read-only pmem because the pmem region generates /dev/pmem* device that it can be mounted. Maybe I missed. Does NFIT_SPA_VOLATILE region also generate a device in /dev that it can be mounted with filesystem? Then I think treat the VCD region as a read-only VOLATILE region that's also a solution. Thanks a lot! Joey Lee
