Hi Dan, Thanks for the review. I'm still working thru this, but a clarifying question below...
On Wed, Jan 26, 2022 at 03:41:14PM -0800, Dan Williams wrote: > On Tue, Jan 18, 2022 at 12:20 PM <[email protected]> wrote: > > > > From: Alison Schofield <[email protected]> > > > > Users may want the ability to change the partition layout of a CXL > > memory device. > > > > Add interfaces to libcxl to allocate and send a SET_PARTITION_INFO > > mailbox as defined in the CXL 2.0 specification. > > > > Signed-off-by: Alison Schofield <[email protected]> > > --- > > cxl/lib/libcxl.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++ > > cxl/lib/libcxl.sym | 5 +++++ > > cxl/lib/private.h | 8 ++++++++ > > cxl/libcxl.h | 5 +++++ > > 4 files changed, 68 insertions(+) > > snip > > > I don't understand what this is for? > > Let's back up. In order to future proof against spec changes, and > endianness, struct packing and all other weird things that make struct > ABIs hard to maintain compatibility the ndctl project adopts the > libabc template of just not letting library consumers see any raw data > structures or bit fields by default [1]. For a situation like this > since the command only has one flag that affects the mode of operation > I would just go ahead and define an enum for that explicitly. > > enum cxl_setpartition_mode { > CXL_SETPART_NONE, > CXL_SETPART_NEXTBOOT, > CXL_SETPART_IMMEDIATE, > }; > > Then the main function prototype becomes: > > int cxl_cmd_new_setpartition(struct cxl_memdev *memdev, unsigned long > long volatile_capacity); > > ...with a new: > > int cxl_cmd_setpartition_set_mode(struct cxl_cmd *cmd, enum > cxl_setpartition_mode mode); > I don't understand setting of the mode separately. Can it be: int cxl_cmd_new_setpartition(struct cxl_memdev *memdev, unsigned long long volatile_capacity, enum cxl_setpartition_mode mode); > ...and it becomes impossible for users to pass unsupported flag > values. If the specification later on adds more flags then we can add > more: > > int cxl_cmd_setpartition_set_<X>(struct cxl_cmd *cmd, enum > cxl_setpartition_X x); > > ...style helpers. > > Note, I was thinking CXL_SETPART_NONE is there to catch API users that > forget to set a mode, but I also don't mind skipping that and just > defaulting cxl_cmd_new_setpartition() to CXL_SETPART_NEXTBOOT, up to > you. > > [1]: > https://git.kernel.org/pub/scm/linux/kernel/git/kay/libabc.git/tree/README#n99
