On Wed, 9 Nov 2016 02:16:17 +0530
Kirti Wankhede <kwankhede@xxxxxxxxxx> wrote:
> On 11/8/2016 12:59 PM, Alexey Kardashevskiy wrote:
> > On 05/11/16 08:10, Kirti Wankhede wrote:
> >> Vendor driver using mediated device framework should use
> >> vfio_info_add_capability() to add capabilities.
> >> Introduced this function to reduce code duplication in vendor drivers.
> >>
> >> Signed-off-by: Kirti Wankhede <kwankhede@xxxxxxxxxx>
> >> Signed-off-by: Neo Jia <cjia@xxxxxxxxxx>
> >> Change-Id: I6fca329fa2291f37a2c859d0bc97574d9e2ce1a6
> >> ---
> >> drivers/vfio/vfio.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++++++-
> >> include/linux/vfio.h | 3 +++
> >> 2 files changed, 62 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
> >> index 4ed1a6a247c6..9a03be0942a1 100644
> >> --- a/drivers/vfio/vfio.c
> >> +++ b/drivers/vfio/vfio.c
> >> @@ -1797,8 +1797,66 @@ void vfio_info_cap_shift(struct vfio_info_cap *caps, size_t offset)
> >> for (tmp = caps->buf; tmp->next; tmp = (void *)tmp + tmp->next - offset)
> >> tmp->next += offset;
> >> }
> >> -EXPORT_SYMBOL_GPL(vfio_info_cap_shift);
> >> +EXPORT_SYMBOL(vfio_info_cap_shift);
> >
> >
> > Why this change?
> >
> >
>
> We want this symbol to be available to all drivers.
IOW, from proprietary drivers. It makes me uncomfortable how many
non-GPL symbols we're adding (or converting) in this effort, but I'm
trying to look objectively at every export as to whether a non-GPL
caller of the function is legitimately separate from in-kernel code.
For instance are they making use of data structures intrinsic to GPL'd
code. In this case we're converting a symbol that's just manipulating
a data buffer to add an offset to each element in a chain. The entries
are documented in a uapi header. Kirti asked me about this one, and I
couldn't find any basis to raise an objection. If you spot any reason
that any of the export symbols in these series really should be GPL,
please raise the issue.
> >>
> >> +static int sparse_mmap_cap(struct vfio_info_cap *caps, void *cap_type)
> >> +{
> >> + struct vfio_info_cap_header *header;
> >> + struct vfio_region_info_cap_sparse_mmap *sparse_cap, *sparse = cap_type;
> >> + size_t size;
> >> +
> >> + size = sizeof(*sparse) + sparse->nr_areas * sizeof(*sparse->areas);
> >> + header = vfio_info_cap_add(caps, size,
> >> + VFIO_REGION_INFO_CAP_SPARSE_MMAP, 1);
> >> + if (IS_ERR(header))
> >> + return PTR_ERR(header);
> >> +
> >> + sparse_cap = container_of(header,
> >> + struct vfio_region_info_cap_sparse_mmap, header);
> >> + sparse_cap->nr_areas = sparse->nr_areas;
> >> + memcpy(sparse_cap->areas, sparse->areas,
> >> + sparse->nr_areas * sizeof(*sparse->areas));
> >> + return 0;
> >> +}
> >> +
> >> +static int region_type_cap(struct vfio_info_cap *caps, void *cap_type)
> >> +{
> >> + struct vfio_info_cap_header *header;
> >> + struct vfio_region_info_cap_type *type_cap, *cap = cap_type;
> >> +
> >> + header = vfio_info_cap_add(caps, sizeof(*cap),
> >> + VFIO_REGION_INFO_CAP_TYPE, 1);
> >> + if (IS_ERR(header))
> >> + return PTR_ERR(header);
> >> +
> >> + type_cap = container_of(header, struct vfio_region_info_cap_type,
> >> + header);
> >> + type_cap->type = cap->type;
> >> + type_cap->subtype = cap->subtype;
> >> + return 0;
> >> +}
> >> +
> >> +int vfio_info_add_capability(struct vfio_info_cap *caps, int cap_type_id,
> >> + void *cap_type)
> >> +{
> >> + int ret = -EINVAL;
> >> +
> >> + if (!cap_type)
> >> + return 0;
> >> +
> >> + switch (cap_type_id) {
> >> + case VFIO_REGION_INFO_CAP_SPARSE_MMAP:
> >> + ret = sparse_mmap_cap(caps, cap_type);
> >> + break;
> >> +
> >> + case VFIO_REGION_INFO_CAP_TYPE:
> >> + ret = region_type_cap(caps, cap_type);
> >> + break;
> >> + }
> >> +
> >> + return ret;
> >> +}
> >> +EXPORT_SYMBOL(vfio_info_add_capability);
> >>
> >> /*
> >> * Pin a set of guest PFNs and return their associated host PFNs for local
> >> diff --git a/include/linux/vfio.h b/include/linux/vfio.h
> >> index dcda8fccefab..cf90393a11e2 100644
> >> --- a/include/linux/vfio.h
> >> +++ b/include/linux/vfio.h
> >> @@ -113,6 +113,9 @@ extern struct vfio_info_cap_header *vfio_info_cap_add(
> >> struct vfio_info_cap *caps, size_t size, u16 id, u16 version);
> >> extern void vfio_info_cap_shift(struct vfio_info_cap *caps, size_t offset);
> >>
> >> +extern int vfio_info_add_capability(struct vfio_info_cap *caps,
> >> + int cap_type_id, void *cap_type);
> >> +
> >
> >
> > It would make it easier to review and bisect if 14/22 was squashed into
> > this one.
>
> This was split based on Alex's suggestion on earlier version of this
> patchset.
Yeah, generally squashing patches together is the opposite of what we
want for review and bisect. In this case the symbol exports should
avoid any defined-but-unused warnings. Thanks,
Alex
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