On Thu, Aug 09, 2018 at 08:10:33AM -0600, Jason Gunthorpe wrote: > On Thu, Aug 09, 2018 at 12:54:00PM +0000, Ruhl, Michael J wrote: > > >From: linux-rdma-owner@xxxxxxxxxxxxxxx [mailto:linux-rdma- > > >owner@xxxxxxxxxxxxxxx] On Behalf Of Jason Gunthorpe > > >Sent: Thursday, July 26, 2018 6:37 PM > > >To: linux-rdma@xxxxxxxxxxxxxxx; Leon Romanovsky <leonro@xxxxxxxxxxxx> > > >Subject: [PATCH v3] IB/uverbs: Add UVERBS_ATTR_FLAGS_IN to the specs > > >language > > > > > >This clearly indicates that the input is a bitwise combination of values > > >in an enum, and identifies which enum contains the definition of the bits. > > > > > >Special accessors are provided that handle the mandatory validation of the > > >allowed bits and enforce the correct type for bitwise flags. > > > > > >If we had introduced this at the start then the kabi would have uniformly > > >used u64 data to pass flags, however today there is a mixture of u64 and > > >u32 flags. All places are converted to accept both sizes and the accessor > > >fixes it. This allows all existing flags to grow to u64 in future without > > >any hassle. > > > > > >Finally all flags are, by definition, optional. If flags are not passed > > >the accessor does not fail, but provides a value of zero. > > > > > >Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx> > > > drivers/infiniband/core/uverbs_ioctl.c | 51 +++++++++++++++++++ > > > .../core/uverbs_std_types_counters.c | 10 ++-- > > > drivers/infiniband/core/uverbs_std_types_cq.c | 13 +++-- > > > drivers/infiniband/core/uverbs_std_types_mr.c | 10 ++-- > > > drivers/infiniband/hw/mlx5/devx.c | 16 +++--- > > > drivers/infiniband/hw/mlx5/main.c | 16 +++--- > > > include/rdma/uverbs_ioctl.h | 33 ++++++++++++ > > > 7 files changed, 119 insertions(+), 30 deletions(-) > > > > > >- v2 fixes compilation when !CONFIG_INFINIBAND_USER_ACCESS by provding > > > dummy static inline's. > > >- v3 uses BUILD_BUG_ON_ZERO to wrapper the spelling checking sizeof > > > instead of *0 > > > > > >diff --git a/drivers/infiniband/core/uverbs_ioctl.c > > >b/drivers/infiniband/core/uverbs_ioctl.c > > >index db7a92ea5dbe87..23a1777f26e278 100644 > > >+++ b/drivers/infiniband/core/uverbs_ioctl.c > > >@@ -486,3 +486,54 @@ long ib_uverbs_ioctl(struct file *filp, unsigned int > > >cmd, unsigned long arg) > > > > > > return err; > > > } > > >+ > > >+int uverbs_get_flags64(u64 *to, const struct uverbs_attr_bundle > > >*attrs_bundle, > > >+ size_t idx, u64 allowed_bits) > > >+{ > > >+ const struct uverbs_attr *attr; > > >+ u64 flags; > > >+ > > >+ attr = uverbs_attr_get(attrs_bundle, idx); > > >+ /* Missing attribute means 0 flags */ > > >+ if (IS_ERR(attr)) { > > >+ *to = 0; > > >+ return 0; > > >+ } > > >+ > > >+ /* > > >+ * New userspace code should use 8 bytes to pass flags, but we > > >+ * transparently support old userspaces that were using 4 bytes as > > >+ * well. > > >+ */ > > >+ if (attr->ptr_attr.len == 8) > > >+ flags = attr->ptr_attr.data; > > >+ else if (attr->ptr_attr.len == 4) > > >+ memcpy(&flags, &attr->ptr_attr.data, 4); > > > > If you are doing this, can't the top 4 bytes have garbage from the stack? > > Indeed, this was missed during testing apparently. It should read It is my fault, I forgot to send this fix https://git.kernel.org/pub/scm/linux/kernel/git/leon/linux-rdma.git/commit/?h=rdma-next&id=8e675e86808e12b076ec2778a6a455b5833b90e0 > > - memcpy(&flags, &attr->ptr_attr.data, 4); > + flags = *(u32 *)&attr->ptr_attr.data; > > Jason > -- > To unsubscribe from this list: send the line "unsubscribe linux-rdma" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html
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