diff options
Diffstat (limited to 'include/rdma')
| -rw-r--r-- | include/rdma/ib_user_mad.h | 22 |
1 files changed, 21 insertions, 1 deletions
diff --git a/include/rdma/ib_user_mad.h b/include/rdma/ib_user_mad.h index 2a32043d1ab..29d2c7205a9 100644 --- a/include/rdma/ib_user_mad.h +++ b/include/rdma/ib_user_mad.h @@ -147,6 +147,26 @@ struct ib_user_mad { __u64 data[0]; }; +/* + * Earlier versions of this interface definition declared the + * method_mask[] member as an array of __u32 but treated it as a + * bitmap made up of longs in the kernel. This ambiguity meant that + * 32-bit big-endian applications that can run on both 32-bit and + * 64-bit kernels had no consistent ABI to rely on, and 64-bit + * big-endian applications that treated method_mask as being made up + * of 32-bit words would have their bitmap misinterpreted. + * + * To clear up this confusion, we change the declaration of + * method_mask[] to use unsigned long and handle the conversion from + * 32-bit userspace to 64-bit kernel for big-endian systems in the + * compat_ioctl method. Unfortunately, to keep the structure layout + * the same, we need the method_mask[] array to be aligned only to 4 + * bytes even when long is 64 bits, which forces us into this ugly + * typedef. + */ +typedef unsigned long __attribute__((aligned(4))) packed_ulong; +#define IB_USER_MAD_LONGS_PER_METHOD_MASK (128 / (8 * sizeof (long))) + /** * ib_user_mad_reg_req - MAD registration request * @id - Set by the kernel; used to identify agent in future requests. @@ -165,7 +185,7 @@ struct ib_user_mad { */ struct ib_user_mad_reg_req { __u32 id; - __u32 method_mask[4]; + packed_ulong method_mask[IB_USER_MAD_LONGS_PER_METHOD_MASK]; __u8 qpn; __u8 mgmt_class; __u8 mgmt_class_version; |