Re: [PATCH v12 net-next 03/11] bpf: add lookup/update/delete/iterate methods to BPF maps
From: David Miller <davem@davemloft.net>
Date: 2014-09-16 19:16:12
Also in:
linux-api, lkml
From: Alexei Starovoitov <redacted> Date: Mon, 15 Sep 2014 12:18:33 -0700
quoted hunk ↗ jump to hunk
@@ -83,6 +112,15 @@ union bpf_attr { __u32 value_size; /* size of value in bytes */ __u32 max_entries; /* max number of entries in a map */ }; + + struct { /* anonymous struct used by BPF_MAP_*_ELEM commands */ + int map_fd; + void __user *key; + union { + void __user *value; + void __user *next_key; + }; + }; }; #endif /* _UAPI__LINUX_BPF_H__ */
Depending upon the processor ABI, this change can increase the alignment requirements of union bpf_attr. So the structure is not compatible between patch #1 and patch #3 here. Also, you haven't implemented any compat layer whatsoever for the necessary translations. This happens because you are using pointers which are different sized between 32-bit and 64-bit ABIs. I would suggest you use instead something like "aligned_u64" since these are just arbitrary userland cookies and using "aligned_u64" vs. "u64" will make it so that you don't have to deal with the 64-bit type alignment differences between x86-32 and x86-64 while writing the compat wrappers (if any).