David Ahern wrote: > On 2/22/18 6:02 AM, Serhey Popovych wrote: >> Now in iplink_parse() we use ->ifi_change and ->ifi_flags fields and >> plan to use ->ifi_index with upcoming change. >> >> Saving, restoring and reinitializing individual fields is error prone: >> using new field in iplink_parse() without updating callers in veth and >> vxcan will overwrite main device ifinfomsg data. >> >> Since @struct ifinfomsg is small enough with known sizeof() compiler may >> inline memcpy()/memset() with few load/store instructions. >> >> Signed-off-by: Serhey Popovych <serhe.popov...@gmail.com> >> --- >> ip/iplink_vxcan.c | 22 ++++++++-------------- >> ip/link_veth.c | 22 ++++++++-------------- >> 2 files changed, 16 insertions(+), 28 deletions(-) > > I don't agree that this change has any benefit. Only the flags and > change field are wanted; there is no need to save the entire struct, >
Struct is small enough, only ifi_change and ifi_flags being used right now, but next patch also changes ifi_index. Remaining values are fit in single u32 (ifi_family, ifi_type and pad). So we copy only one extra u32 at the moment. Later if something gets changed and iplink_parse() starts using ifi_family, ifi_type, ifi_pad... we do not need to modify vxcan and veth modules.
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