db65a3aaf2
netlink_dump() allocates skb based on the calculated min_dump_alloc or a per socket max_recvmsg_len. min_alloc_size is maximum space required for any single netdev attributes as calculated by rtnl_calcit(). max_recvmsg_len tracks the user provided buffer to netlink_recvmsg. It is capped at 16KiB. The intention is to avoid small allocations and to minimize the number of calls required to obtain dump information for all net devices. netlink_dump packs as many small messages as could fit within an skb that was sized for the largest single netdev information. The actual space available within an skb is larger than what is requested. It could be much larger and up to near 2x with align to next power of 2 approach. Allowing netlink_dump to use all the space available within the allocated skb increases the buffer size a user has to provide to avoid truncaion (i.e. MSG_TRUNG flag set). It was observed that with many VLANs configured on at least one netdev, a larger buffer of near 64KiB was necessary to avoid "Message truncated" error in "ip link" or "bridge [-c[ompressvlans]] vlan show" when min_alloc_size was only little over 32KiB. This patch trims skb to allocated size in order to allow the user to avoid truncation with more reasonable buffer size. Signed-off-by: Ronen Arad <ronen.arad@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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| .. | ||
| af_netlink.c | ||
| af_netlink.h | ||
| diag.c | ||
| genetlink.c | ||
| Kconfig | ||
| Makefile | ||