path: root/net/netfilter
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authorDaniel Borkmann <daniel@iogearbox.net>2015-09-10 01:20:46 +0200
committerDavid S. Miller <davem@davemloft.net>2015-09-09 21:42:51 -0700
commita66e36568e30ed3714c0e3a12bd3b64696343ff5 (patch)
tree31f62f5e6258b1eaf5b7e7deede0dc8466031d17 /net/netfilter
parentf2be053c83ee93888fc09d90df2bded0deb28947 (diff)
netlink, mmap: don't walk rx ring on poll if receive queue non-empty
In case of netlink mmap, there can be situations where received frames have to be placed into the normal receive queue. The ring buffer indicates this through NL_MMAP_STATUS_COPY, so the user is asked to pick them up via recvmsg(2) syscall, and to put the slot back to NL_MMAP_STATUS_UNUSED. Commit 0ef707700f1c ("netlink: rx mmap: fix POLLIN condition") changed polling, so that we walk in the worst case the whole ring through the new netlink_has_valid_frame(), for example, when the ring would have no NL_MMAP_STATUS_VALID, but at least one NL_MMAP_STATUS_COPY frame. Since we do a datagram_poll() already earlier to pick up a mask that could possibly contain POLLIN | POLLRDNORM already (due to NL_MMAP_STATUS_COPY), we can skip checking the rx ring entirely. In case the kernel is compiled with !CONFIG_NETLINK_MMAP, then all this is irrelevant anyway as netlink_poll() is just defined as datagram_poll(). Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/netfilter')
0 files changed, 0 insertions, 0 deletions

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