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[net-next,0/2] raw: RCU conversion

Message ID 20220617201045.2659460-1-eric.dumazet@gmail.com (mailing list archive)
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Series raw: RCU conversion | expand

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Eric Dumazet June 17, 2022, 8:10 p.m. UTC 
From: Eric Dumazet <edumazet@google.com>

Using rwlock in networking code is extremely risky.
writers can starve if enough readers are constantly
grabing the rwlock.

I thought rwlock were at fault and sent this patch:

https://lkml.org/lkml/2022/6/17/272

But Peter and Linus essentially told me rwlock had to be unfair.

We need to get rid of rwlock in networking stacks.

Without this conversion, following script triggers soft lockups:

for i in {1..48}
do
 ping -f -n -q 127.0.0.1 &
 sleep 0.1
done

Next step will be to convert ping sockets to RCU as well.

Eric Dumazet (2):
  raw: use more conventional iterators
  raw: convert raw sockets to RCU

 include/net/raw.h   |  16 +++--
 include/net/rawv6.h |   7 ++-
 net/ipv4/af_inet.c  |   2 +
 net/ipv4/raw.c      | 150 ++++++++++++++++++--------------------------
 net/ipv4/raw_diag.c |  41 ++++++------
 net/ipv6/af_inet6.c |   3 +
 net/ipv6/raw.c      | 119 +++++++++++++----------------------
 7 files changed, 148 insertions(+), 190 deletions(-)