* Weird locking in __release_sock()?
@ 2011-06-22 23:31 David Daney
2011-06-22 23:42 ` David Miller
0 siblings, 1 reply; 2+ messages in thread
From: David Daney @ 2011-06-22 23:31 UTC (permalink / raw)
To: netdev
Hi,
In net/core/sock.c the function __release_sock() appears to drop the
socket lock, and then feed the backlogged skbs to sk_backlog_rcv().
In the case of an IPv4 TCP socket, sk_backlog_rcv() calls
tcp_v4_do_rcv(), which is documented like this:
/* The socket must have it's spinlock held when we get
* here.
.
.
.
*/
Q: How can this be correct?
Perhaps I am missing something. In any event, thanks in advance
shedding some light on the locking situation.
David Daney
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: Weird locking in __release_sock()?
2011-06-22 23:31 Weird locking in __release_sock()? David Daney
@ 2011-06-22 23:42 ` David Miller
0 siblings, 0 replies; 2+ messages in thread
From: David Miller @ 2011-06-22 23:42 UTC (permalink / raw)
To: ddaney; +Cc: netdev
From: David Daney <ddaney@caviumnetworks.com>
Date: Wed, 22 Jun 2011 16:31:13 -0700
> In the case of an IPv4 TCP socket, sk_backlog_rcv() calls
> tcp_v4_do_rcv(), which is documented like this:
>
> /* The socket must have it's spinlock held when we get
> * here.
> .
> .
> .
> */
>
> Q: How can this be correct?
sk->lock.owned will be "1" while the backlog is processed.
Exclusive access to the socket is indicated by one of the
following two conditions being true:
1) sk->lock.slock being held
2) sk->lock.owned being non-zero
^ permalink raw reply [flat|nested] 2+ messages in thread
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2011-06-22 23:31 Weird locking in __release_sock()? David Daney
2011-06-22 23:42 ` David Miller
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