mo...@rodents-montreal.org (Mouse) writes:
>> My question is:
>> Can I use such retrieved file_fd or struct socket* so in separate
>> kernel thread ?
>I see no reason why not - but that is not at all the same as "yes". I
>do not work with multiple threads often enough to feel confident of my
>answer here.
The kernel iSCSI initiator takes a file descriptor from
userland and then uses the socket in two separate threads,
one sending, one receiving.
While the two threads use a rwlock to protect the socket,
they acquire it in shared ("READER") mode for I/O and
in exclusive ("WRITER") mode for closing and replacing
during error recovery.
The socket operations themselves are protected by the
socket lock. In case of PF_INET that's a global lock
(even with NET_MPSAFE). In case of PF_LOCAL, each
socket has a private lock.
