rds: Make sure updates to cp_send_gen can be observed

cp->cp_send_gen is treated as a normal variable, although it may be
used by different threads.

This is fixed by using {READ,WRITE}_ONCE when it is incremented and
READ_ONCE when it is read outside the {acquire,release}_in_xmit
protection.

Normative reference from the Linux-Kernel Memory Model:

    Loads from and stores to shared (but non-atomic) variables should
    be protected with the READ_ONCE(), WRITE_ONCE(), and
    ACCESS_ONCE().

Clause 5.1.2.4/25 in the C standard is also relevant.

Signed-off-by: Håkon Bugge <[email protected]>
Reviewed-by: Knut Omang <[email protected]>
Acked-by: Santosh Shilimkar <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

0 files changed, 0 insertions, 0 deletions