On Wed, Jun 13, 2018 at 05:34:03AM -0700, willy@xxxxxxxxxxxxx wrote: > Allocate agent IDs from a global IDR instead of an atomic variable. > This eliminates the possibility of reusing an ID which is already in > use after 4 billion registrations. We limit the assigned ID to be less > than 2^24 as the mlx4 driver uses the most significant byte of the agent > ID to store the slave number. Users unlucky enough to see a collision > between agent numbers and slave numbers see messages like: > > mlx4_ib: egress mad has non-null tid msb:1 class:4 slave:0 > > and the MAD layer stops working. > > We look up the agent under protection of the RCU lock, which means we > have to free the agent using kfree_rcu, and only increment the reference > counter if it is not 0. > > Signed-off-by: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx> > Reported-by: Hans Westgaard Ry <hans.westgaard.ry@xxxxxxxxxx> > Acked-by: Jack Morgenstein <jackm@xxxxxxxxxxxxxxxxxx> > Tested-by: Jack Morgenstein <jackm@xxxxxxxxxxxxxxxxxx> > --- > drivers/infiniband/core/mad.c | 83 ++++++++++++++++++------------ > drivers/infiniband/core/mad_priv.h | 7 +-- > 2 files changed, 55 insertions(+), 35 deletions(-) Applied to for-next, thanks everyone Jason -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
