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rds: Fix RDMA message reference counting 

The RDS send_xmit code was trying to get fancy with message
counting and was dropping the final reference on the RDMA messages
too early.  This resulted in memory corruption and oopsen.

The fix here is to always add a ref as the parts of the message passes
through rds_send_xmit, and always drop a ref as the parts of the message
go through completion handling.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason 2010-05-11 15:14:16 -07:00 committed by Andy Grover
parent 7e3f2952ee
commit c9e65383a2
2 changed files with 14 additions and 8 deletions
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11
net/rds/ib_send.c
View File

@ -268,11 +268,12 @@ void rds_ib_send_cq_comp_handler(struct ib_cq *cq, void *context)
if (send->s_queued + HZ/2 < jiffies)
rds_ib_stats_inc(s_ib_tx_stalled);
if (&send->s_op == &rm->m_final_op) {
/* If anyone waited for this message to get flushed out, wake
* them up now */
rds_message_unmapped(rm);
if (send->s_op) {
if (send->s_op == rm->m_final_op) {
/* If anyone waited for this message to get flushed out, wake
* them up now */
rds_message_unmapped(rm);
}
rds_message_put(rm);
send->s_op = NULL;
}

11
net/rds/send.c
View File

@ -68,7 +68,6 @@ void rds_send_reset(struct rds_connection *conn)
* transport. This isn't entirely true (it's flushed out
* independently) but as the connection is down, there's
* no ongoing RDMA to/from that memory */
printk(KERN_CRIT "send reset unmapping %p\n", rm);
rds_message_unmapped(rm);
spin_unlock_irqrestore(&conn->c_send_lock, flags);
@ -234,10 +233,13 @@ int rds_send_xmit(struct rds_connection *conn)
/* The transport either sends the whole rdma or none of it */
if (rm->rdma.op_active && !conn->c_xmit_rdma_sent) {
rds_message_addref(rm);
rm->m_final_op = &rm->rdma;
ret = conn->c_trans->xmit_rdma(conn, &rm->rdma);
if (ret)
if (ret) {
rds_message_put(rm);
break;
}
conn->c_xmit_rdma_sent = 1;
/* The transport owns the mapped memory for now.
@ -246,10 +248,13 @@ int rds_send_xmit(struct rds_connection *conn)
}
if (rm->atomic.op_active && !conn->c_xmit_atomic_sent) {
rds_message_addref(rm);
rm->m_final_op = &rm->atomic;
ret = conn->c_trans->xmit_atomic(conn, &rm->atomic);
if (ret)
if (ret) {
rds_message_put(rm);
break;
}
conn->c_xmit_atomic_sent = 1;
/* The transport owns the mapped memory for now.