IPoIB: Use netif_tx_lock() and get rid of private tx_lock, LLTX
Currently, IPoIB is an LLTX driver that uses its own IRQ-disabling
tx_lock. Not only do we want to get rid of LLTX, this actually causes
problems because of the skb_orphan() done with this tx_lock held: some
skb destructors expect to be run with interrupts enabled.
The simplest fix for this is to get rid of the driver-private tx_lock
and stop using LLTX. We kill off priv->tx_lock and use
netif_tx_lock[_bh]() instead; the patch to do this is a tiny bit
tricky because we need to update places that take priv->lock inside
the tx_lock to disable IRQs, rather than relying on tx_lock having
already disabled IRQs.
Also, there are a couple of places where we need to disable BHs to
make sure we have a consistent context to call netif_tx_lock() (since
we no longer can use _irqsave() variants), and we also have to change
ipoib_send_comp_handler() to call drain_tx_cq() through a timer rather
than directly, because ipoib_send_comp_handler() runs in interrupt
context and drain_tx_cq() must run in BH context so it can call
netif_tx_lock().
Signed-off-by: Roland Dreier <rolandd@cisco.com>
diff --git a/drivers/infiniband/ulp/ipoib/ipoib.h b/drivers/infiniband/ulp/ipoib/ipoib.h
index 05eb41b..68ba5c3 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib.h
+++ b/drivers/infiniband/ulp/ipoib/ipoib.h
@@ -268,10 +268,9 @@
};
/*
- * Device private locking: tx_lock protects members used in TX fast
- * path (and we use LLTX so upper layers don't do extra locking).
- * lock protects everything else. lock nests inside of tx_lock (ie
- * tx_lock must be acquired first if needed).
+ * Device private locking: network stack tx_lock protects members used
+ * in TX fast path, lock protects everything else. lock nests inside
+ * of tx_lock (ie tx_lock must be acquired first if needed).
*/
struct ipoib_dev_priv {
spinlock_t lock;
@@ -320,7 +319,6 @@
struct ipoib_rx_buf *rx_ring;
- spinlock_t tx_lock;
struct ipoib_tx_buf *tx_ring;
unsigned tx_head;
unsigned tx_tail;