6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jan Beulich jbeulich@suse.com
commit 7b55984c96ffe9e236eb9c82a2196e0b1f84990d upstream.
Invoking the make_tx_response() / push_tx_responses() pair with no lock held would be acceptable only if all such invocations happened from the same context (NAPI instance or dealloc thread). Since this isn't the case, and since the interface "spec" also doesn't demand that multicast operations may only be performed with no in-flight transmits, MCAST_{ADD,DEL} processing also needs to acquire the response lock around the invocations.
To prevent similar mistakes going forward, "downgrade" the present functions to private helpers of just the two remaining ones using them directly, with no forward declarations anymore. This involves renaming what so far was make_tx_response(), for the new function of that name to serve the new (wrapper) purpose.
While there, - constify the txp parameters, - correct xenvif_idx_release()'s status parameter's type, - rename {,_}make_tx_response()'s status parameters for consistency with xenvif_idx_release()'s.
Fixes: 210c34dcd8d9 ("xen-netback: add support for multicast control") Cc: stable@vger.kernel.org Signed-off-by: Jan Beulich jbeulich@suse.com Reviewed-by: Paul Durrant paul@xen.org Link: https://lore.kernel.org/r/980c6c3d-e10e-4459-8565-e8fbde122f00@suse.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/xen-netback/netback.c | 84 ++++++++++++++++++-------------------- 1 file changed, 40 insertions(+), 44 deletions(-)
--- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -104,13 +104,12 @@ bool provides_xdp_headroom = true; module_param(provides_xdp_headroom, bool, 0644);
static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx, - u8 status); + s8 status);
static void make_tx_response(struct xenvif_queue *queue, - struct xen_netif_tx_request *txp, + const struct xen_netif_tx_request *txp, unsigned int extra_count, - s8 st); -static void push_tx_responses(struct xenvif_queue *queue); + s8 status);
static void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx);
@@ -208,13 +207,9 @@ static void xenvif_tx_err(struct xenvif_ unsigned int extra_count, RING_IDX end) { RING_IDX cons = queue->tx.req_cons; - unsigned long flags;
do { - spin_lock_irqsave(&queue->response_lock, flags); make_tx_response(queue, txp, extra_count, XEN_NETIF_RSP_ERROR); - push_tx_responses(queue); - spin_unlock_irqrestore(&queue->response_lock, flags); if (cons == end) break; RING_COPY_REQUEST(&queue->tx, cons++, txp); @@ -465,12 +460,7 @@ static void xenvif_get_requests(struct x for (shinfo->nr_frags = 0; nr_slots > 0 && shinfo->nr_frags < MAX_SKB_FRAGS; nr_slots--) { if (unlikely(!txp->size)) { - unsigned long flags; - - spin_lock_irqsave(&queue->response_lock, flags); make_tx_response(queue, txp, 0, XEN_NETIF_RSP_OKAY); - push_tx_responses(queue); - spin_unlock_irqrestore(&queue->response_lock, flags); ++txp; continue; } @@ -496,14 +486,8 @@ static void xenvif_get_requests(struct x
for (shinfo->nr_frags = 0; shinfo->nr_frags < nr_slots; ++txp) { if (unlikely(!txp->size)) { - unsigned long flags; - - spin_lock_irqsave(&queue->response_lock, flags); make_tx_response(queue, txp, 0, XEN_NETIF_RSP_OKAY); - push_tx_responses(queue); - spin_unlock_irqrestore(&queue->response_lock, - flags); continue; }
@@ -997,7 +981,6 @@ static void xenvif_tx_build_gops(struct (ret == 0) ? XEN_NETIF_RSP_OKAY : XEN_NETIF_RSP_ERROR); - push_tx_responses(queue); continue; }
@@ -1009,7 +992,6 @@ static void xenvif_tx_build_gops(struct
make_tx_response(queue, &txreq, extra_count, XEN_NETIF_RSP_OKAY); - push_tx_responses(queue); continue; }
@@ -1444,8 +1426,35 @@ int xenvif_tx_action(struct xenvif_queue return work_done; }
+static void _make_tx_response(struct xenvif_queue *queue, + const struct xen_netif_tx_request *txp, + unsigned int extra_count, + s8 status) +{ + RING_IDX i = queue->tx.rsp_prod_pvt; + struct xen_netif_tx_response *resp; + + resp = RING_GET_RESPONSE(&queue->tx, i); + resp->id = txp->id; + resp->status = status; + + while (extra_count-- != 0) + RING_GET_RESPONSE(&queue->tx, ++i)->status = XEN_NETIF_RSP_NULL; + + queue->tx.rsp_prod_pvt = ++i; +} + +static void push_tx_responses(struct xenvif_queue *queue) +{ + int notify; + + RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->tx, notify); + if (notify) + notify_remote_via_irq(queue->tx_irq); +} + static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx, - u8 status) + s8 status) { struct pending_tx_info *pending_tx_info; pending_ring_idx_t index; @@ -1455,8 +1464,8 @@ static void xenvif_idx_release(struct xe
spin_lock_irqsave(&queue->response_lock, flags);
- make_tx_response(queue, &pending_tx_info->req, - pending_tx_info->extra_count, status); + _make_tx_response(queue, &pending_tx_info->req, + pending_tx_info->extra_count, status);
/* Release the pending index before pusing the Tx response so * its available before a new Tx request is pushed by the @@ -1470,32 +1479,19 @@ static void xenvif_idx_release(struct xe spin_unlock_irqrestore(&queue->response_lock, flags); }
- static void make_tx_response(struct xenvif_queue *queue, - struct xen_netif_tx_request *txp, + const struct xen_netif_tx_request *txp, unsigned int extra_count, - s8 st) + s8 status) { - RING_IDX i = queue->tx.rsp_prod_pvt; - struct xen_netif_tx_response *resp; - - resp = RING_GET_RESPONSE(&queue->tx, i); - resp->id = txp->id; - resp->status = st; - - while (extra_count-- != 0) - RING_GET_RESPONSE(&queue->tx, ++i)->status = XEN_NETIF_RSP_NULL; + unsigned long flags;
- queue->tx.rsp_prod_pvt = ++i; -} + spin_lock_irqsave(&queue->response_lock, flags);
-static void push_tx_responses(struct xenvif_queue *queue) -{ - int notify; + _make_tx_response(queue, txp, extra_count, status); + push_tx_responses(queue);
- RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->tx, notify); - if (notify) - notify_remote_via_irq(queue->tx_irq); + spin_unlock_irqrestore(&queue->response_lock, flags); }
static void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx)