kernel/linux.git/drivers/s390/net, branch v5.9.12

s390/qeth: fix tear down of async TX buffers

2020-12-02T07:51:55+00:00

[ Upstream commit 7ed10e16e50daf74460f54bc922e27c6863c8d61 ] When qeth_iqd_tx_complete() detects that a TX buffer requires additional async completion via QAOB, it might fail to replace the queue entry's metadata (and ends up triggering recovery). Assume now that the device gets torn down, overruling the recovery. If the QAOB notification then arrives before the tear down has sufficiently progressed, the buffer state is changed to QETH_QDIO_BUF_HANDLED_DELAYED by qeth_qdio_handle_aob(). The tear down code calls qeth_drain_output_queue(), where qeth_cleanup_handled_pending() will then attempt to replace such a buffer _again_. If it succeeds this time, the buffer ends up dangling in its replacement's ->next_pending list ... where it will never be freed, since there's no further call to qeth_cleanup_handled_pending(). But the second attempt isn't actually needed, we can simply leave the buffer on the queue and re-use it after a potential recovery has completed. The qeth_clear_output_buffer() in qeth_drain_output_queue() will ensure that it's in a clean state again. Fixes: 72861ae792c2 ("qeth: recovery through asynchronous delivery") Signed-off-by: Julian Wiedmann Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

s390/qeth: fix af_iucv notification race

2020-12-02T07:51:55+00:00

[ Upstream commit 8908f36d20d8ba610d3a7d110b3049b5853b9bb1 ] The two expected notification sequences are 1. TX_NOTIFY_PENDING with a subsequent TX_NOTIFY_DELAYED_*, when our TX completion code first observed the pending TX and the QAOB then completes at a later time; or 2. TX_NOTIFY_OK, when qeth_qdio_handle_aob() picked up the QAOB completion before our TX completion code even noticed that the TX was pending. But as qeth_iqd_tx_complete() and qeth_qdio_handle_aob() can run concurrently, we may end up with a race that results in a sequence of TX_NOTIFY_DELAYED_* followed by TX_NOTIFY_PENDING. Which would confuse the af_iucv code in its tracking of pending transmits. Rework the notification code, so that qeth_qdio_handle_aob() defers its notification if the TX completion code is still active. Fixes: b333293058aa ("qeth: add support for af_iucv HiperSockets transport") Signed-off-by: Julian Wiedmann Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

s390/qeth: make af_iucv TX notification call more robust

2020-12-02T07:51:55+00:00

[ Upstream commit 34c7f50f7d0d36fa663c74aee39e25e912505320 ] Calling into socket code is ugly already, at least check whether we are dealing with the expected sk_family. Only looking at skb->protocol is bound to cause troubles (consider eg. af_packet). Fixes: b333293058aa ("qeth: add support for af_iucv HiperSockets transport") Signed-off-by: Julian Wiedmann Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

s390/qeth: don't let HW override the configured port role

2020-10-29T09:12:21+00:00

[ Upstream commit a04f0ecacdb0639d416614619225a39de3927e22 ] The only time that our Bridgeport role should change is when we change the configuration ourselves. In which case we also adjust our internal state tracking, no need to do it again when we receive the corresponding event. Removing the locked section helps a subsequent patch that needs to flush the workqueue while under sbp_lock. It would be nice to raise a warning here in case HW does weird things after all, but this could end up generating false-positives when we change the configuration ourselves. Suggested-by: Alexandra Winter Signed-off-by: Julian Wiedmann Reviewed-by: Alexandra Winter Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

s390/qeth: strictly order bridge address events

2020-10-29T09:12:19+00:00

[ Upstream commit 9d6a569a4cbab5a8b4c959d4e312daeecb7c9f09 ] The current code for bridge address events has two shortcomings in its control sequence: 1. after disabling address events via PNSO, we don't flush the remaining events from the event_wq. So if the feature is re-enabled fast enough, stale events could leak over. 2. PNSO and the events' arrival via the READ ccw device are unordered. So even if we flushed the workqueue, it's difficult to say whether the READ device might produce more events onto the workqueue afterwards. Fix this by 1. explicitly fencing off the events when we no longer care, in the READ device's event handler. This ensures that once we flush the workqueue, it doesn't get additional address events. 2. Flush the workqueue after disabling the events & fencing them off. As the code that triggers the flush will typically hold the sbp_lock, we need to rework the worker code to avoid a deadlock here in case of a 'notifications-stopped' event. In case of lock contention, requeue such an event with a delay. We'll eventually aquire the lock, or spot that the feature has been disabled and the event can thus be discarded. This leaves the theoretical race that a stale event could arrive _after_ we re-enabled ourselves to receive events again. Such an event would be impossible to distinguish from a 'good' event, nothing we can do about it. Signed-off-by: Julian Wiedmann Reviewed-by: Alexandra Winter Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

s390/qeth: delay draining the TX buffers

2020-09-10T20:31:10+00:00

Wait until the QDIO data connection is severed. Otherwise the device might still be processing the buffers, and end up accessing skb data that we already freed. Fixes: 8b5026bc1693 ("s390/qeth: fix qdio teardown after early init error") Signed-off-by: Julian Wiedmann Signed-off-by: David S. Miller

treewide: Use fallthrough pseudo-keyword

2020-08-23T22:36:59+00:00

Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva

s390/qeth: use all configured RX buffers

2020-07-31T23:44:36+00:00

The (misplaced) comment doesn't make any sense, enforcing an uninitialized RX buffer won't help with IRQ reduction. So make the best use of all available RX buffers. Signed-off-by: Julian Wiedmann Signed-off-by: David S. Miller

s390/qeth: don't process empty bridge port events

2020-07-31T23:44:36+00:00

Discard events that don't contain any entries. This shouldn't happen, but subsequent code relies on being able to use entry 0. So better be safe than accessing garbage. Fixes: b4d72c08b358 ("qeth: bridgeport support - basic control") Signed-off-by: Julian Wiedmann Reviewed-by: Alexandra Winter Signed-off-by: David S. Miller

s390/qeth: integrate RX refill worker with NAPI

2020-07-31T23:44:35+00:00

Running a RX refill outside of NAPI context is inherently racy, even though the worker is only started for an entirely idle RX ring. >From the moment that the worker has replenished parts of the RX ring, the HW can use those RX buffers, raise an IRQ and cause our NAPI code to run concurrently to the RX refill worker. Instead let the worker schedule our NAPI instance, and refill the RX ring from there. Keeping accurate count of how many buffers still need to be refilled also removes some quirky arithmetic from the low-level code. Fixes: b333293058aa ("qeth: add support for af_iucv HiperSockets transport") Signed-off-by: Julian Wiedmann Signed-off-by: David S. Miller