The branch main has been updated by bz:
URL:
https://cgit.FreeBSD.org/src/commit/?id=ac07a3b8b6ec14059136f87a1aba0bf4e3333361
commit ac07a3b8b6ec14059136f87a1aba0bf4e3333361
Author: Bjoern A. Zeeb <b...@freebsd.org>
AuthorDate: 2022-09-07 23:35:41 +0000
Commit: Bjoern A. Zeeb <b...@freebsd.org>
CommitDate: 2022-09-07 23:35:41 +0000
LinuxKPI: netdev: expose napi state
There are drivers directly accessing napi->state testing for bits
(NAPI_STATE_SCHED encountered so far). Rename the internal _flags
struct field to state and expose our internal state flag bits along
with the one official aliased.
As I left in a comment, I wished Linux would hide these accesses
behind inline functions or by other means and not public expose
the implementation details.
MFC after: 1 week
---
.../linuxkpi/common/include/linux/netdevice.h | 29 ++++++++++-
sys/compat/linuxkpi/common/src/linux_netdev.c | 57 ++++++++++------------
2 files changed, 52 insertions(+), 34 deletions(-)
diff --git a/sys/compat/linuxkpi/common/include/linux/netdevice.h
b/sys/compat/linuxkpi/common/include/linux/netdevice.h
index f8c03f92b025..a904b7e70490 100644
--- a/sys/compat/linuxkpi/common/include/linux/netdevice.h
+++ b/sys/compat/linuxkpi/common/include/linux/netdevice.h
@@ -5,7 +5,7 @@
* Copyright (c) 2013-2019 Mellanox Technologies, Ltd.
* All rights reserved.
* Copyright (c) 2020-2021 The FreeBSD Foundation
- * Copyright (c) 2020-2021 Bjoern A. Zeeb
+ * Copyright (c) 2020-2022 Bjoern A. Zeeb
*
* Portions of this software were developed by Björn Zeeb
* under sponsorship from the FreeBSD Foundation.
@@ -182,6 +182,30 @@ int unregister_inetaddr_notifier(struct
notifier_block *);
#define NAPI_POLL_WEIGHT 64 /* budget */
+/*
+ * There are drivers directly testing napi state bits, so we need to publicly
+ * expose them. If you ask me, those accesses should be hid behind an
+ * inline function and the bit flags not be directly exposed.
+ */
+enum napi_state_bits {
+ /*
+ * Official Linux flags encountered.
+ */
+ NAPI_STATE_SCHED = 1,
+
+ /*
+ * Our internal versions (for now).
+ */
+ /* Do not schedule new things while we are waiting to clear things. */
+ LKPI_NAPI_FLAG_DISABLE_PENDING = 0,
+ /* To synchronise that only one poll is ever running. */
+ LKPI_NAPI_FLAG_IS_SCHEDULED = 1,
+ /* If trying to schedule while poll is running. Need to re-schedule. */
+ LKPI_NAPI_FLAG_LOST_RACE_TRY_AGAIN = 2,
+ /* When shutting down forcefully prevent anything from running
task/poll. */
+ LKPI_NAPI_FLAG_SHUTDOWN = 3,
+};
+
struct napi_struct {
TAILQ_ENTRY(napi_struct) entry;
@@ -191,11 +215,12 @@ struct napi_struct {
int budget;
int rx_count;
+
/*
* These flags mostly need to be checked/changed atomically
* (multiple together in some cases).
*/
- volatile unsigned long _flags;
+ volatile unsigned long state;
/* FreeBSD internal. */
/* Use task for now, so we can easily switch between direct and task. */
diff --git a/sys/compat/linuxkpi/common/src/linux_netdev.c
b/sys/compat/linuxkpi/common/src/linux_netdev.c
index 27e29b40ea44..3055b9c46767 100644
--- a/sys/compat/linuxkpi/common/src/linux_netdev.c
+++ b/sys/compat/linuxkpi/common/src/linux_netdev.c
@@ -1,5 +1,6 @@
/*-
* Copyright (c) 2021 The FreeBSD Foundation
+ * Copyright (c) 2022 Bjoern A. Zeeb
*
* This software was developed by Björn Zeeb under sponsorship from
* the FreeBSD Foundation.
@@ -48,14 +49,6 @@ MALLOC_DEFINE(M_NETDEV, "lkpindev", "Linux KPI netdevice
compat");
#define NAPI_UNLOCK(_ndev) mtx_unlock(&(_ndev)->napi_mtx)
/* --------------------------------------------------------------------------
*/
-/* Do not schedule new things while we are waiting to clear things. */
-#define LKPI_NAPI_FLAG_DISABLE_PENDING 0
-/* To synchronise that only one poll is ever running. */
-#define LKPI_NAPI_FLAG_IS_SCHEDULED 1
-/* If trying to schedule while poll is running. Need to re-schedule. */
-#define LKPI_NAPI_FLAG_LOST_RACE_TRY_AGAIN 2
-/* When shutting down forcefully prevent anything from running task/poll. */
-#define LKPI_NAPI_FLAG_SHUTDOWN 3
#define LKPI_NAPI_FLAGS \
"\20\1DISABLE_PENDING\2IS_SCHEDULED\3LOST_RACE_TRY_AGAIN"
@@ -74,17 +67,17 @@ SYSCTL_INT(_compat_linuxkpi, OID_AUTO, debug_napi,
CTLFLAG_RWTUN,
#define NAPI_TRACE(_n) if (debug_napi & DNAPI_TRACE)
\
printf("NAPI_TRACE %s:%d %u %p (%#jx %b)\n", __func__, __LINE__, \
- (unsigned int)ticks, _n, (uintmax_t)(_n)->_flags, \
- (int)(_n)->_flags, LKPI_NAPI_FLAGS)
+ (unsigned int)ticks, _n, (uintmax_t)(_n)->state, \
+ (int)(_n)->state, LKPI_NAPI_FLAGS)
#define NAPI_TRACE2D(_n, _d) if (debug_napi & DNAPI_TRACE)
\
printf("NAPI_TRACE %s:%d %u %p (%#jx %b) %d\n", __func__, __LINE__, \
- (unsigned int)ticks, _n, (uintmax_t)(_n)->_flags, \
- (int)(_n)->_flags, LKPI_NAPI_FLAGS, _d)
+ (unsigned int)ticks, _n, (uintmax_t)(_n)->state, \
+ (int)(_n)->state, LKPI_NAPI_FLAGS, _d)
#define NAPI_TRACE_TASK(_n, _p, _c) if (debug_napi & DNAPI_TRACE_TASK)
\
printf("NAPI_TRACE %s:%d %u %p (%#jx %b) pending %d count %d " \
"rx_count %d\n", __func__, __LINE__, \
- (unsigned int)ticks, _n, (uintmax_t)(_n)->_flags, \
- (int)(_n)->_flags, LKPI_NAPI_FLAGS, _p, _c, (_n)->rx_count)
+ (unsigned int)ticks, _n, (uintmax_t)(_n)->state, \
+ (int)(_n)->state, LKPI_NAPI_FLAGS, _p, _c, (_n)->rx_count)
#define NAPI_TODO() if (debug_napi & DNAPI_TODO)
\
printf("NAPI_TODO %s:%d %d\n", __func__, __LINE__, ticks)
#define NAPI_IMPROVE() if (debug_napi & DNAPI_IMPROVE)
\
@@ -118,7 +111,7 @@ linuxkpi_napi_schedule_prep(struct napi_struct *napi)
/* Can can only update/return if all flags agree. */
do {
- old = READ_ONCE(napi->_flags);
+ old = READ_ONCE(napi->state);
/* If we are stopping, cannot run again. */
if ((old & BIT(LKPI_NAPI_FLAG_DISABLE_PENDING)) != 0) {
@@ -132,7 +125,7 @@ linuxkpi_napi_schedule_prep(struct napi_struct *napi)
new |= BIT(LKPI_NAPI_FLAG_LOST_RACE_TRY_AGAIN);
new |= BIT(LKPI_NAPI_FLAG_IS_SCHEDULED);
- } while (atomic_cmpset_acq_long(&napi->_flags, old, new) == 0);
+ } while (atomic_cmpset_acq_long(&napi->state, old, new) == 0);
NAPI_TRACE(napi);
return ((old & BIT(LKPI_NAPI_FLAG_IS_SCHEDULED)) == 0);
@@ -157,14 +150,14 @@ again:
goto again;
/* Bandaid for now. */
- if (test_bit(LKPI_NAPI_FLAG_LOST_RACE_TRY_AGAIN, &napi->_flags))
+ if (test_bit(LKPI_NAPI_FLAG_LOST_RACE_TRY_AGAIN, &napi->state))
goto again;
do {
- new = old = READ_ONCE(napi->_flags);
+ new = old = READ_ONCE(napi->state);
clear_bit(LKPI_NAPI_FLAG_LOST_RACE_TRY_AGAIN, &new);
clear_bit(LKPI_NAPI_FLAG_IS_SCHEDULED, &new);
- } while (atomic_cmpset_acq_long(&napi->_flags, old, new) == 0);
+ } while (atomic_cmpset_acq_long(&napi->state, old, new) == 0);
NAPI_TRACE2D(napi, rc);
}
@@ -175,9 +168,9 @@ linuxkpi___napi_schedule(struct napi_struct *napi)
int rc;
NAPI_TRACE(napi);
- if (test_bit(LKPI_NAPI_FLAG_SHUTDOWN, &napi->_flags)) {
- clear_bit(LKPI_NAPI_FLAG_LOST_RACE_TRY_AGAIN, &napi->_flags);
- clear_bit(LKPI_NAPI_FLAG_IS_SCHEDULED, &napi->_flags);
+ if (test_bit(LKPI_NAPI_FLAG_SHUTDOWN, &napi->state)) {
+ clear_bit(LKPI_NAPI_FLAG_LOST_RACE_TRY_AGAIN, &napi->state);
+ clear_bit(LKPI_NAPI_FLAG_IS_SCHEDULED, &napi->state);
NAPI_TRACE(napi);
return;
}
@@ -229,7 +222,7 @@ linuxkpi_napi_complete_done(struct napi_struct *napi, int
ret)
return (true);
do {
- new = old = READ_ONCE(napi->_flags);
+ new = old = READ_ONCE(napi->state);
/*
* If we lost a race before, we need to re-schedule.
@@ -238,7 +231,7 @@ linuxkpi_napi_complete_done(struct napi_struct *napi, int
ret)
if (!test_bit(LKPI_NAPI_FLAG_LOST_RACE_TRY_AGAIN, &old))
clear_bit(LKPI_NAPI_FLAG_IS_SCHEDULED, &new);
clear_bit(LKPI_NAPI_FLAG_LOST_RACE_TRY_AGAIN, &new);
- } while (atomic_cmpset_acq_long(&napi->_flags, old, new) == 0);
+ } while (atomic_cmpset_acq_long(&napi->state, old, new) == 0);
NAPI_TRACE(napi);
@@ -263,10 +256,10 @@ void
linuxkpi_napi_disable(struct napi_struct *napi)
{
NAPI_TRACE(napi);
- set_bit(LKPI_NAPI_FLAG_DISABLE_PENDING, &napi->_flags);
- while (test_bit(LKPI_NAPI_FLAG_IS_SCHEDULED, &napi->_flags))
+ set_bit(LKPI_NAPI_FLAG_DISABLE_PENDING, &napi->state);
+ while (test_bit(LKPI_NAPI_FLAG_IS_SCHEDULED, &napi->state))
pause_sbt("napidslp", SBT_1MS, 0, C_HARDCLOCK);
- clear_bit(LKPI_NAPI_FLAG_DISABLE_PENDING, &napi->_flags);
+ clear_bit(LKPI_NAPI_FLAG_DISABLE_PENDING, &napi->state);
}
void
@@ -274,11 +267,11 @@ linuxkpi_napi_enable(struct napi_struct *napi)
{
NAPI_TRACE(napi);
- KASSERT(!test_bit(LKPI_NAPI_FLAG_IS_SCHEDULED, &napi->_flags),
+ KASSERT(!test_bit(LKPI_NAPI_FLAG_IS_SCHEDULED, &napi->state),
("%s: enabling napi %p already scheduled\n", __func__, napi));
mb();
/* Let us be scheduled. */
- clear_bit(LKPI_NAPI_FLAG_IS_SCHEDULED, &napi->_flags);
+ clear_bit(LKPI_NAPI_FLAG_IS_SCHEDULED, &napi->state);
}
void
@@ -287,7 +280,7 @@ linuxkpi_napi_synchronize(struct napi_struct *napi)
NAPI_TRACE(napi);
#if defined(SMP)
/* Check & sleep while a napi is scheduled. */
- while (test_bit(LKPI_NAPI_FLAG_IS_SCHEDULED, &napi->_flags))
+ while (test_bit(LKPI_NAPI_FLAG_IS_SCHEDULED, &napi->state))
pause_sbt("napisslp", SBT_1MS, 0, C_HARDCLOCK);
#else
mb();
@@ -350,7 +343,7 @@ linuxkpi_netif_napi_add(struct net_device *ndev, struct
napi_struct *napi,
NAPI_UNLOCK(ndev);
/* Anything else to do on the ndev? */
- clear_bit(LKPI_NAPI_FLAG_SHUTDOWN, &napi->_flags);
+ clear_bit(LKPI_NAPI_FLAG_SHUTDOWN, &napi->state);
}
static void
@@ -361,7 +354,7 @@ lkpi_netif_napi_del_locked(struct napi_struct *napi)
ndev = napi->dev;
NAPI_LOCK_ASSERT(ndev);
- set_bit(LKPI_NAPI_FLAG_SHUTDOWN, &napi->_flags);
+ set_bit(LKPI_NAPI_FLAG_SHUTDOWN, &napi->state);
TAILQ_REMOVE(&ndev->napi_head, napi, entry);
while (taskqueue_cancel(ndev->napi_tq, &napi->napi_task, NULL) != 0)
taskqueue_drain(ndev->napi_tq, &napi->napi_task);
