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Message-Id: <20200929203500.979315007@linutronix.de>
Date: Tue, 29 Sep 2020 22:25:24 +0200
From: Thomas Gleixner <tglx@...utronix.de>
To: LKML <linux-kernel@...r.kernel.org>
Cc: Peter Zijlstra <peterz@...radead.org>,
Paul McKenney <paulmck@...nel.org>,
Matthew Wilcox <willy@...radead.org>,
Christian Benvenuti <benve@...co.com>,
Govindarajulu Varadarajan <_govind@....com>,
Dave Miller <davem@...emloft.net>,
Jakub Kicinski <kuba@...nel.org>, netdev@...r.kernel.org,
Jonathan Corbet <corbet@....net>,
Mauro Carvalho Chehab <mchehab+huawei@...nel.org>,
linux-doc@...r.kernel.org,
Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
Luc Van Oostenryck <luc.vanoostenryck@...il.com>,
Jay Cliburn <jcliburn@...il.com>,
Chris Snook <chris.snook@...il.com>,
Vishal Kulkarni <vishal@...lsio.com>,
Jeff Kirsher <jeffrey.t.kirsher@...el.com>,
intel-wired-lan@...ts.osuosl.org,
Shannon Nelson <snelson@...sando.io>,
Pensando Drivers <drivers@...sando.io>,
Andrew Lunn <andrew@...n.ch>,
Heiner Kallweit <hkallweit1@...il.com>,
Russell King <linux@...linux.org.uk>,
Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
Solarflare linux maintainers <linux-net-drivers@...arflare.com>,
Edward Cree <ecree@...arflare.com>,
Martin Habets <mhabets@...arflare.com>,
Jon Mason <jdmason@...zu.us>, Daniel Drake <dsd@...too.org>,
Ulrich Kunitz <kune@...ne-taler.de>,
Kalle Valo <kvalo@...eaurora.org>,
linux-wireless@...r.kernel.org, linux-usb@...r.kernel.org,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Arend van Spriel <arend.vanspriel@...adcom.com>,
Franky Lin <franky.lin@...adcom.com>,
Hante Meuleman <hante.meuleman@...adcom.com>,
Chi-Hsien Lin <chi-hsien.lin@...ress.com>,
Wright Feng <wright.feng@...ress.com>,
brcm80211-dev-list.pdl@...adcom.com,
brcm80211-dev-list@...ress.com,
Stanislav Yakovlev <stas.yakovlev@...il.com>,
Stanislaw Gruszka <stf_xl@...pl>,
Johannes Berg <johannes.berg@...el.com>,
Emmanuel Grumbach <emmanuel.grumbach@...el.com>,
Luca Coelho <luciano.coelho@...el.com>,
Intel Linux Wireless <linuxwifi@...el.com>,
Jouni Malinen <j@...fi>,
Amitkumar Karwar <amitkarwar@...il.com>,
Ganapathi Bhat <ganapathi.bhat@....com>,
Xinming Hu <huxinming820@...il.com>,
libertas-dev@...ts.infradead.org,
Pascal Terjan <pterjan@...gle.com>,
Ping-Ke Shih <pkshih@...ltek.com>
Subject: [patch V2 15/36] net: sfc: Replace in_interrupt() usage
From: Edward Cree <ecree@...arflare.com>
efx_ef10_try_update_nic_stats_vf() used in_interrupt() to figure out
whether it is safe to sleep (for MCDI) or not.
The only caller from which it was not is efx_net_stats(), which can be
invoked under dev_base_lock from net-sysfs::netstat_show().
So add a new update_stats_atomic() method to struct efx_nic_type, and call
it from efx_net_stats(), removing the need for
efx_ef10_try_update_nic_stats_vf() to behave differently for this case
(which it wasn't doing correctly anyway).
For all nic_types other than EF10 VF, this method is NULL so the the
regular update_stats() methods are invoked , which are happy with being
called from atomic contexts.
Fixes: f00bf2305cab ("sfc: don't update stats on VF when called in atomic context")
Reported-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Signed-off-by: Edward Cree <ecree@...arflare.com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Reviewed-by: Martin Habets <mhabets@...arflare.com>
---
Only compile-tested so far, because I'm waiting for my kernel to
finish rebuilding with CONFIG_DEBUG_ATOMIC_SLEEP which I'm hoping
is the right thing to detect the bug in the existing code.
I also wasn't quite sure how to give credit to the thorough analysis
in the commit message of Sebastian's patch. I don't think we have
a Whatever-by: tag to cover that, do we?
And this doesn't include your GFP_KERNEL change, which should
probably go in separately if you take this.
drivers/net/ethernet/sfc/ef10.c | 22 +++++++++++++---------
drivers/net/ethernet/sfc/efx_common.c | 2 +-
drivers/net/ethernet/sfc/net_driver.h | 5 +++++
drivers/net/ethernet/sfc/nic_common.h | 7 +++++++
4 files changed, 26 insertions(+), 10 deletions(-)
--- a/drivers/net/ethernet/sfc/ef10.c
+++ b/drivers/net/ethernet/sfc/ef10.c
@@ -1871,15 +1871,6 @@ static int efx_ef10_try_update_nic_stats
spin_unlock_bh(&efx->stats_lock);
- if (in_interrupt()) {
- /* If in atomic context, cannot update stats. Just update the
- * software stats and return so the caller can continue.
- */
- spin_lock_bh(&efx->stats_lock);
- efx_update_sw_stats(efx, stats);
- return 0;
- }
-
efx_ef10_get_stat_mask(efx, mask);
rc = efx_nic_alloc_buffer(efx, &stats_buf, dma_len, GFP_ATOMIC);
@@ -1938,6 +1929,18 @@ static size_t efx_ef10_update_stats_vf(s
return efx_ef10_update_stats_common(efx, full_stats, core_stats);
}
+static size_t efx_ef10_update_stats_atomic_vf(struct efx_nic *efx, u64 *full_stats,
+ struct rtnl_link_stats64 *core_stats)
+{
+ struct efx_ef10_nic_data *nic_data = efx->nic_data;
+
+ /* In atomic context, cannot update HW stats. Just update the
+ * software stats and return so the caller can continue.
+ */
+ efx_update_sw_stats(efx, nic_data->stats);
+ return efx_ef10_update_stats_common(efx, full_stats, core_stats);
+}
+
static void efx_ef10_push_irq_moderation(struct efx_channel *channel)
{
struct efx_nic *efx = channel->efx;
@@ -3998,6 +4001,7 @@ const struct efx_nic_type efx_hunt_a0_vf
.finish_flr = efx_port_dummy_op_void,
.describe_stats = efx_ef10_describe_stats,
.update_stats = efx_ef10_update_stats_vf,
+ .update_stats_atomic = efx_ef10_update_stats_atomic_vf,
.start_stats = efx_port_dummy_op_void,
.pull_stats = efx_port_dummy_op_void,
.stop_stats = efx_port_dummy_op_void,
--- a/drivers/net/ethernet/sfc/efx_common.c
+++ b/drivers/net/ethernet/sfc/efx_common.c
@@ -602,7 +602,7 @@ void efx_net_stats(struct net_device *ne
struct efx_nic *efx = netdev_priv(net_dev);
spin_lock_bh(&efx->stats_lock);
- efx->type->update_stats(efx, NULL, stats);
+ efx_nic_update_stats_atomic(efx, NULL, stats);
spin_unlock_bh(&efx->stats_lock);
}
--- a/drivers/net/ethernet/sfc/net_driver.h
+++ b/drivers/net/ethernet/sfc/net_driver.h
@@ -1172,6 +1172,9 @@ struct efx_udp_tunnel {
* @describe_stats: Describe statistics for ethtool
* @update_stats: Update statistics not provided by event handling.
* Either argument may be %NULL.
+ * @update_stats_atomic: Update statistics while in atomic context, if that
+ * is more limiting than @update_stats. Otherwise, leave %NULL and
+ * driver core will call @update_stats.
* @start_stats: Start the regular fetching of statistics
* @pull_stats: Pull stats from the NIC and wait until they arrive.
* @stop_stats: Stop the regular fetching of statistics
@@ -1316,6 +1319,8 @@ struct efx_nic_type {
size_t (*describe_stats)(struct efx_nic *efx, u8 *names);
size_t (*update_stats)(struct efx_nic *efx, u64 *full_stats,
struct rtnl_link_stats64 *core_stats);
+ size_t (*update_stats_atomic)(struct efx_nic *efx, u64 *full_stats,
+ struct rtnl_link_stats64 *core_stats);
void (*start_stats)(struct efx_nic *efx);
void (*pull_stats)(struct efx_nic *efx);
void (*stop_stats)(struct efx_nic *efx);
--- a/drivers/net/ethernet/sfc/nic_common.h
+++ b/drivers/net/ethernet/sfc/nic_common.h
@@ -244,6 +244,13 @@ void efx_nic_update_stats(const struct e
const unsigned long *mask, u64 *stats,
const void *dma_buf, bool accumulate);
void efx_nic_fix_nodesc_drop_stat(struct efx_nic *efx, u64 *stat);
+static inline size_t efx_nic_update_stats_atomic(struct efx_nic *efx, u64 *full_stats,
+ struct rtnl_link_stats64 *core_stats)
+{
+ if (efx->type->update_stats_atomic)
+ return efx->type->update_stats_atomic(efx, full_stats, core_stats);
+ return efx->type->update_stats(efx, full_stats, core_stats);
+}
#define EFX_MAX_FLUSH_TIME 5000
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