From patchwork Tue Sep 29 20:25:24 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Gleixner X-Patchwork-Id: 11806873 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 41F36618 for ; Tue, 29 Sep 2020 20:39:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1C9E82074B for ; Tue, 29 Sep 2020 20:39:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="GxWZdTII"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="CyXJ7UyY" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729603AbgI2Ujm (ORCPT ); Tue, 29 Sep 2020 16:39:42 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:49174 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729417AbgI2UgA (ORCPT ); Tue, 29 Sep 2020 16:36:00 -0400 Message-Id: <20200929203500.979315007@linutronix.de> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1601411757; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: references:references; bh=p8noynpUYoUVoCA3AcE8IXexBkfCyLsxGEPrAE+AsI4=; b=GxWZdTIIqHgC4sHF/8+MlpMTpyE+Ys7tQM9ClxFYteeOzpdW9CUV+RfZQVpPshQ3Jab8uF VwiNSF1l+v37TyOEY0oLQ1Mg3WesnhOVDP4eOsDsAcBRO1CSdyL+HeQVl2qEEE0ZPmurlk mKSrHiTvvwoUUrs5H3BmGYzLfYENz7JzMWcY7ns6CZKAkEtFM1xIL8z67wRo57YMJHSeEL 9foUpmZNYtmQKmUriWGskXls5938ymTN43trd/XooNNNzixOQUY9vxDqYaInxzFmlXyrKF /IpsVlVqLnsucsRLF4dHfWjutANDXz4i/LF4lPR/sjWVffc1CNwwAam73IGyRg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1601411757; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: references:references; bh=p8noynpUYoUVoCA3AcE8IXexBkfCyLsxGEPrAE+AsI4=; b=CyXJ7UyYA/JETWPHQnDFpdz/d1SjcViFnqKn1ddsxKPw2C0BkbX2Q7Dvp3KSrmhyLaB6Qq amDNkvL368OqZVAA== Date: Tue, 29 Sep 2020 22:25:24 +0200 From: Thomas Gleixner To: LKML Cc: Peter Zijlstra , Paul McKenney , Matthew Wilcox , Christian Benvenuti , Govindarajulu Varadarajan <_govind@gmx.com>, Dave Miller , Jakub Kicinski , netdev@vger.kernel.org, Jonathan Corbet , Mauro Carvalho Chehab , linux-doc@vger.kernel.org, Sebastian Andrzej Siewior , Luc Van Oostenryck , Jay Cliburn , Chris Snook , Vishal Kulkarni , Jeff Kirsher , intel-wired-lan@lists.osuosl.org, Shannon Nelson , Pensando Drivers , Andrew Lunn , Heiner Kallweit , Russell King , Thomas Bogendoerfer , Solarflare linux maintainers , Edward Cree , Martin Habets , Jon Mason , Daniel Drake , Ulrich Kunitz , Kalle Valo , linux-wireless@vger.kernel.org, linux-usb@vger.kernel.org, Greg Kroah-Hartman , Arend van Spriel , Franky Lin , Hante Meuleman , Chi-Hsien Lin , Wright Feng , brcm80211-dev-list.pdl@broadcom.com, brcm80211-dev-list@cypress.com, Stanislav Yakovlev , Stanislaw Gruszka , Johannes Berg , Emmanuel Grumbach , Luca Coelho , Intel Linux Wireless , Jouni Malinen , Amitkumar Karwar , Ganapathi Bhat , Xinming Hu , libertas-dev@lists.infradead.org, Pascal Terjan , Ping-Ke Shih Subject: [patch V2 15/36] net: sfc: Replace in_interrupt() usage References: <20200929202509.673358734@linutronix.de> MIME-Version: 1.0 Content-transfer-encoding: 8-bit Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org From: Edward Cree 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 Signed-off-by: Edward Cree Signed-off-by: Thomas Gleixner Reviewed-by: Martin Habets --- 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