linux-kernel - [patch 08/35] net: e100: Remove in_interrupt() usage and pointless GFP

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Message-Id: <20200927194920.621578351@linutronix.de>
Date:   Sun, 27 Sep 2020 21:48:54 +0200
From:   Thomas Gleixner <tglx@...utronix.de>
To:     LKML <linux-kernel@...r.kernel.org>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        Linus Torvalds <torvalds@...uxfoundation.org>,
        Paul McKenney <paulmck@...nel.org>,
        Matthew Wilcox <willy@...radead.org>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        Jeff Kirsher <jeffrey.t.kirsher@...el.com>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        intel-wired-lan@...ts.osuosl.org, netdev@...r.kernel.org,
        Christian Benvenuti <benve@...co.com>,
        Govindarajulu Varadarajan <_govind@....com>,
        Dave Miller <davem@...emloft.net>,
        Jonathan Corbet <corbet@....net>,
        Mauro Carvalho Chehab <mchehab+huawei@...nel.org>,
        linux-doc@...r.kernel.org,
        Luc Van Oostenryck <luc.vanoostenryck@...il.com>,
        Jay Cliburn <jcliburn@...il.com>,
        Chris Snook <chris.snook@...il.com>,
        Vishal Kulkarni <vishal@...lsio.com>,
        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 08/35] net: e100: Remove in_interrupt() usage and pointless
 GFP_ATOMIC allocation

From: Sebastian Andrzej Siewior <bigeasy@...utronix.de>

e100_hw_init() invokes e100_self_test() only if in_interrupt() returns
false as e100_self_test() uses msleep() which requires sleepable task
context. The in_interrupt() check is incomplete because in_interrupt()
cannot catch callers from contexts which have just preemption or interrupts
disabled.

e100_hw_init() is invoked from:

  - e100_loopback_test() which clearly is sleepable task context as the
    function uses msleep() itself.

  - e100_up() which clearly is sleepable task context as well because it
    invokes e100_alloc_cbs() abd request_irq() which both require sleepable
    task context due to GFP_KERNEL allocations and mutex_lock() operations.

Remove the pointless in_interrupt() check.

As a side effect of this analysis it turned out that e100_rx_alloc_list()
which is only invoked from e100_loopback_test() and e100_up() pointlessly
uses a GFP_ATOMIC allocation. The next invoked function e100_alloc_cbs() is
using GFP_KERNEL already.

Change the allocation mode in e100_rx_alloc_list() to GFP_KERNEL as well.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: Jeff Kirsher <jeffrey.t.kirsher@...el.com>
Cc: "David S. Miller" <davem@...emloft.net>
Cc: Jakub Kicinski <kuba@...nel.org>
Cc: intel-wired-lan@...ts.osuosl.org
Cc: netdev@...r.kernel.org

---
 drivers/net/ethernet/intel/e100.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/net/ethernet/intel/e100.c
+++ b/drivers/net/ethernet/intel/e100.c
@@ -1531,7 +1531,7 @@ static int e100_hw_init(struct nic *nic)
 	e100_hw_reset(nic);
 
 	netif_err(nic, hw, nic->netdev, "e100_hw_init\n");
-	if (!in_interrupt() && (err = e100_self_test(nic)))
+	if ((err = e100_self_test(nic)))
 		return err;
 
 	if ((err = e100_phy_init(nic)))
@@ -2155,7 +2155,7 @@ static int e100_rx_alloc_list(struct nic
 	nic->rx_to_use = nic->rx_to_clean = NULL;
 	nic->ru_running = RU_UNINITIALIZED;
 
-	if (!(nic->rxs = kcalloc(count, sizeof(struct rx), GFP_ATOMIC)))
+	if (!(nic->rxs = kcalloc(count, sizeof(struct rx), GFP_KERNEL)))
 		return -ENOMEM;
 
 	for (rx = nic->rxs, i = 0; i < count; rx++, i++) {