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Message-ID: <20241204114229.21452-4-wander@redhat.com>
Date: Wed, 4 Dec 2024 08:42:26 -0300
From: Wander Lairson Costa <wander@...hat.com>
To: Tony Nguyen <anthony.l.nguyen@...el.com>,
Przemek Kitszel <przemyslaw.kitszel@...el.com>,
Andrew Lunn <andrew+netdev@...n.ch>,
"David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>,
Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
Clark Williams <clrkwllms@...nel.org>,
Steven Rostedt <rostedt@...dmis.org>,
Auke Kok <auke-jan.h.kok@...el.com>,
Jeff Garzik <jgarzik@...hat.com>,
intel-wired-lan@...ts.osuosl.org (moderated list:INTEL ETHERNET DRIVERS),
netdev@...r.kernel.org (open list:NETWORKING DRIVERS),
linux-kernel@...r.kernel.org (open list),
linux-rt-devel@...ts.linux.dev (open list:Real-time Linux (PREEMPT_RT):Keyword:PREEMPT_RT)
Cc: Wander Lairson Costa <wander@...hat.com>
Subject: [PATCH iwl-net 3/4] igb: split igb_msg_task()
>From the perspective of PREEMPT_RT, igb_msg_task() invokes functions
that are a mix of IRQ-safe and non-IRQ-safe operations.
To address this, we separate igb_msg_task() into distinct IRQ-safe and
preemptible-safe components. This is a preparatory step for upcoming
commits, where the igb_msix_other interrupt handler will be split into
IRQ and threaded handlers, each invoking the appropriate part of the
newly divided igb_msg_task().
Signed-off-by: Wander Lairson Costa <wander@...hat.com>
---
drivers/net/ethernet/intel/igb/igb_main.c | 88 +++++++++++++++++++++--
1 file changed, 81 insertions(+), 7 deletions(-)
diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index 9b4235ec226df..5828831fd29c2 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -149,6 +149,8 @@ static int igb_vlan_rx_kill_vid(struct net_device *, __be16, u16);
static void igb_restore_vlan(struct igb_adapter *);
static void igb_rar_set_index(struct igb_adapter *, u32);
static void igb_ping_all_vfs(struct igb_adapter *);
+static void igb_msg_task_irq_safe(struct igb_adapter *adapter);
+static void igb_msg_task_preemptible_safe(struct igb_adapter *adapter);
static void igb_msg_task(struct igb_adapter *);
static void igb_vmm_control(struct igb_adapter *);
static int igb_set_vf_mac(struct igb_adapter *, int, unsigned char *);
@@ -3681,6 +3683,30 @@ static __always_inline void vfs_unlock_irqrestore(struct igb_adapter *adapter,
raw_spin_unlock_irqrestore(&adapter->raw_vfs_lock, flags);
spin_unlock_irqrestore(&adapter->vfs_lock, flags);
}
+
+static __always_inline void vfs_spin_lock_irqsave(struct igb_adapter *adapter,
+ unsigned long *flags)
+{
+ spin_lock_irqsave(&adapter->vfs_lock, *flags);
+}
+
+static __always_inline void vfs_spin_unlock_irqrestore(struct igb_adapter *adapter,
+ unsigned long flags)
+{
+ spin_unlock_irqrestore(&adapter->vfs_lock, flags);
+}
+
+static __always_inline void vfs_raw_spin_lock_irqsave(struct igb_adapter *adapter,
+ unsigned long *flags)
+{
+ raw_spin_lock_irqsave(&adapter->raw_vfs_lock, *flags);
+}
+
+static __always_inline void vfs_raw_spin_unlock_irqrestore(struct igb_adapter *adapter,
+ unsigned long flags)
+{
+ raw_spin_unlock_irqrestore(&adapter->raw_vfs_lock, flags);
+}
#else
static __always_inline void vfs_lock_init(struct igb_adapter *adapter)
{
@@ -3696,6 +3722,30 @@ static __always_inline void vfs_unlock_irqrestore(struct igb_adapter *adapter, u
{
spin_unlock_irqrestore(&adapter->vfs_lock, flags);
}
+
+static __always_inline void vfs_spin_lock_irqsave(struct igb_adapter *adapter,
+ unsigned long *flags)
+{
+ spin_lock_irqsave(&adapter->vfs_lock, *flags);
+}
+
+static __always_inline void vfs_spin_unlock_irqrestore(struct igb_adapter *adapter,
+ unsigned long flags)
+{
+ spin_unlock_irqrestore(&adapter->vfs_lock, flags);
+}
+
+static __always_inline void vfs_raw_spin_lock_irqsave(struct igb_adapter *adapter,
+ unsigned long *flags)
+{
+ spin_lock_irqsave(&adapter->vfs_lock, *flags);
+}
+
+static __always_inline void vfs_raw_spin_unlock_irqrestore(struct igb_adapter *adapter,
+ unsigned long flags)
+{
+ spin_unlock_irqrestore(&adapter->vfs_lock, flags);
+}
#endif
#ifdef CONFIG_PCI_IOV
@@ -8070,27 +8120,51 @@ static void igb_rcv_msg_from_vf(struct igb_adapter *adapter, u32 vf)
igb_unlock_mbx(hw, vf);
}
-static void igb_msg_task(struct igb_adapter *adapter)
+/*
+ * Note: the split of irq and preempible safe parts of igb_msg_task()
+ * only makes sense under PREEMPT_RT.
+ * The root cause of igb_rcv_msg_from_vf() is not IRQ safe is because
+ * it calls kcalloc with GFP_ATOMIC, but GFP_ATOMIC is not IRQ safe
+ * in PREEMPT_RT.
+ */
+static void igb_msg_task_irq_safe(struct igb_adapter *adapter)
{
struct e1000_hw *hw = &adapter->hw;
unsigned long flags;
u32 vf;
- vfs_lock_irqsave(adapter, &flags);
+ vfs_raw_spin_lock_irqsave(adapter, &flags);
for (vf = 0; vf < adapter->vfs_allocated_count; vf++) {
/* process any reset requests */
if (!igb_check_for_rst(hw, vf))
igb_vf_reset_event(adapter, vf);
- /* process any messages pending */
- if (!igb_check_for_msg(hw, vf))
- igb_rcv_msg_from_vf(adapter, vf);
-
/* process any acks */
if (!igb_check_for_ack(hw, vf))
igb_rcv_ack_from_vf(adapter, vf);
}
- vfs_unlock_irqrestore(adapter, flags);
+ vfs_raw_spin_unlock_irqrestore(adapter, flags);
+}
+
+static void igb_msg_task_preemptible_safe(struct igb_adapter *adapter)
+{
+ struct e1000_hw *hw = &adapter->hw;
+ unsigned long flags;
+ u32 vf;
+
+ vfs_spin_lock_irqsave(adapter, &flags);
+ for (vf = 0; vf < adapter->vfs_allocated_count; vf++) {
+ /* process any messages pending */
+ if (!igb_check_for_msg(hw, vf))
+ igb_rcv_msg_from_vf(adapter, vf);
+ }
+ vfs_spin_unlock_irqrestore(adapter, flags);
+}
+
+static __always_inline void igb_msg_task(struct igb_adapter *adapter)
+{
+ igb_msg_task_irq_safe(adapter);
+ igb_msg_task_preemptible_safe(adapter);
}
/**
--
2.47.0
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