linux-kernel - [PATCH v4 4/5] net: mana: Allow irq_setup() to skip cpus for affinity

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1748361524-25653-1-git-send-email-shradhagupta@linux.microsoft.com>
Date: Tue, 27 May 2025 08:58:44 -0700
From: Shradha Gupta <shradhagupta@...ux.microsoft.com>
To: Dexuan Cui <decui@...rosoft.com>,
	Wei Liu <wei.liu@...nel.org>,
	Haiyang Zhang <haiyangz@...rosoft.com>,
	"K. Y. Srinivasan" <kys@...rosoft.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>,
	Konstantin Taranov <kotaranov@...rosoft.com>,
	Simon Horman <horms@...nel.org>,
	Leon Romanovsky <leon@...nel.org>,
	Maxim Levitsky <mlevitsk@...hat.com>,
	Erni Sri Satya Vennela <ernis@...ux.microsoft.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Michael Kelley <mhklinux@...look.com>
Cc: Shradha Gupta <shradhagupta@...ux.microsoft.com>,
	linux-hyperv@...r.kernel.org,
	linux-pci@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Nipun Gupta <nipun.gupta@....com>,
	Yury Norov <yury.norov@...il.com>,
	Jason Gunthorpe <jgg@...pe.ca>,
	Jonathan Cameron <Jonathan.Cameron@...ei.com>,
	Anna-Maria Behnsen <anna-maria@...utronix.de>,
	Kevin Tian <kevin.tian@...el.com>,
	Long Li <longli@...rosoft.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	Rob Herring <robh@...nel.org>,
	Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>,
	Krzysztof Wilczy�~Dski <kw@...ux.com>,
	Lorenzo Pieralisi <lpieralisi@...nel.org>,
	netdev@...r.kernel.org,
	linux-rdma@...r.kernel.org,
	Paul Rosswurm <paulros@...rosoft.com>,
	Shradha Gupta <shradhagupta@...rosoft.com>
Subject: [PATCH v4 4/5] net: mana: Allow irq_setup() to skip cpus for affinity

In order to prepare the MANA driver to allocate the MSI-X IRQs
dynamically, we need to enhance irq_setup() to allow skipping
affinitizing IRQs to the first CPU sibling group.

This would be for cases when the number of IRQs is less than or equal
to the number of online CPUs. In such cases for dynamically added IRQs
the first CPU sibling group would already be affinitized with HWC IRQ.

Signed-off-by: Shradha Gupta <shradhagupta@...ux.microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@...rosoft.com>
Reviewed-by: Yury Norov [NVIDIA] <yury.norov@...il.com>
---
 Changes in v4
 * fix commit description
 * avoided using next_cpumask: label in the irq_setup()
---
 drivers/net/ethernet/microsoft/mana/gdma_main.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/microsoft/mana/gdma_main.c b/drivers/net/ethernet/microsoft/mana/gdma_main.c
index f9e8d4d1ba3a..763a548c4a2b 100644
--- a/drivers/net/ethernet/microsoft/mana/gdma_main.c
+++ b/drivers/net/ethernet/microsoft/mana/gdma_main.c
@@ -1329,7 +1329,8 @@ void mana_gd_free_res_map(struct gdma_resource *r)
  * do the same thing.
  */
 
-static int irq_setup(unsigned int *irqs, unsigned int len, int node)
+static int irq_setup(unsigned int *irqs, unsigned int len, int node,
+		     bool skip_first_cpu)
 {
 	const struct cpumask *next, *prev = cpu_none_mask;
 	cpumask_var_t cpus __free(free_cpumask_var);
@@ -1344,11 +1345,18 @@ static int irq_setup(unsigned int *irqs, unsigned int len, int node)
 		while (weight > 0) {
 			cpumask_andnot(cpus, next, prev);
 			for_each_cpu(cpu, cpus) {
+				cpumask_andnot(cpus, cpus, topology_sibling_cpumask(cpu));
+				--weight;
+
+				if (unlikely(skip_first_cpu)) {
+					skip_first_cpu = false;
+					continue;
+				}
+
 				if (len-- == 0)
 					goto done;
+
 				irq_set_affinity_and_hint(*irqs++, topology_sibling_cpumask(cpu));
-				cpumask_andnot(cpus, cpus, topology_sibling_cpumask(cpu));
-				--weight;
 			}
 		}
 		prev = next;
@@ -1444,7 +1452,7 @@ static int mana_gd_setup_irqs(struct pci_dev *pdev)
 		}
 	}
 
-	err = irq_setup(irqs, (nvec - start_irq_index), gc->numa_node);
+	err = irq_setup(irqs, nvec - start_irq_index, gc->numa_node, false);
 	if (err)
 		goto free_irq;
 
-- 
2.34.1