linux-kernel - [patch V4 09/14] PCI/MSI: Switch msix_capability_init() to guard(msi_desc

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Message-ID: <20250319105506.564105011@linutronix.de>
Date: Wed, 19 Mar 2025 11:56:54 +0100 (CET)
From: Thomas Gleixner <tglx@...utronix.de>
To: LKML <linux-kernel@...r.kernel.org>
Cc: Marc Zyngier <maz@...nel.org>,
 Peter Zijlstra <peterz@...radead.org>,
 Jonathan Cameron <Jonathan.Cameron@...wei.com>,
 Nishanth Menon <nm@...com>,
 Dhruva Gole <d-gole@...com>,
 Tero Kristo <kristo@...nel.org>,
 Santosh Shilimkar <ssantosh@...nel.org>,
 Logan Gunthorpe <logang@...tatee.com>,
 Dave Jiang <dave.jiang@...el.com>,
 Jon Mason <jdmason@...zu.us>,
 Allen Hubbe <allenbh@...il.com>,
 ntb@...ts.linux.dev,
 Michael Kelley <mhklinux@...look.com>,
 Wei Liu <wei.liu@...nel.org>,
 Bjorn Helgaas <bhelgaas@...gle.com>,
 Haiyang Zhang <haiyangz@...rosoft.com>,
 linux-hyperv@...r.kernel.org,
 linux-pci@...r.kernel.org,
 Wei Huang <wei.huang2@....com>,
 Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>,
 "James E.J. Bottomley" <James.Bottomley@...senPartnership.com>,
 "Martin K. Petersen" <martin.petersen@...cle.com>,
 linux-scsi@...r.kernel.org,
 Jonathan Cameron <Jonathan.Cameron@...ei.com>
Subject: [patch V4 09/14] PCI/MSI: Switch msix_capability_init() to
 guard(msi_desc_lock)

Split the lock protected functionality of msix_capability_init() out into a
helper function and use guard(msi_desc_lock) to replace the lock/unlock
pair.

Simplify the error path in the helper function by utilizing a custom
cleanup to get rid of the remaining gotos.

No functional change intended.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
---
V4: Split out from the previous combo patch
---
 drivers/pci/msi/msi.c |   36 ++++++++++++++++++++----------------
 1 file changed, 20 insertions(+), 16 deletions(-)

--- a/drivers/pci/msi/msi.c
+++ b/drivers/pci/msi/msi.c
@@ -663,35 +663,39 @@ static void msix_mask_all(void __iomem *
 		writel(ctrl, base + PCI_MSIX_ENTRY_VECTOR_CTRL);
 }

-static int msix_setup_interrupts(struct pci_dev *dev, struct msix_entry *entries,
-				 int nvec, struct irq_affinity *affd)
+DEFINE_FREE(free_msi_irqs, struct pci_dev *, if (_T) pci_free_msi_irqs(_T));
+
+static int __msix_setup_interrupts(struct pci_dev *__dev, struct msix_entry *entries,
+				   int nvec, struct irq_affinity_desc *masks)
 {
-	struct irq_affinity_desc *masks __free(kfree) =
-		affd ? irq_create_affinity_masks(nvec, affd) : NULL;
-	int ret;
+	struct pci_dev *dev __free(free_msi_irqs) = __dev;

-	msi_lock_descs(&dev->dev);
-	ret = msix_setup_msi_descs(dev, entries, nvec, masks);
+	int ret = msix_setup_msi_descs(dev, entries, nvec, masks);
 	if (ret)
-		goto out_free;
+		return ret;

 	ret = pci_msi_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSIX);
 	if (ret)
-		goto out_free;
+		return ret;

 	/* Check if all MSI entries honor device restrictions */
 	ret = msi_verify_entries(dev);
 	if (ret)
-		goto out_free;
+		return ret;

+	retain_ptr(dev);
 	msix_update_entries(dev, entries);
-	goto out_unlock;
+	return 0;
+}
+
+static int msix_setup_interrupts(struct pci_dev *dev, struct msix_entry *entries,
+				 int nvec, struct irq_affinity *affd)
+{
+	struct irq_affinity_desc *masks __free(kfree) =
+		affd ? irq_create_affinity_masks(nvec, affd) : NULL;

-out_free:
-	pci_free_msi_irqs(dev);
-out_unlock:
-	msi_unlock_descs(&dev->dev);
-	return ret;
+	guard(msi_descs_lock)(&dev->dev);
+	return __msix_setup_interrupts(dev, entries, nvec, masks);
 }

 /**