Message-ID: <20211210221813.250049810@linutronix.de>
From:   Thomas Gleixner <tglx@linutronix.de>
To:     LKML <linux-kernel@vger.kernel.org>
Cc:     Bjorn Helgaas <helgaas@kernel.org>, Marc Zygnier <maz@kernel.org>,
        Alex Williamson <alex.williamson@redhat.com>,
        Kevin Tian <kevin.tian@intel.com>,
        Jason Gunthorpe <jgg@nvidia.com>,
        Megha Dey <megha.dey@intel.com>,
        Ashok Raj <ashok.raj@intel.com>, linux-pci@vger.kernel.org,
        Cedric Le Goater <clg@kaod.org>,
        Juergen Gross <jgross@suse.com>,
        xen-devel@lists.xenproject.org, Arnd Bergmann <arnd@arndb.de>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        linuxppc-dev@lists.ozlabs.org,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Stuart Yoder <stuyoder@gmail.com>,
        Laurentiu Tudor <laurentiu.tudor@nxp.com>,
        Nishanth Menon <nm@ti.com>, Tero Kristo <kristo@kernel.org>,
        Santosh Shilimkar <ssantosh@kernel.org>,
        linux-arm-kernel@lists.infradead.org,
        Vinod Koul <vkoul@kernel.org>, dmaengine@vger.kernel.org,
        Mark Rutland <mark.rutland@arm.com>,
        Will Deacon <will@kernel.org>,
        Robin Murphy <robin.murphy@arm.com>,
        Joerg Roedel <joro@8bytes.org>,
        iommu@lists.linux-foundation.org,
        Jassi Brar <jassisinghbrar@gmail.com>,
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        Sinan Kaya <okaya@kernel.org>
Subject: [patch V3 01/35] PCI/MSI: Set pci_dev::msi[x]_enabled early
References: <20211210221642.869015045@linutronix.de>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Date:   Fri, 10 Dec 2021 23:18:44 +0100 (CET)
Precedence: bulk

There are quite some places which retrieve the first MSI descriptor to
evaluate whether the setup is for MSI or MSI-X. That's required because
pci_dev::msi[x]_enabled is only set when the setup completed successfully.

There is no real reason why msi[x]_enabled can't be set at the beginning of
the setup sequence and cleared in case of a failure.

Implement that so the MSI descriptor evaluations can be converted to simple
property queries.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
V3: New patch
---
 drivers/pci/msi/msi.c |   23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)

--- a/drivers/pci/msi/msi.c
+++ b/drivers/pci/msi/msi.c
@@ -421,11 +421,18 @@ static int msi_capability_init(struct pc
 	struct msi_desc *entry;
 	int ret;
 
-	pci_msi_set_enable(dev, 0);	/* Disable MSI during set up */
+	/*
+	 * Disable MSI during setup in the hardware, but mark it enabled
+	 * so that setup code can evaluate it.
+	 */
+	pci_msi_set_enable(dev, 0);
+	dev->msi_enabled = 1;
 
 	entry = msi_setup_entry(dev, nvec, affd);
-	if (!entry)
-		return -ENOMEM;
+	if (!entry) {
+		ret = -ENOMEM;
+		goto fail;
+	}
 
 	/* All MSIs are unmasked by default; mask them all */
 	pci_msi_mask(entry, msi_multi_mask(entry));
@@ -452,7 +459,6 @@ static int msi_capability_init(struct pc
 	/* Set MSI enabled bits	*/
 	pci_intx_for_msi(dev, 0);
 	pci_msi_set_enable(dev, 1);
-	dev->msi_enabled = 1;
 
 	pcibios_free_irq(dev);
 	dev->irq = entry->irq;
@@ -461,6 +467,8 @@ static int msi_capability_init(struct pc
 err:
 	pci_msi_unmask(entry, msi_multi_mask(entry));
 	free_msi_irqs(dev);
+fail:
+	dev->msi_enabled = 0;
 	return ret;
 }
 
@@ -589,6 +597,9 @@ static int msix_capability_init(struct p
 	pci_msix_clear_and_set_ctrl(dev, 0, PCI_MSIX_FLAGS_MASKALL |
 				    PCI_MSIX_FLAGS_ENABLE);
 
+	/* Mark it enabled so setup functions can query it */
+	dev->msix_enabled = 1;
+
 	pci_read_config_word(dev, dev->msix_cap + PCI_MSIX_FLAGS, &control);
 	/* Request & Map MSI-X table region */
 	tsize = msix_table_size(control);
@@ -626,9 +637,8 @@ static int msix_capability_init(struct p
 
 	dev->msi_irq_groups = groups;
 
-	/* Set MSI-X enabled bits and unmask the function */
+	/* Disable INTX and unmask MSI-X */
 	pci_intx_for_msi(dev, 0);
-	dev->msix_enabled = 1;
 	pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_MASKALL, 0);
 
 	pcibios_free_irq(dev);
@@ -638,6 +648,7 @@ static int msix_capability_init(struct p
 	free_msi_irqs(dev);
 
 out_disable:
+	dev->msix_enabled = 0;
 	pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_ENABLE, 0);
 
 	return ret;