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Message-ID: <87tuf9rdoj.ffs@tglx>
Date: Wed, 15 Dec 2021 18:16:44 +0100
From: Thomas Gleixner <tglx@...utronix.de>
To: LKML <linux-kernel@...r.kernel.org>
Cc: Bjorn Helgaas <helgaas@...nel.org>, Marc Zygnier <maz@...nel.org>,
Alex Williamson <alex.williamson@...hat.com>,
Kevin Tian <kevin.tian@...el.com>,
Jason Gunthorpe <jgg@...dia.com>,
Megha Dey <megha.dey@...el.com>,
Ashok Raj <ashok.raj@...el.com>, linux-pci@...r.kernel.org,
Cedric Le Goater <clg@...d.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Bjorn Helgaas <bhelgaas@...gle.com>,
Juergen Gross <jgross@...e.com>,
xen-devel@...ts.xenproject.org, Arnd Bergmann <arnd@...db.de>,
Michael Ellerman <mpe@...erman.id.au>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
linuxppc-dev@...ts.ozlabs.org, Stuart Yoder <stuyoder@...il.com>,
Laurentiu Tudor <laurentiu.tudor@....com>,
Nishanth Menon <nm@...com>, Tero Kristo <kristo@...nel.org>,
Santosh Shilimkar <ssantosh@...nel.org>,
linux-arm-kernel@...ts.infradead.org,
Vinod Koul <vkoul@...nel.org>, dmaengine@...r.kernel.org,
Mark Rutland <mark.rutland@....com>,
Will Deacon <will@...nel.org>,
Robin Murphy <robin.murphy@....com>,
Joerg Roedel <joro@...tes.org>,
iommu@...ts.linux-foundation.org,
Jassi Brar <jassisinghbrar@...il.com>,
Peter Ujfalusi <peter.ujfalusi@...il.com>,
Sinan Kaya <okaya@...nel.org>
Subject: [patch V4 09-01/35] PCI/MSI: Decouple MSI[-X] disable from
pcim_release()
The MSI core will introduce runtime allocation of MSI related data. This
data will be devres managed and has to be set up before enabling
PCI/MSI[-X]. This would introduce an ordering issue vs. pcim_release().
The setup order is:
pcim_enable_device()
devres_alloc(pcim_release...);
...
pci_irq_alloc()
msi_setup_device_data()
devres_alloc(msi_device_data_release, ...)
and once the device is released these release functions are invoked in the
opposite order:
msi_device_data_release()
...
pcim_release()
pci_disable_msi[x]()
which is obviously wrong, because pci_disable_msi[x]() requires the MSI
data to be available to tear down the MSI[-X] interrupts.
Remove the MSI[-X] teardown from pcim_release() and add an explicit action
to be installed on the attempt of enabling PCI/MSI[-X].
This allows the MSI core data allocation to be ordered correctly in a
subsequent step.
Reported-by: Nishanth Menon <nm@...com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
---
V4: New patch
---
drivers/pci/msi/msi.c | 33 +++++++++++++++++++++++++++++++++
drivers/pci/pci.c | 5 -----
include/linux/pci.h | 3 ++-
3 files changed, 35 insertions(+), 6 deletions(-)
--- a/drivers/pci/msi/msi.c
+++ b/drivers/pci/msi/msi.c
@@ -341,6 +341,31 @@ void pci_restore_msi_state(struct pci_de
}
EXPORT_SYMBOL_GPL(pci_restore_msi_state);
+static void pcim_msi_release(void *pcidev)
+{
+ struct pci_dev *dev = pcidev;
+
+ dev->is_msi_managed = false;
+ pci_free_irq_vectors(dev);
+}
+
+/*
+ * Needs to be separate from pcim_release to prevent an ordering problem
+ * vs. msi_device_data_release() in the MSI core code.
+ */
+static int pcim_setup_msi_release(struct pci_dev *dev)
+{
+ int ret;
+
+ if (!pci_is_managed(dev) || dev->is_msi_managed)
+ return 0;
+
+ ret = devm_add_action(&dev->dev, pcim_msi_release, dev);
+ if (!ret)
+ dev->is_msi_managed = true;
+ return ret;
+}
+
static struct msi_desc *
msi_setup_entry(struct pci_dev *dev, int nvec, struct irq_affinity *affd)
{
@@ -884,6 +909,10 @@ static int __pci_enable_msi_range(struct
if (nvec > maxvec)
nvec = maxvec;
+ rc = pcim_setup_msi_release(dev);
+ if (rc)
+ return rc;
+
for (;;) {
if (affd) {
nvec = irq_calc_affinity_vectors(minvec, nvec, affd);
@@ -927,6 +956,10 @@ static int __pci_enable_msix_range(struc
if (WARN_ON_ONCE(dev->msix_enabled))
return -EINVAL;
+ rc = pcim_setup_msi_release(dev);
+ if (rc)
+ return rc;
+
for (;;) {
if (affd) {
nvec = irq_calc_affinity_vectors(minvec, nvec, affd);
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -2024,11 +2024,6 @@ static void pcim_release(struct device *
struct pci_devres *this = res;
int i;
- if (dev->msi_enabled)
- pci_disable_msi(dev);
- if (dev->msix_enabled)
- pci_disable_msix(dev);
-
for (i = 0; i < DEVICE_COUNT_RESOURCE; i++)
if (this->region_mask & (1 << i))
pci_release_region(dev, i);
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -425,7 +425,8 @@ struct pci_dev {
unsigned int ats_enabled:1; /* Address Translation Svc */
unsigned int pasid_enabled:1; /* Process Address Space ID */
unsigned int pri_enabled:1; /* Page Request Interface */
- unsigned int is_managed:1;
+ unsigned int is_managed:1; /* Managed via devres */
+ unsigned int is_msi_managed:1; /* MSI release via devres installed */
unsigned int needs_freset:1; /* Requires fundamental reset */
unsigned int state_saved:1;
unsigned int is_physfn:1;
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