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Subject[tip: irq/msi] PCI/MSI: Set pci_dev::msi[x]_enabled early
The following commit has been merged into the irq/msi branch of tip:

Commit-ID: c7ecb95ca6a80b29af0f41cc28c58e542637fbc6
Gitweb: https://git.kernel.org/tip/c7ecb95ca6a80b29af0f41cc28c58e542637fbc6
Author: Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Fri, 10 Dec 2021 23:18:44 +01:00
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Thu, 16 Dec 2021 22:16:37 +01:00

PCI/MSI: Set pci_dev::msi[x]_enabled early

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>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Nishanth Menon <nm@ti.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20211210221813.250049810@linutronix.de

---
drivers/pci/msi/msi.c | 23 +++++++++++++++++------
1 file changed, 17 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/msi/msi.c b/drivers/pci/msi/msi.c
index eb917fe..5af8d9b 100644
--- a/drivers/pci/msi/msi.c
+++ b/drivers/pci/msi/msi.c
@@ -421,11 +421,18 @@ static int msi_capability_init(struct pci_dev *dev, int nvec,
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 pci_dev *dev, int nvec,
/* 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 pci_dev *dev, int nvec,
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 pci_dev *dev, struct msix_entry *entries,
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);
@@ -623,9 +634,8 @@ static int msix_capability_init(struct pci_dev *dev, struct msix_entry *entries,

dev->msi_irq_groups = groups;

- /* Set MSI-X enabled bits and unmask the function */
+ /* Disable INTX */
pci_intx_for_msi(dev, 0);
- dev->msix_enabled = 1;

/*
* Ensure that all table entries are masked to prevent
@@ -645,6 +655,7 @@ out_free:
free_msi_irqs(dev);

out_disable:
+ dev->msix_enabled = 0;
pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_MASKALL | PCI_MSIX_FLAGS_ENABLE, 0);

return ret;
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