Commit 0242132d authored by Naveen Naidu's avatar Naveen Naidu Committed by Bjorn Helgaas
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PCI/DPC: Use PCI_POSSIBLE_ERROR() to check config reads 

When config pci_ops.read() can detect failed PCI transactions, the data
returned to the CPU is PCI_ERROR_RESPONSE (~0 or 0xffffffff).

Obviously a successful PCI config read may *also* return that data if a
config register happens to contain ~0, so it doesn't definitively indicate
an error unless we know the register cannot contain ~0.

Use PCI_POSSIBLE_ERROR() to check the response we get when we read data
from hardware.  This unifies PCI error response checking and makes error
checks consistent and easier to find.

Compile tested only.

Link: https://lore.kernel.org/r/9b0632f1f183432149f495cf12bdd5a72cc597a4.1637243717.git.naveennaidu479@gmail.com


Signed-off-by: default avatarNaveen Naidu <naveennaidu479@gmail.com>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
parent a3b0f10d

drivers/pci/pcie/dpc.c

+2 −2
Original line number Diff line number Diff line
@@ -79,7 +79,7 @@ static bool dpc_completed(struct pci_dev *pdev) 
	u16 status;



	pci_read_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_STATUS, &status);

	if ((status != 0xffff) && (status & PCI_EXP_DPC_STATUS_TRIGGER))

	if ((!PCI_POSSIBLE_ERROR(status)) && (status & PCI_EXP_DPC_STATUS_TRIGGER))

		return false;



	if (test_bit(PCI_DPC_RECOVERING, &pdev->priv_flags))
@@ -312,7 +312,7 @@ static irqreturn_t dpc_irq(int irq, void *context) 


	pci_read_config_word(pdev, cap + PCI_EXP_DPC_STATUS, &status);



	if (!(status & PCI_EXP_DPC_STATUS_INTERRUPT) || status == (u16)(~0))

	if (!(status & PCI_EXP_DPC_STATUS_INTERRUPT) || PCI_POSSIBLE_ERROR(status))

		return IRQ_NONE;



	pci_write_config_word(pdev, cap + PCI_EXP_DPC_STATUS,