[PATCH] pci: irq: Add an early parameter to limit pci irq numbers

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]


Some platforms (such as LoongArch) cannot provide enough irq numbers as
many as logical cpu numbers. So we should limit pci irq numbers when
allocate msi/msix vectors, otherwise some device drivers may fail at
initialization. This patch add a cmdline parameter "pci_irq_limit=xxxx"
to control the limit.

The default pci msi/msix number limit is defined 32 for LoongArch and
NR_IRQS for other platforms.

Signed-off-by: Juxin Gao <gaojuxin@xxxxxxxxxxx>
Signed-off-by: Huacai Chen <chenhuacai@xxxxxxxxxxx>
 drivers/pci/msi/msi.c | 26 +++++++++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/msi/msi.c b/drivers/pci/msi/msi.c
index ef1d8857a51b..6617381e50e7 100644
--- a/drivers/pci/msi/msi.c
+++ b/drivers/pci/msi/msi.c
@@ -402,12 +402,34 @@ static int msi_capability_init(struct pci_dev *dev, int nvec,
 	return ret;
+static int pci_irq_limits = DEFAULT_PCI_IRQ_LIMITS;
+static int __init pci_irq_limit(char *str)
+	get_option(&str, &pci_irq_limits);
+	if (pci_irq_limits == 0)
+		pci_irq_limits = DEFAULT_PCI_IRQ_LIMITS;
+	return 0;
+early_param("pci_irq_limit", pci_irq_limit);
 int __pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec,
 			   struct irq_affinity *affd)
 	int nvec;
 	int rc;
+	maxvec = clamp_val(maxvec, 0, pci_irq_limits);
 	if (!pci_msi_supported(dev, minvec) || dev->current_state != PCI_D0)
 		return -EINVAL;
@@ -776,7 +798,9 @@ static bool pci_msix_validate_entries(struct pci_dev *dev, struct msix_entry *en
 int __pci_enable_msix_range(struct pci_dev *dev, struct msix_entry *entries, int minvec,
 			    int maxvec, struct irq_affinity *affd, int flags)
-	int hwsize, rc, nvec = maxvec;
+	int hwsize, rc, nvec;
+	nvec = clamp_val(maxvec, 0, pci_irq_limits);
 	if (maxvec < minvec)
 		return -ERANGE;

[Index of Archives]     [DMA Engine]     [Linux Coverity]     [Linux USB]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]     [Greybus]

  Powered by Linux