From: Koichiro Den Date: Wed, 13 May 2026 02:49:15 +0000 (+0900) Subject: PCI: endpoint: pci-epf-vntb: Reject unusable doorbell counts X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f417c400a6683c62cdead42013f60872fda84013;p=thirdparty%2Flinux.git PCI: endpoint: pci-epf-vntb: Reject unusable doorbell counts pci-epf-vntb reserves slot 0 for link events and keeps slot 1 unused for legacy layout compatibility. A db_count smaller than MIN_DB_COUNT leaves no usable doorbell slot after those reservations. Reject such configurations when configuring interrupts. While at it, move MAX_DB_COUNT next to MIN_DB_COUNT. They are used as a pair in the range check, and keeping them together makes the valid doorbell range easier to read. Signed-off-by: Koichiro Den Signed-off-by: Manivannan Sadhasivam Signed-off-by: Bjorn Helgaas Reviewed-by: Frank Li Link: https://patch.msgid.link/20260513024923.451765-5-den@valinux.co.jp --- diff --git a/drivers/pci/endpoint/functions/pci-epf-vntb.c b/drivers/pci/endpoint/functions/pci-epf-vntb.c index d31e2eee0869..818ae5999976 100644 --- a/drivers/pci/endpoint/functions/pci-epf-vntb.c +++ b/drivers/pci/endpoint/functions/pci-epf-vntb.c @@ -67,7 +67,6 @@ static struct workqueue_struct *kpcintb_workqueue; #define NTB_MW_OFFSET 2 #define DB_COUNT_MASK GENMASK(15, 0) #define MSIX_ENABLE BIT(16) -#define MAX_DB_COUNT 32 #define MAX_MW 4 /* Limit per-work execution to avoid monopolizing kworker on doorbell storms. */ @@ -89,6 +88,9 @@ enum epf_irq_slot { EPF_IRQ_DB_START, }; +#define MIN_DB_COUNT (EPF_IRQ_DB_START + 1) +#define MAX_DB_COUNT 32 + /* * +--------------------------------------------------+ Base * | | @@ -512,9 +514,9 @@ static int epf_ntb_configure_interrupt(struct epf_ntb *ntb) return -EINVAL; } - if (!ntb->db_count || ntb->db_count > MAX_DB_COUNT) { - dev_err(dev, "DB count %d out of range (1 - %d)\n", - ntb->db_count, MAX_DB_COUNT); + if (ntb->db_count < MIN_DB_COUNT || ntb->db_count > MAX_DB_COUNT) { + dev_err(dev, "DB count %d out of range (%d - %d)\n", + ntb->db_count, MIN_DB_COUNT, MAX_DB_COUNT); return -EINVAL; }