From: Koichiro Den <den@valinux.co.jp>
To: "Jon Mason" <jdmason@kudzu.us>,
"Dave Jiang" <dave.jiang@intel.com>,
"Allen Hubbe" <allenbh@gmail.com>,
"Manivannan Sadhasivam" <mani@kernel.org>,
"Krzysztof Wilczyński" <kwilczynski@kernel.org>,
"Kishon Vijay Abraham I" <kishon@kernel.org>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"Frank Li" <Frank.Li@nxp.com>,
"Jerome Brunet" <jbrunet@baylibre.com>,
"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
"Niklas Cassel" <cassel@kernel.org>
Cc: linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org,
ntb@lists.linux.dev
Subject: [PATCH v4 04/12] PCI: endpoint: pci-epf-vntb: Reject unusable doorbell counts
Date: Wed, 13 May 2026 11:49:15 +0900 [thread overview]
Message-ID: <20260513024923.451765-5-den@valinux.co.jp> (raw)
In-Reply-To: <20260513024923.451765-1-den@valinux.co.jp>
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 <den@valinux.co.jp>
---
Changes since v3:
- New patch.
drivers/pci/endpoint/functions/pci-epf-vntb.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
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;
}
--
2.51.0
next prev parent reply other threads:[~2026-05-13 2:49 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-13 2:49 [PATCH v4 00/12] PCI: endpoint: pci-epf-vntb / NTB: epf: Enable per-doorbell bit handling Koichiro Den
2026-05-13 2:49 ` [PATCH v4 01/12] PCI: endpoint: pci-epf-vntb: Document legacy MSI doorbell offset Koichiro Den
2026-05-13 2:49 ` [PATCH v4 02/12] PCI: endpoint: pci-epf-vntb: Defer pci_epc_raise_irq() out of atomic context Koichiro Den
2026-05-14 18:53 ` Frank Li
2026-05-13 2:49 ` [PATCH v4 03/12] PCI: endpoint: pci-epf-vntb: Report 0-based doorbell vector via ntb_db_event() Koichiro Den
2026-05-13 2:49 ` Koichiro Den [this message]
2026-05-14 18:55 ` [PATCH v4 04/12] PCI: endpoint: pci-epf-vntb: Reject unusable doorbell counts Frank Li
2026-05-13 2:49 ` [PATCH v4 05/12] PCI: endpoint: pci-epf-vntb: Guard configfs writes after EPC attach Koichiro Den
2026-05-14 18:57 ` Frank Li
2026-05-13 2:49 ` [PATCH v4 06/12] PCI: endpoint: pci-epf-vntb: Exclude reserved slots from db_valid_mask Koichiro Den
2026-05-13 2:49 ` [PATCH v4 07/12] PCI: endpoint: pci-epf-vntb: Implement db_vector_count/mask for doorbells Koichiro Den
2026-05-14 19:02 ` Frank Li
2026-05-13 2:49 ` [PATCH v4 08/12] NTB: epf: Document legacy doorbell slot offset in ntb_epf_peer_db_set() Koichiro Den
2026-05-13 2:49 ` [PATCH v4 09/12] NTB: epf: Make db_valid_mask cover only real doorbell bits Koichiro Den
2026-05-26 22:21 ` Dave Jiang
2026-05-13 2:49 ` [PATCH v4 10/12] NTB: epf: Report 0-based doorbell vector via ntb_db_event() Koichiro Den
2026-05-14 19:03 ` Frank Li
2026-05-26 22:28 ` Dave Jiang
2026-05-13 2:49 ` [PATCH v4 11/12] NTB: epf: Fix doorbell bitmask and IRQ vector handling Koichiro Den
2026-05-14 19:06 ` Frank Li
2026-05-26 22:36 ` Dave Jiang
2026-05-13 2:49 ` [PATCH v4 12/12] NTB: epf: Implement db_vector_count/mask for doorbells Koichiro Den
2026-05-26 22:47 ` Dave Jiang
2026-06-23 16:31 ` Bjorn Helgaas
2026-06-24 1:35 ` Koichiro Den
2026-05-19 14:42 ` [PATCH v4 00/12] PCI: endpoint: pci-epf-vntb / NTB: epf: Enable per-doorbell bit handling Manivannan Sadhasivam
2026-05-19 21:29 ` Dave Jiang
2026-05-21 6:29 ` Koichiro Den
2026-05-26 14:45 ` Dave Jiang
2026-05-26 15:56 ` Koichiro Den
2026-05-26 16:27 ` Dave Jiang
2026-05-27 9:09 ` Manivannan Sadhasivam
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