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 v3 09/10] NTB: epf: Fix doorbell bitmask handling in db_read/db_clear
Date: Mon, 23 Mar 2026 12:15:43 +0900 [thread overview]
Message-ID: <20260323031544.2598111-10-den@valinux.co.jp> (raw)
In-Reply-To: <20260323031544.2598111-1-den@valinux.co.jp>
The EPF driver currently stores the incoming doorbell as a vector number
(irq_no + 1) in db_val and db_clear() clears all bits unconditionally.
This breaks db_read()/db_clear() semantics when multiple doorbells are
used.
Store doorbells as a bitmask (BIT_ULL(vector)) and make
db_clear(db_bits) clear only the specified bits. Use atomic64 operations
as db_val is updated from interrupt context.
Fixes: 812ce2f8d14e ("NTB: Add support for EPF PCI Non-Transparent Bridge")
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Suggested-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Koichiro Den <den@valinux.co.jp>
---
drivers/ntb/hw/epf/ntb_hw_epf.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/drivers/ntb/hw/epf/ntb_hw_epf.c b/drivers/ntb/hw/epf/ntb_hw_epf.c
index 67cdc5d729d5..741d30821390 100644
--- a/drivers/ntb/hw/epf/ntb_hw_epf.c
+++ b/drivers/ntb/hw/epf/ntb_hw_epf.c
@@ -6,6 +6,7 @@
* Author: Kishon Vijay Abraham I <kishon@ti.com>
*/
+#include <linux/atomic.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/pci.h>
@@ -108,7 +109,7 @@ struct ntb_epf_dev {
unsigned int self_spad;
unsigned int peer_spad;
- int db_val;
+ atomic64_t db_val;
u64 db_valid_mask;
};
@@ -337,15 +338,16 @@ static irqreturn_t ntb_epf_vec_isr(int irq, void *dev)
int irq_no;
irq_no = irq - pci_irq_vector(ndev->ntb.pdev, 0);
- ndev->db_val = irq_no + 1;
if (irq_no == EPF_IRQ_LINK) {
ntb_link_event(&ndev->ntb);
} else if (irq_no == EPF_IRQ_RESERVED_DB) {
dev_warn_ratelimited(ndev->dev,
"Unexpected irq_no 1 received. Treat it as DB#0.\n");
+ atomic64_or(BIT_ULL(0), &ndev->db_val);
ntb_db_event(&ndev->ntb, 0);
} else {
+ atomic64_or(BIT_ULL(irq_no - EPF_IRQ_DB_START), &ndev->db_val);
ntb_db_event(&ndev->ntb, irq_no - EPF_IRQ_DB_START);
}
@@ -530,7 +532,7 @@ static u64 ntb_epf_db_read(struct ntb_dev *ntb)
{
struct ntb_epf_dev *ndev = ntb_ndev(ntb);
- return ndev->db_val;
+ return atomic64_read(&ndev->db_val);
}
static int ntb_epf_db_clear_mask(struct ntb_dev *ntb, u64 db_bits)
@@ -542,7 +544,7 @@ static int ntb_epf_db_clear(struct ntb_dev *ntb, u64 db_bits)
{
struct ntb_epf_dev *ndev = ntb_ndev(ntb);
- ndev->db_val = 0;
+ atomic64_and(~db_bits, &ndev->db_val);
return 0;
}
--
2.51.0
next prev parent reply other threads:[~2026-03-23 3:16 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-23 3:15 [PATCH v3 00/10] PCI: endpoint: pci-epf-vntb / NTB: epf: Enable per-doorbell bit handling Koichiro Den
2026-03-23 3:15 ` [PATCH v3 01/10] PCI: endpoint: pci-epf-vntb: Document legacy MSI doorbell offset Koichiro Den
2026-03-23 3:15 ` [PATCH v3 02/10] PCI: endpoint: pci-epf-vntb: Defer pci_epc_raise_irq() out of atomic context Koichiro Den
2026-03-23 18:27 ` Frank Li
2026-05-01 16:26 ` Manivannan Sadhasivam
2026-05-11 7:54 ` Koichiro Den
2026-03-23 3:15 ` [PATCH v3 03/10] PCI: endpoint: pci-epf-vntb: Report 0-based doorbell vector via ntb_db_event() Koichiro Den
2026-03-23 3:15 ` [PATCH v3 04/10] PCI: endpoint: pci-epf-vntb: Exclude reserved slots from db_valid_mask Koichiro Den
2026-03-23 3:15 ` [PATCH v3 05/10] PCI: endpoint: pci-epf-vntb: Implement db_vector_count/mask for doorbells Koichiro Den
2026-03-23 3:15 ` [PATCH v3 06/10] NTB: epf: Document legacy doorbell slot offset in ntb_epf_peer_db_set() Koichiro Den
2026-03-23 3:15 ` [PATCH v3 07/10] NTB: epf: Make db_valid_mask cover only real doorbell bits Koichiro Den
2026-03-23 3:15 ` [PATCH v3 08/10] NTB: epf: Report 0-based doorbell vector via ntb_db_event() Koichiro Den
2026-03-23 3:15 ` Koichiro Den [this message]
2026-05-01 16:29 ` [PATCH v3 09/10] NTB: epf: Fix doorbell bitmask handling in db_read/db_clear Manivannan Sadhasivam
2026-05-11 9:15 ` Koichiro Den
2026-03-23 3:15 ` [PATCH v3 10/10] NTB: epf: Implement db_vector_count/mask for doorbells Koichiro Den
2026-03-23 15:43 ` [PATCH v3 00/10] PCI: endpoint: pci-epf-vntb / NTB: epf: Enable per-doorbell bit handling Koichiro Den
2026-03-25 6:23 ` Niklas Cassel
2026-03-25 8:44 ` Koichiro Den
2026-04-07 15:21 ` Koichiro Den
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