linux-kernel - [RFC PATCH 13/25] NTB/msi: Skip mw_set

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Message-ID: <20251023071916.901355-14-den@valinux.co.jp>
Date: Thu, 23 Oct 2025 16:19:04 +0900
From: Koichiro Den <den@...inux.co.jp>
To: ntb@...ts.linux.dev,
	linux-pci@...r.kernel.org,
	dmaengine@...r.kernel.org,
	linux-kernel@...r.kernel.org
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Subject: [RFC PATCH 13/25] NTB/msi: Skip mw_set_trans() if already configured

Return early if msi->base_addr is already set, avoiding redundant
mw_set_trans() calls and unnecessary reprogramming of address
translations.

Signed-off-by: Koichiro Den <den@...inux.co.jp>
---
 drivers/ntb/msi.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/ntb/msi.c b/drivers/ntb/msi.c
index 00218cfa6fd5..6d48418aa756 100644
--- a/drivers/ntb/msi.c
+++ b/drivers/ntb/msi.c
@@ -106,6 +106,9 @@ int ntb_msi_setup_mws(struct ntb_dev *ntb)
 	if (!ntb->msi)
 		return -EINVAL;
 
+	if (ntb->msi->base_addr)
+		return 0;
+
 	scoped_guard (msi_descs_lock, &ntb->pdev->dev) {
 		desc = msi_first_desc(&ntb->pdev->dev, MSI_DESC_ASSOCIATED);
 		addr = desc->msg.address_lo + ((uint64_t)desc->msg.address_hi << 32);
-- 
2.48.1