linux-kernel - [PATCH v1] PCI: replace msleep to save waiting time

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Message-Id: <20260129071549.425033-1-xiehongyu1@kylinos.cn>
Date: Thu, 29 Jan 2026 15:15:49 +0800
From: Hongyu Xie <xiehongyu1@...inos.cn>
To: bhelgaas@...gle.com
Cc: linux-pci@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Hongyu Xie <xiehongyu1@...inos.cn>
Subject: [PATCH v1] PCI: replace msleep to save waiting time

In pcie_wait_for_link_status, using msleep(1) to wait for link status
change.
But msleep(1) can sleep for nearly 5ms.

ftrace shows:
 0)               |                pcie_wait_for_link_status() {
 0)   0.500 us    |                  pcie_capability_read_word();
 0)   0.580 us    |                  pcie_capability_read_word();
 0) * 10292.26 us |                }

 after changing to usleep_range.
 ftrace shows:

 0)               |                pcie_wait_for_link_status() {
 0)   0.320 us    |                  pcie_capability_read_word();
 0)   0.480 us    |                  pcie_capability_read_word();
 0) # 2483.980 us |                }

 So fix this by using usleep_range.

Signed-off-by: Hongyu Xie <xiehongyu1@...inos.cn>
---
 drivers/pci/pci.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 13dbb405dc31..151364cb767d 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -4484,7 +4484,7 @@ static int pcie_wait_for_link_status(struct pci_dev *pdev,
 		pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnksta);
 		if ((lnksta & lnksta_mask) == lnksta_match)
 			return 0;
-		msleep(1);
+		usleep_range(1000, 1100);
 	} while (time_before(jiffies, end_jiffies));
 
 	return -ETIMEDOUT;
-- 
2.25.1