Patch "PCI: Rework pcie_retrain_link() wait loop" has been added to the 4.19-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    PCI: Rework pcie_retrain_link() wait loop

to the 4.19-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     pci-rework-pcie_retrain_link-wait-loop.patch
and it can be found in the queue-4.19 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 5f19ed01df565cd694687ba28e07661f34956445
Author: Stefan Mätje <stefan.maetje@xxxxxx>
Date:   Fri Mar 29 18:07:36 2019 +0100

    PCI: Rework pcie_retrain_link() wait loop
    
    [ Upstream commit 658eec837b11fbfab9082ebf8da24d94cefa47c0 ]
    
    Transform wait code to a "do {} while (time_before())" loop as recommended
    by reviewer.  No functional change intended.
    
    Signed-off-by: Stefan Mätje <stefan.maetje@xxxxxx>
    Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
    Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
    Stable-dep-of: e7e39756363a ("PCI/ASPM: Avoid link retraining race")
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 279f9f0197b01..598e246fa70ed 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -206,7 +206,7 @@ static void pcie_clkpm_cap_init(struct pcie_link_state *link, int blacklist)
 static bool pcie_retrain_link(struct pcie_link_state *link)
 {
 	struct pci_dev *parent = link->pdev;
-	unsigned long start_jiffies;
+	unsigned long end_jiffies;
 	u16 reg16;
 
 	pcie_capability_read_word(parent, PCI_EXP_LNKCTL, &reg16);
@@ -223,15 +223,13 @@ static bool pcie_retrain_link(struct pcie_link_state *link)
 	}
 
 	/* Wait for link training end. Break out after waiting for timeout */
-	start_jiffies = jiffies;
-	for (;;) {
+	end_jiffies = jiffies + LINK_RETRAIN_TIMEOUT;
+	do {
 		pcie_capability_read_word(parent, PCI_EXP_LNKSTA, &reg16);
 		if (!(reg16 & PCI_EXP_LNKSTA_LT))
 			break;
-		if (time_after(jiffies, start_jiffies + LINK_RETRAIN_TIMEOUT))
-			break;
 		msleep(1);
-	}
+	} while (time_before(jiffies, end_jiffies));
 	return !(reg16 & PCI_EXP_LNKSTA_LT);
 }