This is a note to let you know that I've just added the patch titled
PCI: pciehp: Use RMW accessors for changing LNKCTL
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-pciehp-use-rmw-accessors-for-changing-lnkctl.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 4d307827ffd34a1c2fdfc319dce514710ff484d8
Author: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
Date: Mon Jul 17 15:04:55 2023 +0300
PCI: pciehp: Use RMW accessors for changing LNKCTL
[ Upstream commit 5f75f96c61039151c193775d776fde42477eace1 ]
As hotplug is not the only driver touching LNKCTL, use the RMW capability
accessor which handles concurrent changes correctly.
Suggested-by: Lukas Wunner <lukas@xxxxxxxxx>
Fixes: 7f822999e12a ("PCI: pciehp: Add Disable/enable link functions")
Link: https://lore.kernel.org/r/20230717120503.15276-4-ilpo.jarvinen@xxxxxxxxxxxxxxx
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Acked-by: "Rafael J. Wysocki" <rafael@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index 7392b26e9f158..04630106269af 100644
--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -298,17 +298,11 @@ int pciehp_check_link_status(struct controller *ctrl)
static int __pciehp_link_set(struct controller *ctrl, bool enable)
{
struct pci_dev *pdev = ctrl_dev(ctrl);
- u16 lnk_ctrl;
- pcie_capability_read_word(pdev, PCI_EXP_LNKCTL, &lnk_ctrl);
+ pcie_capability_clear_and_set_word(pdev, PCI_EXP_LNKCTL,
+ PCI_EXP_LNKCTL_LD,
+ enable ? 0 : PCI_EXP_LNKCTL_LD);
- if (enable)
- lnk_ctrl &= ~PCI_EXP_LNKCTL_LD;
- else
- lnk_ctrl |= PCI_EXP_LNKCTL_LD;
-
- pcie_capability_write_word(pdev, PCI_EXP_LNKCTL, lnk_ctrl);
- ctrl_dbg(ctrl, "%s: lnk_ctrl = %x\n", __func__, lnk_ctrl);
return 0;
}
