6.11-stable review patch. If anyone has any objections, please let me know.
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From: Niklas Schnelle schnelle@linux.ibm.com
[ Upstream commit c4a585e952ca403a370586d3f16e8331a7564901 ]
In commit 6ee600bfbe0f ("s390/pci: remove hotplug slot when releasing the device") the zpci_exit_slot() was moved from zpci_device_reserved() to zpci_release_device() with the intention of keeping the hotplug slot around until the device is actually removed.
Now zpci_release_device() is only called once all references are dropped. Since the zPCI subsystem only drops its reference once the device is in the reserved state it follows that zpci_release_device() must only deal with devices in the reserved state. Despite that it contains code to tear down from both configured and standby state. For the standby case this already includes the removal of the hotplug slot so would cause a double removal if a device was ever removed in either configured or standby state.
Instead of causing a potential double removal in a case that should never happen explicitly WARN_ON() if a device in non-reserved state is released and get rid of the dead code cases.
Fixes: 6ee600bfbe0f ("s390/pci: remove hotplug slot when releasing the device") Reviewed-by: Matthew Rosato mjrosato@linux.ibm.com Reviewed-by: Gerd Bayer gbayer@linux.ibm.com Tested-by: Gerd Bayer gbayer@linux.ibm.com Signed-off-by: Niklas Schnelle schnelle@linux.ibm.com Signed-off-by: Heiko Carstens hca@linux.ibm.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/s390/pci/pci.c | 34 +++++++++------------------------- 1 file changed, 9 insertions(+), 25 deletions(-)
diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c index 759983d0e63ed..827b4c7b4688c 100644 --- a/arch/s390/pci/pci.c +++ b/arch/s390/pci/pci.c @@ -918,10 +918,8 @@ void zpci_device_reserved(struct zpci_dev *zdev) void zpci_release_device(struct kref *kref) { struct zpci_dev *zdev = container_of(kref, struct zpci_dev, kref); - int ret;
- if (zdev->has_hp_slot) - zpci_exit_slot(zdev); + WARN_ON(zdev->state != ZPCI_FN_STATE_RESERVED);
if (zdev->zbus->bus) zpci_bus_remove_device(zdev, false); @@ -929,28 +927,14 @@ void zpci_release_device(struct kref *kref) if (zdev_enabled(zdev)) zpci_disable_device(zdev);
- switch (zdev->state) { - case ZPCI_FN_STATE_CONFIGURED: - ret = sclp_pci_deconfigure(zdev->fid); - zpci_dbg(3, "deconf fid:%x, rc:%d\n", zdev->fid, ret); - fallthrough; - case ZPCI_FN_STATE_STANDBY: - if (zdev->has_hp_slot) - zpci_exit_slot(zdev); - spin_lock(&zpci_list_lock); - list_del(&zdev->entry); - spin_unlock(&zpci_list_lock); - zpci_dbg(3, "rsv fid:%x\n", zdev->fid); - fallthrough; - case ZPCI_FN_STATE_RESERVED: - if (zdev->has_resources) - zpci_cleanup_bus_resources(zdev); - zpci_bus_device_unregister(zdev); - zpci_destroy_iommu(zdev); - fallthrough; - default: - break; - } + if (zdev->has_hp_slot) + zpci_exit_slot(zdev); + + if (zdev->has_resources) + zpci_cleanup_bus_resources(zdev); + + zpci_bus_device_unregister(zdev); + zpci_destroy_iommu(zdev); zpci_dbg(3, "rem fid:%x\n", zdev->fid); kfree_rcu(zdev, rcu); }