powerpc/eeh: Introdce flag to protect sysfs

The patch introduces flag EEH_DEV_SYSFS to keep track that the sysfs
entries for the corresponding EEH device (then PCI device) has been
added or removed, in order to avoid race condition.

Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

diff --git a/arch/powerpc/include/asm/eeh.h b/arch/powerpc/include/asm/eeh.h
index 4199d99..d3e5e9b 100644 (file)
--- a/arch/powerpc/include/asm/eeh.h
+++ b/arch/powerpc/include/asm/eeh.h
@@ -90,6 +90,8 @@ struct eeh_pe {
 #define EEH_DEV_IRQ_DISABLED   (1 << 3)        /* Interrupt disabled   */
 #define EEH_DEV_DISCONNECTED   (1 << 4)        /* Removing from PE     */
 
+#define EEH_DEV_SYSFS          (1 << 8)        /* Sysfs created        */
+
 struct eeh_dev {
        int mode;                       /* EEH mode                     */
        int class_code;                 /* Class code of the device     */

diff --git a/arch/powerpc/kernel/eeh.c b/arch/powerpc/kernel/eeh.c
index a5783f1..ea9414c 100644 (file)
--- a/arch/powerpc/kernel/eeh.c
+++ b/arch/powerpc/kernel/eeh.c
@@ -911,6 +911,7 @@ void eeh_add_device_late(struct pci_dev *dev)
                eeh_rmv_from_parent_pe(edev);
                eeh_addr_cache_rmv_dev(edev->pdev);
                eeh_sysfs_remove_device(edev->pdev);
+               edev->mode &= ~EEH_DEV_SYSFS;
 
                edev->pdev = NULL;
                dev->dev.archdata.edev = NULL;
@@ -1016,6 +1017,7 @@ void eeh_remove_device(struct pci_dev *dev)
 
        eeh_addr_cache_rmv_dev(dev);
        eeh_sysfs_remove_device(dev);
+       edev->mode &= ~EEH_DEV_SYSFS;
 }
 
 static int proc_eeh_show(struct seq_file *m, void *v)

diff --git a/arch/powerpc/kernel/eeh_sysfs.c b/arch/powerpc/kernel/eeh_sysfs.c
index 61e2a14..5d753d4 100644 (file)
--- a/arch/powerpc/kernel/eeh_sysfs.c
+++ b/arch/powerpc/kernel/eeh_sysfs.c
@@ -56,26 +56,40 @@ EEH_SHOW_ATTR(eeh_pe_config_addr,  pe_config_addr,  "0x%x");
 
 void eeh_sysfs_add_device(struct pci_dev *pdev)
 {
+       struct eeh_dev *edev = pci_dev_to_eeh_dev(pdev);
        int rc=0;
 
+       if (edev && (edev->mode & EEH_DEV_SYSFS))
+               return;
+
        rc += device_create_file(&pdev->dev, &dev_attr_eeh_mode);
        rc += device_create_file(&pdev->dev, &dev_attr_eeh_config_addr);
        rc += device_create_file(&pdev->dev, &dev_attr_eeh_pe_config_addr);
 
        if (rc)
                printk(KERN_WARNING "EEH: Unable to create sysfs entries\n");
+       else if (edev)
+               edev->mode |= EEH_DEV_SYSFS;
 }
 
 void eeh_sysfs_remove_device(struct pci_dev *pdev)
 {
+       struct eeh_dev *edev = pci_dev_to_eeh_dev(pdev);
+
        /*
         * The parent directory might have been removed. We needn't
         * continue for that case.
         */
-       if (!pdev->dev.kobj.sd)
+       if (!pdev->dev.kobj.sd) {
+               if (edev)
+                       edev->mode &= ~EEH_DEV_SYSFS;
                return;
+       }
 
        device_remove_file(&pdev->dev, &dev_attr_eeh_mode);
        device_remove_file(&pdev->dev, &dev_attr_eeh_config_addr);
        device_remove_file(&pdev->dev, &dev_attr_eeh_pe_config_addr);
+
+       if (edev)
+               edev->mode &= ~EEH_DEV_SYSFS;
 }

diff --git a/arch/powerpc/platforms/powernv/eeh-powernv.c b/arch/powerpc/platforms/powernv/eeh-powernv.c
index 4361a5c..79663d2 100644 (file)
--- a/arch/powerpc/platforms/powernv/eeh-powernv.c
+++ b/arch/powerpc/platforms/powernv/eeh-powernv.c
@@ -122,8 +122,8 @@ static int powernv_eeh_dev_probe(struct pci_dev *dev, void *flag)
                return 0;
 
        /* Initialize eeh device */
-       edev->class_code        = dev->class;
-       edev->mode              = 0;
+       edev->class_code = dev->class;
+       edev->mode      &= 0xFFFFFF00;
        if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE)
                edev->mode |= EEH_DEV_BRIDGE;
        if (pci_is_pcie(dev)) {

diff --git a/arch/powerpc/platforms/pseries/eeh_pseries.c b/arch/powerpc/platforms/pseries/eeh_pseries.c
index 9e80f0a..7fbc25b 100644 (file)
--- a/arch/powerpc/platforms/pseries/eeh_pseries.c
+++ b/arch/powerpc/platforms/pseries/eeh_pseries.c
@@ -218,7 +218,7 @@ static void *pseries_eeh_of_probe(struct device_node *dn, void *flag)
         */
        edev->class_code = *class_code;
        edev->pcie_cap = pseries_eeh_find_cap(dn, PCI_CAP_ID_EXP);
-       edev->mode = 0;
+       edev->mode &= 0xFFFFFF00;
        if ((edev->class_code >> 8) == PCI_CLASS_BRIDGE_PCI) {
                edev->mode |= EEH_DEV_BRIDGE;
                if (edev->pcie_cap) {