PCI/MSI: Export MSI mode using attributes, not kobjects

The PCI MSI sysfs code is a mess with kobjects for things that don't really
need to be kobjects.  This patch creates attributes dynamically for the MSI
interrupts instead of using kobjects.

Note, this removes a directory from sysfs.  Old MSI kobjects:

  pci_device
     └── msi_irqs
         └── 40
             └── mode

New MSI attributes:

  pci_device
     └── msi_irqs
         └── 40

As there was only one file "mode" with the kobject model, the interrupt
number is now a file that returns the "mode" of the interrupt (msi vs.
msix).

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>

1 files changed, 91 insertions, 75 deletions

diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 3fcd67a16677..f88fa1277802 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -363,6 +363,9 @@ void write_msi_msg(unsigned int irq, struct msi_msg *msg)
 static void free_msi_irqs(struct pci_dev *dev)
 {
         struct msi_desc *entry, *tmp;
+        struct attribute **msi_attrs;
+        struct device_attribute *dev_attr;
+        int count = 0;
 
         list_for_each_entry(entry, &dev->msi_list, list) {
                 int i, nvec;
@@ -398,6 +401,22 @@ static void free_msi_irqs(struct pci_dev *dev)
                 list_del(&entry->list);
                 kfree(entry);
         }
+
+        if (dev->msi_irq_groups) {
+                sysfs_remove_groups(&dev->dev.kobj, dev->msi_irq_groups);
+                msi_attrs = dev->msi_irq_groups[0]->attrs;
+                list_for_each_entry(entry, &dev->msi_list, list) {
+                        dev_attr = container_of(msi_attrs[count],
+                                                struct device_attribute, attr);
+                        kfree(dev_attr->attr.name);
+                        kfree(dev_attr);
+                        ++count;
+                }
+                kfree(msi_attrs);
+                kfree(dev->msi_irq_groups[0]);
+                kfree(dev->msi_irq_groups);
+                dev->msi_irq_groups = NULL;
+        }
 }
 
 static struct msi_desc *alloc_msi_entry(struct pci_dev *dev)
@@ -471,94 +490,95 @@ void pci_restore_msi_state(struct pci_dev *dev)
 }
 EXPORT_SYMBOL_GPL(pci_restore_msi_state);
 
-
-#define to_msi_attr(obj) container_of(obj, struct msi_attribute, attr)
-#define to_msi_desc(obj) container_of(obj, struct msi_desc, kobj)
-
-struct msi_attribute {
-        struct attribute        attr;
-        ssize_t (*show)(struct msi_desc *entry, struct msi_attribute *attr,
-                        char *buf);
-        ssize_t (*store)(struct msi_desc *entry, struct msi_attribute *attr,
-                         const char *buf, size_t count);
-};
-
-static ssize_t show_msi_mode(struct msi_desc *entry, struct msi_attribute *atr,
+static ssize_t msi_mode_show(struct device *dev, struct device_attribute *attr,
                              char *buf)
 {
-        return sprintf(buf, "%s\n", entry->msi_attrib.is_msix ? "msix" : "msi");
-}
-
-static ssize_t msi_irq_attr_show(struct kobject *kobj,
-                                 struct attribute *attr, char *buf)
-{
-        struct msi_attribute *attribute = to_msi_attr(attr);
-        struct msi_desc *entry = to_msi_desc(kobj);
-
-        if (!attribute->show)
-                return -EIO;
-
-        return attribute->show(entry, attribute, buf);
-}
-
-static const struct sysfs_ops msi_irq_sysfs_ops = {
-        .show = msi_irq_attr_show,
-};
-
-static struct msi_attribute mode_attribute =
-        __ATTR(mode, S_IRUGO, show_msi_mode, NULL);
-
-
-static struct attribute *msi_irq_default_attrs[] = {
-        &mode_attribute.attr,
-        NULL
-};
+        struct pci_dev *pdev = to_pci_dev(dev);
+        struct msi_desc *entry;
+        unsigned long irq;
+        int retval;
 
-static void msi_kobj_release(struct kobject *kobj)
-{
-        struct msi_desc *entry = to_msi_desc(kobj);
+        retval = kstrtoul(attr->attr.name, 10, &irq);
+        if (retval)
+                return retval;
 
-        pci_dev_put(entry->dev);
+        list_for_each_entry(entry, &pdev->msi_list, list) {
+                if (entry->irq == irq) {
+                        return sprintf(buf, "%s\n",
+                                       entry->msi_attrib.is_msix ? "msix" : "msi");
+                }
+        }
+        return -ENODEV;
 }
 
-static struct kobj_type msi_irq_ktype = {
-        .release = msi_kobj_release,
-        .sysfs_ops = &msi_irq_sysfs_ops,
-        .default_attrs = msi_irq_default_attrs,
-};
-
 static int populate_msi_sysfs(struct pci_dev *pdev)
 {
+        struct attribute **msi_attrs;
+        struct attribute *msi_attr;
+        struct device_attribute *msi_dev_attr;
+        struct attribute_group *msi_irq_group;
+        const struct attribute_group **msi_irq_groups;
         struct msi_desc *entry;
-        struct kobject *kobj;
-        int ret;
+        int ret = -ENOMEM;
+        int num_msi = 0;
         int count = 0;
 
-        pdev->msi_kset = kset_create_and_add("msi_irqs", NULL, &pdev->dev.kobj);
-        if (!pdev->msi_kset)
-                return -ENOMEM;
+        /* Determine how many msi entries we have */
+        list_for_each_entry(entry, &pdev->msi_list, list) {
+                ++num_msi;
+        }
+        if (!num_msi)
+                return 0;
 
+        /* Dynamically create the MSI attributes for the PCI device */
+        msi_attrs = kzalloc(sizeof(void *) * (num_msi + 1), GFP_KERNEL);
+        if (!msi_attrs)
+                return -ENOMEM;
         list_for_each_entry(entry, &pdev->msi_list, list) {
-                kobj = &entry->kobj;
-                kobj->kset = pdev->msi_kset;
-                pci_dev_get(pdev);
-                ret = kobject_init_and_add(kobj, &msi_irq_ktype, NULL,
-                                     "%u", entry->irq);
-                if (ret)
-                        goto out_unroll;
-
-                count++;
+                char *name = kmalloc(20, GFP_KERNEL);
+                msi_dev_attr = kzalloc(sizeof(*msi_dev_attr), GFP_KERNEL);
+                if (!msi_dev_attr)
+                        goto error_attrs;
+                sprintf(name, "%d", entry->irq);
+                sysfs_attr_init(&msi_dev_attr->attr);
+                msi_dev_attr->attr.name = name;
+                msi_dev_attr->attr.mode = S_IRUGO;
+                msi_dev_attr->show = msi_mode_show;
+                msi_attrs[count] = &msi_dev_attr->attr;
+                ++count;
         }
 
+        msi_irq_group = kzalloc(sizeof(*msi_irq_group), GFP_KERNEL);
+        if (!msi_irq_group)
+                goto error_attrs;
+        msi_irq_group->name = "msi_irqs";
+        msi_irq_group->attrs = msi_attrs;
+
+        msi_irq_groups = kzalloc(sizeof(void *) * 2, GFP_KERNEL);
+        if (!msi_irq_groups)
+                goto error_irq_group;
+        msi_irq_groups[0] = msi_irq_group;
+
+        ret = sysfs_create_groups(&pdev->dev.kobj, msi_irq_groups);
+        if (ret)
+                goto error_irq_groups;
+        pdev->msi_irq_groups = msi_irq_groups;
+
         return 0;
 
-out_unroll:
-        list_for_each_entry(entry, &pdev->msi_list, list) {
-                if (!count)
-                        break;
-                kobject_del(&entry->kobj);
-                kobject_put(&entry->kobj);
-                count--;
+error_irq_groups:
+        kfree(msi_irq_groups);
+error_irq_group:
+        kfree(msi_irq_group);
+error_attrs:
+        count = 0;
+        msi_attr = msi_attrs[count];
+        while (msi_attr) {
+                msi_dev_attr = container_of(msi_attr, struct device_attribute, attr);
+                kfree(msi_attr->name);
+                kfree(msi_dev_attr);
+                ++count;
+                msi_attr = msi_attrs[count];
         }
         return ret;
 }
@@ -925,8 +945,6 @@ void pci_disable_msi(struct pci_dev *dev)
 
         pci_msi_shutdown(dev);
         free_msi_irqs(dev);
-        kset_unregister(dev->msi_kset);
-        dev->msi_kset = NULL;
 }
 EXPORT_SYMBOL(pci_disable_msi);
 
@@ -1023,8 +1041,6 @@ void pci_disable_msix(struct pci_dev *dev)
 
         pci_msix_shutdown(dev);
         free_msi_irqs(dev);
-        kset_unregister(dev->msi_kset);
-        dev->msi_kset = NULL;
 }
 EXPORT_SYMBOL(pci_disable_msix);