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>

diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci
index 5210a51..a3c5a66 100644 (file)
--- a/Documentation/ABI/testing/sysfs-bus-pci
+++ b/Documentation/ABI/testing/sysfs-bus-pci
@@ -70,18 +70,15 @@ Date:               September, 2011
 Contact:       Neil Horman <nhorman@tuxdriver.com>
 Description:
                The /sys/devices/.../msi_irqs directory contains a variable set
-               of sub-directories, with each sub-directory being named after a
-               corresponding msi irq vector allocated to that device.  Each
-               numbered sub-directory N contains attributes of that irq.
-               Note that this directory is not created for device drivers which
-               do not support msi irqs
+               of files, with each file being named after a corresponding msi
+               irq vector allocated to that device.
 
-What:          /sys/bus/pci/devices/.../msi_irqs/<N>/mode
+What:          /sys/bus/pci/devices/.../msi_irqs/<N>
 Date:          September 2011
 Contact:       Neil Horman <nhorman@tuxdriver.com>
 Description:
                This attribute indicates the mode that the irq vector named by
-               the parent directory is in (msi vs. msix)
+               the file is in (msi vs. msix)
 
 What:          /sys/bus/pci/devices/.../remove
 Date:          January 2009

diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 3fcd67a..f88fa12 100644 (file)
--- 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);
 

diff --git a/include/linux/pci.h b/include/linux/pci.h
index 1084a15..36a5b18 100644 (file)
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -351,7 +351,7 @@ struct pci_dev {
        struct bin_attribute *res_attr_wc[DEVICE_COUNT_RESOURCE]; /* sysfs file for WC mapping of resources */
 #ifdef CONFIG_PCI_MSI
        struct list_head msi_list;
-       struct kset *msi_kset;
+       const struct attribute_group **msi_irq_groups;
 #endif
        struct pci_vpd *vpd;
 #ifdef CONFIG_PCI_ATS