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Subject[PATCH] PCI: export MSI mode using attributes, not kobjects
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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 the current MSI interrupt sysfs
code:

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>

---

Neil, can you test this patch to see if irqbalance works as-is or not?

thanks,

greg k-h

drivers/pci/msi.c | 152 +++++++++++++++++++++++++---------------------------
include/linux/pci.h | 2
2 files changed, 76 insertions(+), 78 deletions(-)

--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -363,6 +363,9 @@ void write_msi_msg(unsigned int irq, str
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
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)
@@ -471,96 +490,79 @@ void pci_restore_msi_state(struct pci_de
}
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);
-
+ struct pci_dev *pdev = to_pci_dev(dev);
+ struct msi_desc *entry;
+ unsigned long irq;
+ int retval;

-static struct attribute *msi_irq_default_attrs[] = {
- &mode_attribute.attr,
- NULL
-};
+ retval = kstrtoul(attr->attr.name, 10, &irq);
+ if (retval)
+ return retval;

-static void msi_kobj_release(struct kobject *kobj)
-{
- struct msi_desc *entry = to_msi_desc(kobj);
-
- 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 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 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) {
- 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++;
+ ++num_msi;
}
+ if (!num_msi)
+ return 0;

- return 0;
-
-out_unroll:
+ /* 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) {
- if (!count)
- break;
- kobject_del(&entry->kobj);
- kobject_put(&entry->kobj);
- count--;
+ char *name = kmalloc(20, GFP_KERNEL);
+ msi_dev_attr = kzalloc(sizeof(*msi_dev_attr), GFP_KERNEL);
+ if (!msi_dev_attr)
+ return -ENOMEM;
+ sprintf(name, "%d", entry->irq);
+ 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;
}
- return ret;
+
+ msi_irq_group = kzalloc(sizeof(*msi_irq_group), GFP_KERNEL);
+ if (!msi_irq_group)
+ return -ENOMEM;
+ 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)
+ return -ENOMEM;
+ msi_irq_groups[0] = msi_irq_group;
+
+ ret = sysfs_create_groups(&pdev->dev.kobj, msi_irq_groups);
+ if (ret)
+ return ret;
+ pdev->msi_irq_groups = msi_irq_groups;
+
+ return 0;
}

/**
@@ -925,8 +927,6 @@ 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 +1023,6 @@ void pci_disable_msix(struct pci_dev *de

pci_msix_shutdown(dev);
free_msi_irqs(dev);
- kset_unregister(dev->msi_kset);
- dev->msi_kset = NULL;
}
EXPORT_SYMBOL(pci_disable_msix);

--- 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
--
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