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SubjectRe: [PATCH] PCI: export MSI mode using attributes, not kobjects
On Wed, Nov 27, 2013 at 10:46:52AM -0800, Greg Kroah-Hartman wrote:
>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>

Works like a charm for me.

FWIW,

Reviewed-by: Veaceslav Falico <vfalico@redhat.com>

>
>---
>
>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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