[tip: irq/msi] genirq/msi: Add mutex for MSI list protection

tip-bot2 for Thomas Gleixner
2021-12-16T21:42:28Z

The following commit has been merged into the irq/msi branch of tip:

Commit-ID: b5f687f97d1e112493fe0447a1fb09fbd93c334b
Gitweb: https://git.kernel.org/tip/b5f687f97d1e112493fe0447a1fb09fbd93c334b
Author: Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Mon, 06 Dec 2021 23:51:05 +01:00
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Thu, 16 Dec 2021 22:22:17 +01:00

genirq/msi: Add mutex for MSI list protection

For upcoming runtime extensions of MSI-X interrupts it's required to
protect the MSI descriptor list. Add a mutex to struct msi_device_data and
provide lock/unlock functions.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Nishanth Menon <nm@ti.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20211206210747.708877269@linutronix.de

---
include/linux/msi.h | 5 +++++
kernel/irq/msi.c | 21 +++++++++++++++++++++
2 files changed, 26 insertions(+)

diff --git a/include/linux/msi.h b/include/linux/msi.h
index 4223e47..2cf6c53 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -3,6 +3,7 @@
#define LINUX_MSI_H

#include <linux/cpumask.h>
+#include <linux/mutex.h>
#include <linux/list.h>
#include <asm/msi.h>

@@ -145,17 +146,21 @@ struct msi_desc {
* @attrs: Pointer to the sysfs attribute group
* @platform_data: Platform-MSI specific data
* @list: List of MSI descriptors associated to the device
+ * @mutex: Mutex protecting the MSI list
*/
struct msi_device_data {
unsigned long properties;
const struct attribute_group **attrs;
struct platform_msi_priv_data *platform_data;
struct list_head list;
+ struct mutex mutex;
};

int msi_setup_device_data(struct device *dev);

unsigned int msi_get_virq(struct device *dev, unsigned int index);
+void msi_lock_descs(struct device *dev);
+void msi_unlock_descs(struct device *dev);

/* Helpers to hide struct msi_desc implementation details */
#define msi_desc_to_dev(desc) ((desc)->dev)
diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c
index c66787d..97ec245 100644
--- a/kernel/irq/msi.c
+++ b/kernel/irq/msi.c
@@ -103,12 +103,33 @@ int msi_setup_device_data(struct device *dev)
return -ENOMEM;

INIT_LIST_HEAD(&md->list);
+ mutex_init(&md->mutex);
dev->msi.data = md;
devres_add(dev, md);
return 0;
}

/**
+ * msi_lock_descs - Lock the MSI descriptor storage of a device
+ * @dev: Device to operate on
+ */
+void msi_lock_descs(struct device *dev)
+{
+ mutex_lock(&dev->msi.data->mutex);
+}
+EXPORT_SYMBOL_GPL(msi_lock_descs);
+
+/**
+ * msi_unlock_descs - Unlock the MSI descriptor storage of a device
+ * @dev: Device to operate on
+ */
+void msi_unlock_descs(struct device *dev)
+{
+ mutex_unlock(&dev->msi.data->mutex);
+}
+EXPORT_SYMBOL_GPL(msi_unlock_descs);
+
+/**
* msi_get_virq - Return Linux interrupt number of a MSI interrupt
* @dev: Device to operate on
* @index: MSI interrupt index to look for (0-based)