When a device is hotplugged out, the PCI resource is released in the
kernel, the UIO file descriptor will disappear and the irq will be
released. After this, a kernel crash will be caused if the igb uio driver
tries to access or release these resources.
And more, uio_remove will be called unexpectedly before uio_release
when device be hotpluggged out, the uio_remove procedure will
free resources that are required by uio_release. This will later affect the
usage of interrupt as there is no way to disable the interrupt which is
defined in uio_release.
To prevent this, the hotplug removal needs to be identified and processed
accordingly in igb uio driver.
This patch proposes the addition of enum rte_udev_state in the
rte_uio_pci_dev struct. This will store the state of the uio device as one
of the following: probed/opened/released/removed.
This patch also checks the kobject's remove_uevent_sent state to detect if
the removal status is hotplug-out. Once a hotplug-out is detected, it will
call uio_release and set the uio status to "removed". After that, uio will
check the status in the uio_release function. If uio has already been
removed, it will only free the dirty uio resource.
Signed-off-by: Jeff Guo <jia....@intel.com>
Acked-by: Shaopeng He <shaopeng...@intel.com>
---
v10->v9:
refine commmit log.
---
kernel/linux/igb_uio/igb_uio.c | 69 +++++++++++++++++++++++++++++++++---------
1 file changed, 55 insertions(+), 14 deletions(-)
diff --git a/kernel/linux/igb_uio/igb_uio.c b/kernel/linux/igb_uio/igb_uio.c
index 3398eac..d126371 100644
--- a/kernel/linux/igb_uio/igb_uio.c
+++ b/kernel/linux/igb_uio/igb_uio.c
@@ -19,6 +19,14 @@
#include "compat.h"
+/* uio pci device state */
+enum rte_udev_state {
+ RTE_UDEV_PROBED,
+ RTE_UDEV_OPENNED,
+ RTE_UDEV_RELEASED,
+ RTE_UDEV_REMOVED,
+};
+
/**
* A structure describing the private information for a uio device.
*/
@@ -28,6 +36,7 @@ struct rte_uio_pci_dev {
enum rte_intr_mode mode;
struct mutex lock;
int refcnt;
+ enum rte_udev_state state;
};
static int wc_activate;
@@ -309,6 +318,17 @@ igbuio_pci_disable_interrupts(struct rte_uio_pci_dev *udev)
#endif
}
+/* Unmap previously ioremap'd resources */
+static void
+igbuio_pci_release_iomem(struct uio_info *info)
+{
+ int i;
+
+ for (i = 0; i < MAX_UIO_MAPS; i++) {
+ if (info->mem[i].internal_addr)
+ iounmap(info->mem[i].internal_addr);
+ }
+}
/**
* This gets called while opening uio device file.
@@ -331,20 +351,35 @@ igbuio_pci_open(struct uio_info *info, struct inode
*inode)
/* enable interrupts */
err = igbuio_pci_enable_interrupts(udev);
- mutex_unlock(&udev->lock);
if (err) {
dev_err(&dev->dev, "Enable interrupt fails\n");
+ pci_clear_master(dev);
+ mutex_unlock(&udev->lock);
return err;
}
+ udev->state = RTE_UDEV_OPENNED;
+ mutex_unlock(&udev->lock);
return 0;
}
+/**
+ * This gets called while closing uio device file.
+ */
static int
igbuio_pci_release(struct uio_info *info, struct inode *inode)
{
struct rte_uio_pci_dev *udev = info->priv;
struct pci_dev *dev = udev->pdev;
+ if (udev->state == RTE_UDEV_REMOVED) {
+ mutex_destroy(&udev->lock);
+ igbuio_pci_release_iomem(&udev->info);
+ pci_disable_device(dev);
+ pci_set_drvdata(dev, NULL);
+ kfree(udev);
+ return 0;
+ }
+
mutex_lock(&udev->lock);
if (--udev->refcnt > 0) {
mutex_unlock(&udev->lock);
@@ -356,7 +391,7 @@ igbuio_pci_release(struct uio_info *info, struct inode
*inode)
/* stop the device from further DMA */
pci_clear_master(dev);
-
+ udev->state = RTE_UDEV_RELEASED;
mutex_unlock(&udev->lock);
return 0;
}
@@ -414,18 +449,6 @@ igbuio_pci_setup_ioport(struct pci_dev *dev, struct
uio_info *info,
return 0;
}
-/* Unmap previously ioremap'd resources */
-static void
-igbuio_pci_release_iomem(struct uio_info *info)
-{
- int i;
-
- for (i = 0; i < MAX_UIO_MAPS; i++) {
- if (info->mem[i].internal_addr)
- iounmap(info->mem[i].internal_addr);
- }
-}
-
static int
igbuio_setup_bars(struct pci_dev *dev, struct uio_info *info)
{
@@ -562,6 +585,9 @@ igbuio_pci_probe(struct pci_dev *dev, const struct
pci_device_id *id)
(unsigned long long)map_dma_addr, map_addr);
}
+ mutex_lock(&udev->lock);
+ udev->state = RTE_UDEV_PROBED;
+ mutex_unlock(&udev->lock);
return 0;
fail_remove_group:
@@ -579,6 +605,21 @@ static void
igbuio_pci_remove(struct pci_dev *dev)
{
struct rte_uio_pci_dev *udev = pci_get_drvdata(dev);
+ struct pci_dev *pdev = udev->pdev;
+ int ret;
+
+ /* handle unexpected removal */
+ if (udev->state == RTE_UDEV_OPENNED ||
+ (&pdev->dev.kobj)->state_remove_uevent_sent == 1) {
+ dev_notice(&dev->dev, "Unexpected removal!\n");
+ ret = igbuio_pci_release(&udev->info, NULL);
+ if (ret)
+ return;
+ mutex_lock(&udev->lock);
+ udev->state = RTE_UDEV_REMOVED;
+ mutex_unlock(&udev->lock);
+ return;
+ }
mutex_destroy(&udev->lock);
sysfs_remove_group(&dev->dev.kobj, &dev_attr_grp);
--
2.7.4
