[PATCH 09/10] vfio/pci: Replace uses of vfio_device_data() with container_of

From: Jason Gunthorpe <jgg@nvidia.com>
To: Alex Williamson <alex.williamson@redhat.com>,
	Cornelia Huck <cohuck@redhat.com>,
	kvm@vger.kernel.org
Cc: "Raj, Ashok" <ashok.raj@intel.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Daniel Vetter <daniel@ffwll.ch>, Christoph Hellwig <hch@lst.de>,
	Leon Romanovsky <leonro@nvidia.com>,
	Max Gurtovoy <mgurtovoy@nvidia.com>,
	Tarun Gupta <targupta@nvidia.com>
Subject: [PATCH 09/10] vfio/pci: Replace uses of vfio_device_data() with container_of
Date: Tue,  9 Mar 2021 17:38:51 -0400	[thread overview]
Message-ID: <9-v1-7355d38b9344+17481-vfio1_jgg@nvidia.com> (raw)
In-Reply-To: <0-v1-7355d38b9344+17481-vfio1_jgg@nvidia.com>

This tidies a few confused places that think they can have a refcount on
the vfio_device but the device_data could be NULL, that isn't possible by
design.

Most of the change falls out when struct vfio_devices is updated to just
store the struct vfio_pci_device itself. This wasn't possible before
because there was no easy way to get from the 'struct vfio_pci_device' to
the 'struct vfio_device' to put back the refcount.

Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
 drivers/vfio/pci/vfio_pci.c | 45 ++++++++++++-------------------------
 1 file changed, 14 insertions(+), 31 deletions(-)

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index af5696a96a76e0..4b0d60f7602e40 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -534,7 +534,7 @@ static struct vfio_pci_device *get_pf_vdev(struct vfio_pci_device *vdev,
 		return NULL;
 	}
 
-	return vfio_device_data(*pf_dev);
+	return container_of(*pf_dev, struct vfio_pci_device, vdev);
 }
 
 static void vfio_pci_vf_token_user_add(struct vfio_pci_device *vdev, int val)
@@ -794,7 +794,7 @@ int vfio_pci_register_dev_region(struct vfio_pci_device *vdev,
 }
 
 struct vfio_devices {
-	struct vfio_device **devices;
+	struct vfio_pci_device **devices;
 	int cur_index;
 	int max_index;
 };
@@ -1283,9 +1283,7 @@ static long vfio_pci_ioctl(struct vfio_device *core_vdev,
 			goto hot_reset_release;
 
 		for (; mem_idx < devs.cur_index; mem_idx++) {
-			struct vfio_pci_device *tmp;
-
-			tmp = vfio_device_data(devs.devices[mem_idx]);
+			struct vfio_pci_device *tmp = devs.devices[mem_idx];
 
 			ret = down_write_trylock(&tmp->memory_lock);
 			if (!ret) {
@@ -1300,17 +1298,13 @@ static long vfio_pci_ioctl(struct vfio_device *core_vdev,
 
 hot_reset_release:
 		for (i = 0; i < devs.cur_index; i++) {
-			struct vfio_device *device;
-			struct vfio_pci_device *tmp;
-
-			device = devs.devices[i];
-			tmp = vfio_device_data(device);
+			struct vfio_pci_device *tmp = devs.devices[i];
 
 			if (i < mem_idx)
 				up_write(&tmp->memory_lock);
 			else
 				mutex_unlock(&tmp->vma_lock);
-			vfio_device_put(device);
+			vfio_device_put(&tmp->vdev);
 		}
 		kfree(devs.devices);
 
@@ -2094,11 +2088,7 @@ static pci_ers_result_t vfio_pci_aer_err_detected(struct pci_dev *pdev,
 	if (device == NULL)
 		return PCI_ERS_RESULT_DISCONNECT;
 
-	vdev = vfio_device_data(device);
-	if (vdev == NULL) {
-		vfio_device_put(device);
-		return PCI_ERS_RESULT_DISCONNECT;
-	}
+	vdev = container_of(device, struct vfio_pci_device, vdev);
 
 	mutex_lock(&vdev->igate);
 
@@ -2114,7 +2104,6 @@ static pci_ers_result_t vfio_pci_aer_err_detected(struct pci_dev *pdev,
 
 static int vfio_pci_sriov_configure(struct pci_dev *pdev, int nr_virtfn)
 {
-	struct vfio_pci_device *vdev;
 	struct vfio_device *device;
 	int ret = 0;
 
@@ -2127,12 +2116,6 @@ static int vfio_pci_sriov_configure(struct pci_dev *pdev, int nr_virtfn)
 	if (!device)
 		return -ENODEV;
 
-	vdev = vfio_device_data(device);
-	if (!vdev) {
-		vfio_device_put(device);
-		return -ENODEV;
-	}
-
 	if (nr_virtfn == 0)
 		pci_disable_sriov(pdev);
 	else
@@ -2192,7 +2175,7 @@ static int vfio_pci_reflck_find(struct pci_dev *pdev, void *data)
 		return 0;
 	}
 
-	vdev = vfio_device_data(device);
+	vdev = container_of(device, struct vfio_pci_device, vdev);
 
 	if (vdev->reflck) {
 		vfio_pci_reflck_get(vdev->reflck);
@@ -2254,7 +2237,7 @@ static int vfio_pci_get_unused_devs(struct pci_dev *pdev, void *data)
 		return -EBUSY;
 	}
 
-	vdev = vfio_device_data(device);
+	vdev = container_of(device, struct vfio_pci_device, vdev);
 
 	/* Fault if the device is not unused */
 	if (vdev->refcnt) {
@@ -2262,7 +2245,7 @@ static int vfio_pci_get_unused_devs(struct pci_dev *pdev, void *data)
 		return -EBUSY;
 	}
 
-	devs->devices[devs->cur_index++] = device;
+	devs->devices[devs->cur_index++] = vdev;
 	return 0;
 }
 
@@ -2284,7 +2267,7 @@ static int vfio_pci_try_zap_and_vma_lock_cb(struct pci_dev *pdev, void *data)
 		return -EBUSY;
 	}
 
-	vdev = vfio_device_data(device);
+	vdev = container_of(device, struct vfio_pci_device, vdev);
 
 	/*
 	 * Locking multiple devices is prone to deadlock, runaway and
@@ -2295,7 +2278,7 @@ static int vfio_pci_try_zap_and_vma_lock_cb(struct pci_dev *pdev, void *data)
 		return -EBUSY;
 	}
 
-	devs->devices[devs->cur_index++] = device;
+	devs->devices[devs->cur_index++] = vdev;
 	return 0;
 }
 
@@ -2343,7 +2326,7 @@ static void vfio_pci_try_bus_reset(struct vfio_pci_device *vdev)
 
 	/* Does at least one need a reset? */
 	for (i = 0; i < devs.cur_index; i++) {
-		tmp = vfio_device_data(devs.devices[i]);
+		tmp = devs.devices[i];
 		if (tmp->needs_reset) {
 			ret = pci_reset_bus(vdev->pdev);
 			break;
@@ -2352,7 +2335,7 @@ static void vfio_pci_try_bus_reset(struct vfio_pci_device *vdev)
 
 put_devs:
 	for (i = 0; i < devs.cur_index; i++) {
-		tmp = vfio_device_data(devs.devices[i]);
+		tmp = devs.devices[i];
 
 		/*
 		 * If reset was successful, affected devices no longer need
@@ -2368,7 +2351,7 @@ static void vfio_pci_try_bus_reset(struct vfio_pci_device *vdev)
 				vfio_pci_set_power_state(tmp, PCI_D3hot);
 		}
 
-		vfio_device_put(devs.devices[i]);
+		vfio_device_put(&tmp->vdev);
 	}
 
 	kfree(devs.devices);
-- 
2.30.1

