diff options
| author | Jason Gunthorpe <jgg@nvidia.com> | 2022-09-08 21:44:58 +0300 |
|---|---|---|
| committer | Jason Gunthorpe <jgg@nvidia.com> | 2022-12-05 15:56:01 +0300 |
| commit | f794eec86c7cd9a340a66109e6f32f8659ff30fa (patch) | |
| tree | 33f1410da4f8786da6ca8de6609b491d135dd0a9 /drivers/vfio | |
| parent | 90337f526c98129b0b180fc52dc5f57d8e7a8614 (diff) | |
| download | linux-f794eec86c7cd9a340a66109e6f32f8659ff30fa.tar.xz | |
vfio: Simplify vfio_create_group()
The vfio.group_lock is now only used to serialize vfio_group creation and
destruction, we don't need a micro-optimization of searching, unlocking,
then allocating and searching again. Just hold the lock the whole time.
Grabbed from:
https://lore.kernel.org/kvm/20220922152338.2a2238fe.alex.williamson@redhat.com/
Link: https://lore.kernel.org/r/20221201145535.589687-2-yi.l.liu@intel.com
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Tested-by: Lixiao Yang <lixiao.yang@intel.com>
Tested-by: Yu He <yu.he@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Diffstat (limited to 'drivers/vfio')
| -rw-r--r-- | drivers/vfio/vfio_main.c | 33 |
1 files changed, 10 insertions, 23 deletions
diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c index 6d51b700764e..f913d862a386 100644 --- a/drivers/vfio/vfio_main.c +++ b/drivers/vfio/vfio_main.c @@ -143,10 +143,12 @@ EXPORT_SYMBOL_GPL(vfio_device_set_open_count); * Group objects - create, release, get, put, search */ static struct vfio_group * -__vfio_group_get_from_iommu(struct iommu_group *iommu_group) +vfio_group_get_from_iommu(struct iommu_group *iommu_group) { struct vfio_group *group; + lockdep_assert_held(&vfio.group_lock); + /* * group->iommu_group from the vfio.group_list cannot be NULL * under the vfio.group_lock. @@ -160,17 +162,6 @@ __vfio_group_get_from_iommu(struct iommu_group *iommu_group) return NULL; } -static struct vfio_group * -vfio_group_get_from_iommu(struct iommu_group *iommu_group) -{ - struct vfio_group *group; - - mutex_lock(&vfio.group_lock); - group = __vfio_group_get_from_iommu(iommu_group); - mutex_unlock(&vfio.group_lock); - return group; -} - static void vfio_group_release(struct device *dev) { struct vfio_group *group = container_of(dev, struct vfio_group, dev); @@ -225,6 +216,8 @@ static struct vfio_group *vfio_create_group(struct iommu_group *iommu_group, struct vfio_group *ret; int err; + lockdep_assert_held(&vfio.group_lock); + group = vfio_group_alloc(iommu_group, type); if (IS_ERR(group)) return group; @@ -237,26 +230,16 @@ static struct vfio_group *vfio_create_group(struct iommu_group *iommu_group, goto err_put; } - mutex_lock(&vfio.group_lock); - - /* Did we race creating this group? */ - ret = __vfio_group_get_from_iommu(iommu_group); - if (ret) - goto err_unlock; - err = cdev_device_add(&group->cdev, &group->dev); if (err) { ret = ERR_PTR(err); - goto err_unlock; + goto err_put; } list_add(&group->vfio_next, &vfio.group_list); - mutex_unlock(&vfio.group_lock); return group; -err_unlock: - mutex_unlock(&vfio.group_lock); err_put: put_device(&group->dev); return ret; @@ -467,7 +450,9 @@ static struct vfio_group *vfio_noiommu_group_alloc(struct device *dev, if (ret) goto out_put_group; + mutex_lock(&vfio.group_lock); group = vfio_create_group(iommu_group, type); + mutex_unlock(&vfio.group_lock); if (IS_ERR(group)) { ret = PTR_ERR(group); goto out_remove_device; @@ -516,9 +501,11 @@ static struct vfio_group *vfio_group_find_or_alloc(struct device *dev) return ERR_PTR(-EINVAL); } + mutex_lock(&vfio.group_lock); group = vfio_group_get_from_iommu(iommu_group); if (!group) group = vfio_create_group(iommu_group, VFIO_IOMMU); + mutex_unlock(&vfio.group_lock); /* The vfio_group holds a reference to the iommu_group */ iommu_group_put(iommu_group); |