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f16bd3dda2
There are two kinds of locking sequence.
One is in the thread which is started by vfio ioctl to do
the iommu unmapping. The locking sequence is:
down_read(&group_lock) ----> mutex_lock(&cached_lock)
The other is in the vfio release thread which will unpin all
the cached pages. The lock sequence is:
mutex_lock(&cached_lock) ---> down_read(&group_lock)
And, the cache_lock is used to protect the rb tree of the cache
node and doing vfio unpin doesn't require this lock. Move the
vfio unpin out of the cache_lock protected region.
v2:
- use for style instead of do{}while(1). (Zhenyu)
Fixes: f30437c5e7 ("drm/i915/gvt: add KVMGT support")
Signed-off-by: Chuanxiao Dong <chuanxiao.dong@intel.com>
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: stable@vger.kernel.org # v4.10+
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.