07ccd6bdaf
Currently we create a new mmap_offset for every call to mmap_offset_ioctl. This exposes ourselves to an abusive client that may simply create new mmap_offsets ad infinitum, which will exhaust physical memory and the virtual address space. In addition to the exhaustion, a very long linear list of mmap_offsets causes other clients using the object to incur long list walks -- these long lists can also be generated by simply having many clients generate their own mmap_offset. However, we can simply use the drm_vma_node itself to manage the file association (allow/revoke) dropping our need to keep an mmo per-file. Then if we keep a small rbtree of per-type mmap_offsets, we can lookup duplicate requests quickly. Fixes:cc662126b4("drm/i915: Introduce DRM_I915_GEM_MMAP_OFFSET") Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Abdiel Janulgue <abdiel.janulgue@linux.intel.com> Reviewed-by: Abdiel Janulgue <abdiel.janulgue@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200120104924.4000706-3-chris@chris-wilson.co.uk (cherry picked from commit7865559872) Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
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.