c139ca42f5
Let's add a simple reproducer for a scenario where GUP-fast could succeed on secretmem folios, making vmsplice() succeed instead of failing. The reproducer is based on a reproducer [1] by Miklos Szeredi. We want to perform two tests: vmsplice() when a fresh page was just faulted in, and vmsplice() on an existing page after munmap() that would drain certain LRU caches/batches in the kernel. In an ideal world, we could use fallocate(FALLOC_FL_PUNCH_HOLE) / MADV_REMOVE to remove any existing page. As that is currently not possible, run the test before any other tests that would allocate memory in the secretmem fd. Perform the ftruncate() only once, and check the return value. [1] https://lkml.kernel.org/r/CAJfpegt3UCsMmxd0taOY11Uaw5U=eS1fE5dn0wZX3HF0oy8-oQ@mail.gmail.com Link: https://lkml.kernel.org/r/20240326143210.291116-3-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Miklos Szeredi <mszeredi@redhat.com> Cc: xingwei lee <xrivendell7@gmail.com> Cc: yue sun <samsun1006219@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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 reStructuredText 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.