0d3c75a693
commit d0b861653f8c16839c3035875b556afc4472f941 upstream.
When hcd->localmem_pool is non-null, localmem_pool is used to allocate
DMA memory. In this case, the dma address will be properly returned (in
dma_handle), and dma_mmap_coherent should be used to map this memory
into the user space. However, the current implementation uses
pfn_remap_range, which is supposed to map normal pages.
Instead of repeating the logic in the memory allocation function, this
patch introduces a more robust solution. Here, the type of allocated
memory is checked by testing whether dma_handle is properly set. If
dma_handle is properly returned, it means some DMA pages are allocated
and dma_mmap_coherent should be used to map them. Otherwise, normal
pages are allocated and pfn_remap_range should be called. This ensures
that the correct mmap functions are used consistently, independently
with logic details that determine which type of memory gets allocated.
Fixes: a0e710a7def4 ("USB: usbfs: fix mmap dma mismatch")
Cc: stable@vger.kernel.org
Signed-off-by: Ruihan Li <lrh2000@pku.edu.cn>
Link: https://lore.kernel.org/r/20230515130958.32471-3-lrh2000@pku.edu.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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 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.