7e8edae39f
When a driver needs to deal with a special buffer like a SG or a vmalloc buffer, it has to set up the PCM page ops explicitly for the corresponding helper function. This is rather error-prone and many people forgot or incorrectly used it. For simplifying the call patterns and avoiding such a potential bug, this patch enhances the PCM default mmap handler to check the (pre-)allocated buffer type and handles the page gracefully depending on the buffer type. If the PCM page ops is given, the ops is still used in a higher priority. The new code path is only for the default (NULL page ops) case. Link: https://lore.kernel.org/r/20191105080138.1260-4-tiwai@suse.de Signed-off-by: Takashi Iwai <tiwai@suse.de>
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.