6cc8e74308
Currently, loop device has only one global lock: loop_ctl_mutex. This becomes hot in scenarios where many loop devices are used. Scale it by introducing per-device lock: lo_mutex that protects modifications of all fields in struct loop_device. Keep loop_ctl_mutex to protect global data: loop_index_idr, loop_lookup, loop_add. The new lock ordering requirement is that loop_ctl_mutex must be taken before lo_mutex. Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com> Reviewed-by: Petr Vorel <pvorel@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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.