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[ Upstream commit 268d3636df ]
Currently, kmemdup is applied to the firmware data, and it invokes
kmalloc under the hood. The firmware size and patch_length are big (more
than PAGE_SIZE), and on some low-end systems (like ASUS E202SA) kmalloc
may fail to allocate a contiguous chunk under high memory usage and
fragmentation:
Bluetooth: hci0: RTL: examining hci_ver=06 hci_rev=000a lmp_ver=06 lmp_subver=8821
Bluetooth: hci0: RTL: rom_version status=0 version=1
Bluetooth: hci0: RTL: loading rtl_bt/rtl8821a_fw.bin
kworker/u9:2: page allocation failure: order:4, mode:0x40cc0(GFP_KERNEL|__GFP_COMP), nodemask=(null),cpuset=/,mems_allowed=0
<stack trace follows>
As firmware load happens on each resume, Bluetooth will stop working
after several iterations, when the kernel fails to allocate an order-4
page.
This patch replaces kmemdup with kvmalloc+memcpy. It's not required to
have a contiguous chunk here, because it's not mapped to the device
directly.
Signed-off-by: Maxim Mikityanskiy <maxtram95@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Sasha Levin <sashal@kernel.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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.