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Subject: Re: [PATCH] Bluetooth: btrtl: Use kvmalloc for FW allocations
From:   Marcel Holtmann <marcel@holtmann.org>
In-Reply-To: <20200124171535.32919-1-maxtram95@gmail.com>
Date:   Fri, 24 Jan 2020 19:58:31 +0100
Cc:     Johan Hedberg <johan.hedberg@gmail.com>,
        linux-bluetooth@vger.kernel.org,
        Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
        Carlo Caione <carlo@endlessm.com>
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References: <20200124171535.32919-1-maxtram95@gmail.com>
To:     Maxim Mikityanskiy <maxtram95@gmail.com>
Sender: linux-bluetooth-owner@vger.kernel.org
Precedence: bulk

Hi Maxim,

> 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>
> ---
> drivers/bluetooth/btrtl.c | 20 +++++++++++---------
> 1 file changed, 11 insertions(+), 9 deletions(-)

patch has been applied to bluetooth-next tree.

Regards

Marcel