staging: rtl8192u: Fix sleep in atomic context bug in dm_fsync_timer_callback

stable inclusion
from stable-v5.10.137
commit 028c8632a2dcdc78b0489c19b0ecea3bb26bd4e2
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I60PLB

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=028c8632a2dcdc78b0489c19b0ecea3bb26bd4e2



--------------------------------

[ Upstream commit 6a0c0549 ]

There are sleep in atomic context bugs when dm_fsync_timer_callback is
executing. The root cause is that the memory allocation functions with
GFP_KERNEL or GFP_NOIO parameters are called in dm_fsync_timer_callback
which is a timer handler. The call paths that could trigger bugs are
shown below:

    (interrupt context)
dm_fsync_timer_callback
  write_nic_byte
    kzalloc(sizeof(data), GFP_KERNEL); //may sleep
    usb_control_msg
      kmalloc(.., GFP_NOIO); //may sleep
  write_nic_dword
    kzalloc(sizeof(data), GFP_KERNEL); //may sleep
    usb_control_msg
      kmalloc(.., GFP_NOIO); //may sleep

This patch uses delayed work to replace timer and moves the operations
that may sleep into the delayed work in order to mitigate bugs.

Fixes: 8fc8598e ("Staging: Added Realtek rtl8192u driver to staging")
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Link: https://lore.kernel.org/r/20220710103002.63283-1-duoming@zju.edu.cn


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Reviewed-by: Wei Li <liwei391@huawei.com>