Revision 77788775c7132a8d93c6930ab1bd84fc743c7cb7 authored by Jens Axboe on 29 December 2020, 17:50:46 UTC, committed by Jens Axboe on 29 December 2020, 18:00:36 UTC
If we COW the identity, we assume that ->mm never changes. But this
isn't true of multiple processes end up sharing the ring. Hence treat
id->mm like like any other process compontent when it comes to the
identity mapping. This is pretty trivial, just moving the existing grab
into io_grab_identity(), and including a check for the match.

Cc: stable@vger.kernel.org # 5.10
Fixes: 1e6fa5216a0e ("io_uring: COW io_identity on mismatch")
Reported-by: Christian Brauner <christian.brauner@ubuntu.com>:
Tested-by: Christian Brauner <christian.brauner@ubuntu.com>:
Signed-off-by: Jens Axboe <axboe@kernel.dk>
1 parent 5c8fe58
Raw File
w1_ds2406.rst
=======================
w1_ds2406 kernel driver
=======================

Supported chips:

  * Maxim DS2406 (and other family 0x12) addressable switches

Author: Scott Alfter <scott@alfter.us>

Description
-----------

The w1_ds2406 driver allows connected devices to be switched on and off.
These chips also provide 128 bytes of OTP EPROM, but reading/writing it is
not supported.  In TSOC-6 form, the DS2406 provides two switch outputs and
can be provided with power on a dedicated input.  In TO-92 form, it provides
one output and uses parasitic power only.

The driver provides two sysfs files.  state is readable; it gives the
current state of each switch, with PIO A in bit 0 and PIO B in bit 1.  The
driver ORs this state with 0x30, so shell scripts get an ASCII 0/1/2/3 to
work with.  output is writable; bits 0 and 1 control PIO A and B,
respectively.  Bits 2-7 are ignored, so it's safe to write ASCII data.

CRCs are checked on read and write.  Failed checks cause an I/O error to be
returned.  On a failed write, the switch status is not changed.
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