diff options
| author | Benjamin Bara <benjamin.bara@skidata.com> | 2023-07-15 10:53:24 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-11-28 20:07:13 +0300 |
| commit | 185f3617adc8fe45e40489b458f03911f0dec46c (patch) | |
| tree | 6e48b6e005c3b6aab625f9f3ca1f8405038455cd /drivers/i2c | |
| parent | 59cb785919fd526d69fad6253ea18e57a4737c06 (diff) | |
| download | linux-185f3617adc8fe45e40489b458f03911f0dec46c.tar.xz | |
i2c: core: Run atomic i2c xfer when !preemptible
commit aa49c90894d06e18a1ee7c095edbd2f37c232d02 upstream.
Since bae1d3a05a8b, i2c transfers are non-atomic if preemption is
disabled. However, non-atomic i2c transfers require preemption (e.g. in
wait_for_completion() while waiting for the DMA).
panic() calls preempt_disable_notrace() before calling
emergency_restart(). Therefore, if an i2c device is used for the
restart, the xfer should be atomic. This avoids warnings like:
[ 12.667612] WARNING: CPU: 1 PID: 1 at kernel/rcu/tree_plugin.h:318 rcu_note_context_switch+0x33c/0x6b0
[ 12.676926] Voluntary context switch within RCU read-side critical section!
...
[ 12.742376] schedule_timeout from wait_for_completion_timeout+0x90/0x114
[ 12.749179] wait_for_completion_timeout from tegra_i2c_wait_completion+0x40/0x70
...
[ 12.994527] atomic_notifier_call_chain from machine_restart+0x34/0x58
[ 13.001050] machine_restart from panic+0x2a8/0x32c
Use !preemptible() instead, which is basically the same check as
pre-v5.2.
Fixes: bae1d3a05a8b ("i2c: core: remove use of in_atomic()")
Cc: stable@vger.kernel.org # v5.2+
Suggested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Acked-by: Wolfram Sang <wsa@kernel.org>
Reviewed-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Tested-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Benjamin Bara <benjamin.bara@skidata.com>
Link: https://lore.kernel.org/r/20230327-tegra-pmic-reboot-v7-2-18699d5dcd76@skidata.com
Signed-off-by: Lee Jones <lee@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/i2c')
| -rw-r--r-- | drivers/i2c/i2c-core.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/i2c/i2c-core.h b/drivers/i2c/i2c-core.h index 1247e6e6e975..05b8b8dfa9bd 100644 --- a/drivers/i2c/i2c-core.h +++ b/drivers/i2c/i2c-core.h @@ -29,7 +29,7 @@ int i2c_dev_irq_from_resources(const struct resource *resources, */ static inline bool i2c_in_atomic_xfer_mode(void) { - return system_state > SYSTEM_RUNNING && irqs_disabled(); + return system_state > SYSTEM_RUNNING && !preemptible(); } static inline int __i2c_lock_bus_helper(struct i2c_adapter *adap) |