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author | Richard Fitzgerald <rf@opensource.cirrus.com> | 2023-04-06 14:46:40 +0100 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-05-24 17:32:42 +0100 |
commit | 4e5e9da139c007dfc397a159093b4c4187ee67fa (patch) | |
tree | 0aa7b4b9eaeb80455d45ca82540a11488eb76a43 | |
parent | 60eb1afb4fb6f79d343844fc3549c8028e03b11e (diff) | |
download | linux-stable-4e5e9da139c007dfc397a159093b4c4187ee67fa.tar.gz linux-stable-4e5e9da139c007dfc397a159093b4c4187ee67fa.tar.bz2 linux-stable-4e5e9da139c007dfc397a159093b4c4187ee67fa.zip |
soundwire: bus: Fix unbalanced pm_runtime_put() causing usage count underflow
[ Upstream commit e9537962519e88969f5f69cd0571eb4f6984403c ]
This reverts commit
443a98e649b4 ("soundwire: bus: use pm_runtime_resume_and_get()")
Change calls to pm_runtime_resume_and_get() back to pm_runtime_get_sync().
This fixes a usage count underrun caused by doing a pm_runtime_put() even
though pm_runtime_resume_and_get() returned an error.
The three affected functions ignore -EACCES error from trying to get
pm_runtime, and carry on, including a put at the end of the function.
But pm_runtime_resume_and_get() does not increment the usage count if it
returns an error. So in the -EACCES case you must not call
pm_runtime_put().
The documentation for pm_runtime_get_sync() says:
"Consider using pm_runtime_resume_and_get() ... as this is likely to
result in cleaner code."
In this case I don't think it results in cleaner code because the
pm_runtime_put() at the end of the function would have to be conditional on
the return value from pm_runtime_resume_and_get() at the top of the
function.
pm_runtime_get_sync() doesn't have this problem because it always
increments the count, so always needs a put. The code can just flow through
and do the pm_runtime_put() unconditionally.
Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20230406134640.8582-1-rf@opensource.cirrus.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
-rw-r--r-- | drivers/soundwire/bus.c | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c index 76515c33e639..4fd221d0cc81 100644 --- a/drivers/soundwire/bus.c +++ b/drivers/soundwire/bus.c @@ -571,9 +571,11 @@ int sdw_nread(struct sdw_slave *slave, u32 addr, size_t count, u8 *val) { int ret; - ret = pm_runtime_resume_and_get(&slave->dev); - if (ret < 0 && ret != -EACCES) + ret = pm_runtime_get_sync(&slave->dev); + if (ret < 0 && ret != -EACCES) { + pm_runtime_put_noidle(&slave->dev); return ret; + } ret = sdw_nread_no_pm(slave, addr, count, val); @@ -595,9 +597,11 @@ int sdw_nwrite(struct sdw_slave *slave, u32 addr, size_t count, const u8 *val) { int ret; - ret = pm_runtime_resume_and_get(&slave->dev); - if (ret < 0 && ret != -EACCES) + ret = pm_runtime_get_sync(&slave->dev); + if (ret < 0 && ret != -EACCES) { + pm_runtime_put_noidle(&slave->dev); return ret; + } ret = sdw_nwrite_no_pm(slave, addr, count, val); @@ -1565,9 +1569,10 @@ static int sdw_handle_slave_alerts(struct sdw_slave *slave) sdw_modify_slave_status(slave, SDW_SLAVE_ALERT); - ret = pm_runtime_resume_and_get(&slave->dev); + ret = pm_runtime_get_sync(&slave->dev); if (ret < 0 && ret != -EACCES) { dev_err(&slave->dev, "Failed to resume device: %d\n", ret); + pm_runtime_put_noidle(&slave->dev); return ret; } |