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| author | Wolfram Sang <wsa+renesas@sang-engineering.com> | 2019-04-25 16:19:47 +0200 |
|---|---|---|
| committer | Wolfram Sang <wsa@the-dreams.de> | 2019-05-03 15:25:00 +0200 |
| commit | 4db61c2a16fce2ef85d82751de4ba43a39347cfb (patch) | |
| tree | 51a9594eadc68b7fc923d3c838689333f94bc035 /drivers/i2c | |
| parent | d00afd5ede1c29a6dc59be2d7fb7d6ef28eb85c5 (diff) | |
| download | linux-4db61c2a16fce2ef85d82751de4ba43a39347cfb.tar.gz linux-4db61c2a16fce2ef85d82751de4ba43a39347cfb.tar.bz2 linux-4db61c2a16fce2ef85d82751de4ba43a39347cfb.zip | |
i2c: core: ratelimit 'transfer when suspended' errors
There are two problems with WARN_ON() here. One: It is not ratelimited.
Two: We don't see which adapter was used when trying to transfer
something when already suspended. Implement a custom ratelimit once per
adapter and use dev_WARN there. This fixes both issues. Drawback is that
we don't see if multiple drivers are trying to transfer with the same
adapter while suspended. They need to be discovered one after the other
now. This is better than a high CPU load because a really broken driver
might try to resend endlessly.
Fixes: 9ac6cb5fbb17 ("i2c: add suspended flag and accessors for i2c adapters")
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@vger.kernel.org # v5.1+
Diffstat (limited to 'drivers/i2c')
| -rw-r--r-- | drivers/i2c/i2c-core-base.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c index 4e6300dc2c4e..f8e85983cb04 100644 --- a/drivers/i2c/i2c-core-base.c +++ b/drivers/i2c/i2c-core-base.c @@ -1867,8 +1867,11 @@ int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) if (WARN_ON(!msgs || num < 1)) return -EINVAL; - if (WARN_ON(test_bit(I2C_ALF_IS_SUSPENDED, &adap->locked_flags))) + if (test_bit(I2C_ALF_IS_SUSPENDED, &adap->locked_flags)) { + if (!test_and_set_bit(I2C_ALF_SUSPEND_REPORTED, &adap->locked_flags)) + dev_WARN(&adap->dev, "Transfer while suspended\n"); return -ESHUTDOWN; + } if (adap->quirks && i2c_check_for_quirks(adap, msgs, num)) return -EOPNOTSUPP; |