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authorWolfram Sang <wsa+renesas@sang-engineering.com>2019-04-25 16:19:47 +0200
committerWolfram Sang <wsa@the-dreams.de>2019-05-03 15:25:00 +0200
commit4db61c2a16fce2ef85d82751de4ba43a39347cfb (patch)
tree51a9594eadc68b7fc923d3c838689333f94bc035
parentd00afd5ede1c29a6dc59be2d7fb7d6ef28eb85c5 (diff)
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+
-rw-r--r--drivers/i2c/i2c-core-base.c5
-rw-r--r--include/linux/i2c.h3
2 files changed, 6 insertions, 2 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;
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 03755d4c9229..be27062f8ed1 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -694,7 +694,8 @@ struct i2c_adapter {
int retries;
struct device dev; /* the adapter device */
unsigned long locked_flags; /* owned by the I2C core */
-#define I2C_ALF_IS_SUSPENDED 0
+#define I2C_ALF_IS_SUSPENDED 0
+#define I2C_ALF_SUSPEND_REPORTED 1
int nr;
char name[48];