projects / thirdparty / kernel / stable-queue.git / blame
| Commit | Line | Data |
|---|---|---|
| 01e516ea GKH |
1 | From 4db61c2a16fce2ef85d82751de4ba43a39347cfb Mon Sep 17 00:00:00 2001 |
| 2 | From: Wolfram Sang <wsa+renesas@sang-engineering.com> | |
| 3 | Date: Thu, 25 Apr 2019 16:19:47 +0200 | |
| 4 | Subject: i2c: core: ratelimit 'transfer when suspended' errors | |
| 5 | ||
| 6 | From: Wolfram Sang <wsa+renesas@sang-engineering.com> | |
| 7 | ||
| 8 | commit 4db61c2a16fce2ef85d82751de4ba43a39347cfb upstream. | |
| 9 | ||
| 10 | There are two problems with WARN_ON() here. One: It is not ratelimited. | |
| 11 | Two: We don't see which adapter was used when trying to transfer | |
| 12 | something when already suspended. Implement a custom ratelimit once per | |
| 13 | adapter and use dev_WARN there. This fixes both issues. Drawback is that | |
| 14 | we don't see if multiple drivers are trying to transfer with the same | |
| 15 | adapter while suspended. They need to be discovered one after the other | |
| 16 | now. This is better than a high CPU load because a really broken driver | |
| 17 | might try to resend endlessly. | |
| 18 | ||
| 19 | Fixes: 9ac6cb5fbb17 ("i2c: add suspended flag and accessors for i2c adapters") | |
| 20 | Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> | |
| 21 | Reviewed-by: Simon Horman <horms+renesas@verge.net.au> | |
| 22 | Signed-off-by: Wolfram Sang <wsa@the-dreams.de> | |
| 23 | Cc: stable@vger.kernel.org # v5.1+ | |
| 24 | Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> | |
| 25 | ||
| 26 | --- | |
| 27 | drivers/i2c/i2c-core-base.c | 5 ++++- | |
| 28 | include/linux/i2c.h | 3 ++- | |
| 29 | 2 files changed, 6 insertions(+), 2 deletions(-) | |
| 30 | ||
| 31 | --- a/drivers/i2c/i2c-core-base.c | |
| 32 | +++ b/drivers/i2c/i2c-core-base.c | |
| 33 | @@ -1871,8 +1871,11 @@ int __i2c_transfer(struct i2c_adapter *a | |
| 34 | ||
| 35 | if (WARN_ON(!msgs || num < 1)) | |
| 36 | return -EINVAL; | |
| 37 | - if (WARN_ON(test_bit(I2C_ALF_IS_SUSPENDED, &adap->locked_flags))) | |
| 38 | + if (test_bit(I2C_ALF_IS_SUSPENDED, &adap->locked_flags)) { | |
| 39 | + if (!test_and_set_bit(I2C_ALF_SUSPEND_REPORTED, &adap->locked_flags)) | |
| 40 | + dev_WARN(&adap->dev, "Transfer while suspended\n"); | |
| 41 | return -ESHUTDOWN; | |
| 42 | + } | |
| 43 | ||
| 44 | if (adap->quirks && i2c_check_for_quirks(adap, msgs, num)) | |
| 45 | return -EOPNOTSUPP; | |
| 46 | --- a/include/linux/i2c.h | |
| 47 | +++ b/include/linux/i2c.h | |
| 48 | @@ -682,7 +682,8 @@ struct i2c_adapter { | |
| 49 | int retries; | |
| 50 | struct device dev; /* the adapter device */ | |
| 51 | unsigned long locked_flags; /* owned by the I2C core */ | |
| 52 | -#define I2C_ALF_IS_SUSPENDED 0 | |
| 53 | +#define I2C_ALF_IS_SUSPENDED 0 | |
| 54 | +#define I2C_ALF_SUSPEND_REPORTED 1 | |
| 55 | ||
| 56 | int nr; | |
| 57 | char name[48]; |