@@ -116,7 +116,8 @@ MODULE_PARM_DESC(write_timeout, "Time (in ms) to try writes (default 25)");
/*
* Both reads and writes fail if the previous write didn't complete yet. This
* macro loops a few times waiting at least long enough for one entire page
- * write to work.
+ * write to work while making sure that at least one iteration is run before
+ * checking the break condition.
*
* It takes two parameters: a variable in which the future timeout in jiffies
* will be stored and a temporary variable holding the time of the last
@@ -124,9 +125,8 @@ MODULE_PARM_DESC(write_timeout, "Time (in ms) to try writes (default 25)");
* holding at least 32 bits.
*/
#define loop_until_timeout(tout, op_time) \
- for (tout = jiffies + msecs_to_jiffies(write_timeout), \
- op_time = jiffies; \
- time_before(op_time, tout); \
+ for (tout = jiffies + msecs_to_jiffies(write_timeout), op_time = 0; \
+ op_time ? time_before(op_time, tout) : true; \
usleep_range(1000, 1500), op_time = jiffies)
static const struct i2c_device_id at24_ids[] = {
loop_until_timeout() replaced a do {} while loop in the at24 driver with a for loop which, under certain circumstances (such as heavy load or low value of the write_timeout argument), can lead to the code in the loop never being executed. Make sure that at least one iteration of the code enclosed within loop_until_timeout() is always executed. Suggested-by: Wolfram Sang <wsa@the-dreams.de> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com> --- drivers/misc/eeprom/at24.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) -- 2.7.4 -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html