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Commit 24da3cc0 authored by Bartosz Golaszewski's avatar Bartosz Golaszewski Committed by Wolfram Sang
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eeprom: at24: tweak the loop_until_timeout() macro 



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: default avatarWolfram Sang <wsa@the-dreams.de>
Signed-off-by: default avatarBartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent 0b813658

drivers/misc/eeprom/at24.c

+4 −4
Original line number Diff line number Diff line
@@ -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[] = {