diff options
Diffstat (limited to 'include/linux/iopoll.h')
| -rw-r--r-- | include/linux/iopoll.h | 136 |
1 files changed, 97 insertions, 39 deletions
diff --git a/include/linux/iopoll.h b/include/linux/iopoll.h index 91324c331a4b..bdd2e0652bc3 100644 --- a/include/linux/iopoll.h +++ b/include/linux/iopoll.h @@ -14,62 +14,64 @@ #include <linux/io.h> /** - * read_poll_timeout - Periodically poll an address until a condition is - * met or a timeout occurs - * @op: accessor function (takes @args as its arguments) - * @val: Variable to read the value into - * @cond: Break condition (usually involving @val) - * @sleep_us: Maximum time to sleep between reads in us (0 tight-loops). Please - * read usleep_range() function description for details and + * poll_timeout_us - Periodically poll and perform an operation until + * a condition is met or a timeout occurs + * + * @op: Operation + * @cond: Break condition + * @sleep_us: Maximum time to sleep between operations in us (0 tight-loops). + * Please read usleep_range() function description for details and * limitations. * @timeout_us: Timeout in us, 0 means never timeout - * @sleep_before_read: if it is true, sleep @sleep_us before read. - * @args: arguments for @op poll + * @sleep_before_op: if it is true, sleep @sleep_us before operation. * * When available, you'll probably want to use one of the specialized * macros defined below rather than this macro directly. * - * Returns: 0 on success and -ETIMEDOUT upon a timeout. In either - * case, the last read value at @args is stored in @val. Must not + * Returns: 0 on success and -ETIMEDOUT upon a timeout. Must not * be called from atomic context if sleep_us or timeout_us are used. */ -#define read_poll_timeout(op, val, cond, sleep_us, timeout_us, \ - sleep_before_read, args...) \ +#define poll_timeout_us(op, cond, sleep_us, timeout_us, sleep_before_op) \ ({ \ u64 __timeout_us = (timeout_us); \ unsigned long __sleep_us = (sleep_us); \ ktime_t __timeout = ktime_add_us(ktime_get(), __timeout_us); \ + int ___ret; \ might_sleep_if((__sleep_us) != 0); \ - if (sleep_before_read && __sleep_us) \ + if ((sleep_before_op) && __sleep_us) \ usleep_range((__sleep_us >> 2) + 1, __sleep_us); \ for (;;) { \ - (val) = op(args); \ - if (cond) \ + bool __expired = __timeout_us && \ + ktime_compare(ktime_get(), __timeout) > 0; \ + /* guarantee 'op' and 'cond' are evaluated after timeout expired */ \ + barrier(); \ + op; \ + if (cond) { \ + ___ret = 0; \ break; \ - if (__timeout_us && \ - ktime_compare(ktime_get(), __timeout) > 0) { \ - (val) = op(args); \ + } \ + if (__expired) { \ + ___ret = -ETIMEDOUT; \ break; \ } \ if (__sleep_us) \ usleep_range((__sleep_us >> 2) + 1, __sleep_us); \ cpu_relax(); \ } \ - (cond) ? 0 : -ETIMEDOUT; \ + ___ret; \ }) /** - * read_poll_timeout_atomic - Periodically poll an address until a condition is - * met or a timeout occurs - * @op: accessor function (takes @args as its arguments) - * @val: Variable to read the value into - * @cond: Break condition (usually involving @val) - * @delay_us: Time to udelay between reads in us (0 tight-loops). Please - * read udelay() function description for details and + * poll_timeout_us_atomic - Periodically poll and perform an operation until + * a condition is met or a timeout occurs + * + * @op: Operation + * @cond: Break condition + * @delay_us: Time to udelay between operations in us (0 tight-loops). + * Please read udelay() function description for details and * limitations. * @timeout_us: Timeout in us, 0 means never timeout - * @delay_before_read: if it is true, delay @delay_us before read. - * @args: arguments for @op poll + * @delay_before_op: if it is true, delay @delay_us before operation. * * This macro does not rely on timekeeping. Hence it is safe to call even when * timekeeping is suspended, at the expense of an underestimation of wall clock @@ -78,27 +80,32 @@ * When available, you'll probably want to use one of the specialized * macros defined below rather than this macro directly. * - * Returns: 0 on success and -ETIMEDOUT upon a timeout. In either - * case, the last read value at @args is stored in @val. + * Returns: 0 on success and -ETIMEDOUT upon a timeout. */ -#define read_poll_timeout_atomic(op, val, cond, delay_us, timeout_us, \ - delay_before_read, args...) \ +#define poll_timeout_us_atomic(op, cond, delay_us, timeout_us, \ + delay_before_op) \ ({ \ u64 __timeout_us = (timeout_us); \ s64 __left_ns = __timeout_us * NSEC_PER_USEC; \ unsigned long __delay_us = (delay_us); \ u64 __delay_ns = __delay_us * NSEC_PER_USEC; \ - if (delay_before_read && __delay_us) { \ + int ___ret; \ + if ((delay_before_op) && __delay_us) { \ udelay(__delay_us); \ if (__timeout_us) \ __left_ns -= __delay_ns; \ } \ for (;;) { \ - (val) = op(args); \ - if (cond) \ + bool __expired = __timeout_us && __left_ns < 0; \ + /* guarantee 'op' and 'cond' are evaluated after timeout expired */ \ + barrier(); \ + op; \ + if (cond) { \ + ___ret = 0; \ break; \ - if (__timeout_us && __left_ns < 0) { \ - (val) = op(args); \ + } \ + if (__expired) { \ + ___ret = -ETIMEDOUT; \ break; \ } \ if (__delay_us) { \ @@ -110,10 +117,61 @@ if (__timeout_us) \ __left_ns--; \ } \ - (cond) ? 0 : -ETIMEDOUT; \ + ___ret; \ }) /** + * read_poll_timeout - Periodically poll an address until a condition is + * met or a timeout occurs + * @op: accessor function (takes @args as its arguments) + * @val: Variable to read the value into + * @cond: Break condition (usually involving @val) + * @sleep_us: Maximum time to sleep between reads in us (0 tight-loops). Please + * read usleep_range() function description for details and + * limitations. + * @timeout_us: Timeout in us, 0 means never timeout + * @sleep_before_read: if it is true, sleep @sleep_us before read. + * @args: arguments for @op poll + * + * When available, you'll probably want to use one of the specialized + * macros defined below rather than this macro directly. + * + * Returns: 0 on success and -ETIMEDOUT upon a timeout. In either + * case, the last read value at @args is stored in @val. Must not + * be called from atomic context if sleep_us or timeout_us are used. + */ +#define read_poll_timeout(op, val, cond, sleep_us, timeout_us, \ + sleep_before_read, args...) \ + poll_timeout_us((val) = op(args), cond, sleep_us, timeout_us, sleep_before_read) + +/** + * read_poll_timeout_atomic - Periodically poll an address until a condition is + * met or a timeout occurs + * @op: accessor function (takes @args as its arguments) + * @val: Variable to read the value into + * @cond: Break condition (usually involving @val) + * @delay_us: Time to udelay between reads in us (0 tight-loops). Please + * read udelay() function description for details and + * limitations. + * @timeout_us: Timeout in us, 0 means never timeout + * @delay_before_read: if it is true, delay @delay_us before read. + * @args: arguments for @op poll + * + * This macro does not rely on timekeeping. Hence it is safe to call even when + * timekeeping is suspended, at the expense of an underestimation of wall clock + * time, which is rather minimal with a non-zero delay_us. + * + * When available, you'll probably want to use one of the specialized + * macros defined below rather than this macro directly. + * + * Returns: 0 on success and -ETIMEDOUT upon a timeout. In either + * case, the last read value at @args is stored in @val. + */ +#define read_poll_timeout_atomic(op, val, cond, sleep_us, timeout_us, \ + sleep_before_read, args...) \ + poll_timeout_us_atomic((val) = op(args), cond, sleep_us, timeout_us, sleep_before_read) + +/** * readx_poll_timeout - Periodically poll an address until a condition is met or a timeout occurs * @op: accessor function (takes @addr as its only argument) * @addr: Address to poll |