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Subject[FSAIO][PATCH 3/8] Routines to initialize and test a wait bit key

init_wait_bit_key() initializes the key field in an already
allocated wait bit structure, useful for async wait bit support.
Also separate out the wait bit test to a common routine which
can be used by different kinds of wakeup callbacks.

Signed-off-by: Suparna Bhattacharya <suparna@in.ibm.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
---
linux-2.6.20-rc1-root/include/linux/wait.h | 24 ++++++++++++++++++++++++
linux-2.6.20-rc1-root/kernel/wait.c | 11 ++---------
2 files changed, 26 insertions(+), 9 deletions(-)
diff -puN include/linux/wait.h~init-wait-bit-key include/linux/wait.h
--- linux-2.6.20-rc1/include/linux/wait.h~init-wait-bit-key 2006-12-21 08:45:46.000000000 +0530
+++ linux-2.6.20-rc1-root/include/linux/wait.h 2006-12-21 08:45:46.000000000 +0530
@@ -108,6 +108,17 @@ static inline int waitqueue_active(wait_
return !list_empty(&q->task_list);
}

+static inline int test_wait_bit_key(wait_queue_t *wait,
+ struct wait_bit_key *key)
+{
+ struct wait_bit_queue *wait_bit
+ = container_of(wait, struct wait_bit_queue, wait);
+
+ return (wait_bit->key.flags == key->flags &&
+ wait_bit->key.bit_nr == key->bit_nr &&
+ !test_bit(key->bit_nr, key->flags));
+}
+
/*
* Used to distinguish between sync and async io wait context:
* sync i/o typically specifies a NULL wait queue entry or a wait
@@ -416,6 +427,19 @@ int wake_bit_function(wait_queue_t *wait
INIT_LIST_HEAD(&(wait)->task_list); \
} while (0)

+#define init_wait_bit_key(waitbit, word, bit) \
+ do { \
+ (waitbit)->key.flags = word; \
+ (waitbit)->key.bit_nr = bit; \
+ } while (0)
+
+#define init_wait_bit_task(waitbit, tsk) \
+ do { \
+ (waitbit)->wait.private = tsk; \
+ (waitbit)->wait.func = wake_bit_function; \
+ INIT_LIST_HEAD(&(waitbit)->wait.task_list); \
+ } while (0)
+
/**
* wait_on_bit - wait for a bit to be cleared
* @word: the word being waited on, a kernel virtual address
diff -puN kernel/wait.c~init-wait-bit-key kernel/wait.c
--- linux-2.6.20-rc1/kernel/wait.c~init-wait-bit-key 2006-12-21 08:45:46.000000000 +0530
+++ linux-2.6.20-rc1-root/kernel/wait.c 2006-12-28 09:32:44.000000000 +0530
@@ -139,16 +139,9 @@ EXPORT_SYMBOL(autoremove_wake_function);

int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *arg)
{
- struct wait_bit_key *key = arg;
- struct wait_bit_queue *wait_bit
- = container_of(wait, struct wait_bit_queue, wait);
-
- if (wait_bit->key.flags != key->flags ||
- wait_bit->key.bit_nr != key->bit_nr ||
- test_bit(key->bit_nr, key->flags))
+ if (!test_wait_bit_key(wait, arg))
return 0;
- else
- return autoremove_wake_function(wait, mode, sync, key);
+ return autoremove_wake_function(wait, mode, sync, arg);
}
EXPORT_SYMBOL(wake_bit_function);

_
--
Suparna Bhattacharya (suparna@in.ibm.com)
Linux Technology Center
IBM Software Lab, India
-
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