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kernel: pipes: use wait queue walker to build list

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Uses the new z_sched_waitq_walk() routine to walk the pipe's wait
queue to build a list of waiting threads that will be used for
the data transfer.

This method is preferred over the previous as it ensures that
wait queue is safely traversed.

Signed-off-by: Peter Mitsis <peter.mitsis@intel.com>
This commit is contained in:
Peter Mitsis 2023-01-05 13:52:03 -05:00 committed by Stephanos Ioannidis
parent ca58339e16
commit 0037712e68
1 changed files with 33 additions and 13 deletions
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46
kernel/pipes.c
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@ -21,6 +21,12 @@
#include <kernel_internal.h>
#include <zephyr/sys/check.h>
struct waitq_walk_data {
sys_dlist_t *list;
size_t bytes_requested;
size_t bytes_available;
};
static int pipe_get_internal(k_spinlock_key_t key, struct k_pipe *pipe,
void *data, size_t bytes_to_read,
size_t *bytes_read, size_t min_xfer,
@ -200,6 +206,27 @@ static size_t pipe_xfer(unsigned char *dest, size_t dest_size,
return num_bytes;
}
/**
* @brief Callback routine used to populate wait list
*
* @return 1 to stop further walking; 0 to continue walking
*/
static int pipe_walk_op(struct k_thread *thread, void *data)
{
struct waitq_walk_data *walk_data = data;
struct _pipe_desc *desc = (struct _pipe_desc *)thread->base.swap_data;
sys_dlist_append(walk_data->list, &desc->node);
walk_data->bytes_available += desc->bytes_to_xfer;
if (walk_data->bytes_available >= walk_data->bytes_requested) {
return 1;
}
return 0;
}
/**
* @brief Popluate pipe descriptors for copying to/from waiters' buffers
*
@ -213,22 +240,15 @@ static size_t pipe_waiter_list_populate(sys_dlist_t *list,
_wait_q_t *wait_q,
size_t bytes_to_xfer)
{
struct k_thread *thread;
struct _pipe_desc *curr;
size_t num_bytes = 0U;
struct waitq_walk_data walk_data;
_WAIT_Q_FOR_EACH(wait_q, thread) {
curr = (struct _pipe_desc *)thread->base.swap_data;
walk_data.list = list;
walk_data.bytes_requested = bytes_to_xfer;
walk_data.bytes_available = 0;
sys_dlist_append(list, &curr->node);
(void) z_sched_waitq_walk(wait_q, pipe_walk_op, &walk_data);
num_bytes += curr->bytes_to_xfer;
if (num_bytes >= bytes_to_xfer) {
break;
}
}
return num_bytes;
return walk_data.bytes_available;
}
/**