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Subject[PATCH net-next 1/5] net: ipa: always use transaction IDs instead of lists
Date
In gsi_channel_trans_complete(), use the completed and pending IDs
to determine whether there are any transactions in completed state.

Similarly, in gsi_channel_trans_cancel_pending(), use the pending
and committed IDs to mark pending transactions cancelled. Rearrange
the logic a bit there for a simpler result.

This removes the only user of list_last_entry_or_null(), so get rid
of that macro.

Remove the temporary warnings added by the previous commit.

Signed-off-by: Alex Elder <elder@linaro.org>
---
drivers/net/ipa/gsi_private.h | 14 ---------
drivers/net/ipa/gsi_trans.c | 58 ++++++++++-------------------------
2 files changed, 16 insertions(+), 56 deletions(-)

diff --git a/drivers/net/ipa/gsi_private.h b/drivers/net/ipa/gsi_private.h
index 51bbc7a40dc2d..0b2516fa21b5d 100644
--- a/drivers/net/ipa/gsi_private.h
+++ b/drivers/net/ipa/gsi_private.h
@@ -16,20 +16,6 @@ struct gsi_channel;

#define GSI_RING_ELEMENT_SIZE 16 /* bytes; must be a power of 2 */

-/**
- * list_last_entry_or_null - get the last element from a list
- * @ptr: the list head to take the element from.
- * @type: the type of the struct this is embedded in.
- * @member: the name of the list_head within the struct.
- *
- * Note that if the list is empty, it returns NULL.
- */
-#define list_last_entry_or_null(ptr, type, member) ({ \
- struct list_head *head__ = (ptr); \
- struct list_head *pos__ = READ_ONCE(head__->prev); \
- pos__ != head__ ? list_entry(pos__, type, member) : NULL; \
-})
-
/**
* gsi_trans_move_complete() - Mark a GSI transaction completed
* @trans: Transaction to commit
diff --git a/drivers/net/ipa/gsi_trans.c b/drivers/net/ipa/gsi_trans.c
index 05ab4d052c68b..a131a4fbb53fc 100644
--- a/drivers/net/ipa/gsi_trans.c
+++ b/drivers/net/ipa/gsi_trans.c
@@ -239,22 +239,11 @@ struct gsi_trans *gsi_channel_trans_complete(struct gsi_channel *channel)
{
struct gsi_trans_info *trans_info = &channel->trans_info;
u16 trans_id = trans_info->completed_id;
- struct gsi_trans *trans;

- trans = list_first_entry_or_null(&trans_info->complete,
- struct gsi_trans, links);
-
- if (!trans) {
- WARN_ON(trans_id != trans_info->pending_id);
+ if (trans_id == trans_info->pending_id)
return NULL;
- }

- if (!WARN_ON(trans_id == trans_info->pending_id)) {
- trans_id %= channel->tre_count;
- WARN_ON(trans != &trans_info->trans[trans_id]);
- }
-
- return trans;
+ return &trans_info->trans[trans_id %= channel->tre_count];
}

/* Move a transaction from the allocated list to the committed list */
@@ -705,47 +694,32 @@ void gsi_trans_complete(struct gsi_trans *trans)
void gsi_channel_trans_cancel_pending(struct gsi_channel *channel)
{
struct gsi_trans_info *trans_info = &channel->trans_info;
- struct gsi_trans *trans;
- struct gsi_trans *first;
- struct gsi_trans *last;
- bool cancelled;
+ u16 trans_id = trans_info->pending_id;

/* channel->gsi->mutex is held by caller */
spin_lock_bh(&trans_info->spinlock);

- cancelled = !list_empty(&trans_info->pending);
- list_for_each_entry(trans, &trans_info->pending, links)
- trans->cancelled = true;
-
list_splice_tail_init(&trans_info->pending, &trans_info->complete);

- first = list_first_entry_or_null(&trans_info->complete,
- struct gsi_trans, links);
- last = list_last_entry_or_null(&trans_info->complete,
- struct gsi_trans, links);
-
spin_unlock_bh(&trans_info->spinlock);

+ /* If there are no pending transactions, we're done */
+ if (trans_id == trans_info->committed_id)
+ return;
+
+ /* Mark all pending transactions cancelled */
+ do {
+ struct gsi_trans *trans;
+
+ trans = &trans_info->trans[trans_id % channel->tre_count];
+ trans->cancelled = true;
+ } while (++trans_id != trans_info->committed_id);
+
/* All pending transactions are now completed */
- WARN_ON(cancelled != (trans_info->pending_id !=
- trans_info->committed_id));
-
trans_info->pending_id = trans_info->committed_id;

/* Schedule NAPI polling to complete the cancelled transactions */
- if (cancelled) {
- u16 trans_id;
-
- napi_schedule(&channel->napi);
-
- trans_id = trans_info->completed_id;
- trans = &trans_info->trans[trans_id % channel->tre_count];
- WARN_ON(trans != first);
-
- trans_id = trans_info->pending_id - 1;
- trans = &trans_info->trans[trans_id % channel->tre_count];
- WARN_ON(trans != last);
- }
+ napi_schedule(&channel->napi);
}

/* Issue a command to read a single byte from a channel */
--
2.34.1
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