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net: ipa: use an array for transactions 

Transactions are always allocated one at a time.  The maximum number
of them we could ever need occurs if each TRE is assigned to a
transaction.  So a channel requires no more transactions than the
number of TREs in its transfer ring.  That number is known to be a
power-of-2 less than 65536.

The transaction pool abstraction is used for other things, but for
transactions we can use a simple array of transaction structures,
and use a free index to indicate which entry in the array is the
next one free for allocation.

By having the number of elements in the array be a power-of-2, we
can use an ever-incrementing 16-bit free index, and use it modulo
the array size.  Distinguish a "trans_id" (whose value can exceed
the number of entries in the transaction array) from a "trans_index"
(which is less than the number of entries).

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Alex Elder 2022-08-31 17:40:12 -05:00 committed by David S. Miller
parent a01105f174
commit 12382d1167
2 changed files with 20 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
drivers/net/ipa/gsi.h
View File

@ -82,7 +82,9 @@ struct gsi_trans_pool {
struct gsi_trans_info {
atomic_t tre_avail; /* TREs available for allocation */
struct gsi_trans_pool pool; /* transaction pool */
u16 free_id; /* first free trans in array */
struct gsi_trans *trans; /* transaction array */
struct gsi_trans **map; /* TRE -> transaction map */
struct gsi_trans_pool sg_pool; /* scatterlist pool */

29
drivers/net/ipa/gsi_trans.c
View File

@ -343,20 +343,22 @@ struct gsi_trans *gsi_channel_trans_alloc(struct gsi *gsi, u32 channel_id,
struct gsi_channel *channel = &gsi->channel[channel_id];
struct gsi_trans_info *trans_info;
struct gsi_trans *trans;
u16 trans_index;
if (WARN_ON(tre_count > channel->trans_tre_max))
return NULL;
trans_info = &channel->trans_info;
/* We reserve the TREs now, but consume them at commit time.
* If there aren't enough available, we're done.
*/
/* If we can't reserve the TREs for the transaction, we're done */
if (!gsi_trans_tre_reserve(trans_info, tre_count))
return NULL;
/* Allocate and initialize non-zero fields in the transaction */
trans = gsi_trans_pool_alloc(&trans_info->pool, 1);
trans_index = trans_info->free_id % channel->tre_count;
trans = &trans_info->trans[trans_index];
memset(trans, 0, sizeof(*trans));
/* Initialize non-zero fields in the transaction */
trans->gsi = gsi;
trans->channel_id = channel_id;
trans->rsvd_count = tre_count;
@ -367,6 +369,10 @@ struct gsi_trans *gsi_channel_trans_alloc(struct gsi *gsi, u32 channel_id,
sg_init_marker(trans->sgl, tre_count);
trans->direction = direction;
refcount_set(&trans->refcount, 1);
/* This free transaction will now be allocated */
trans_info->free_id++;
spin_lock_bh(&trans_info->spinlock);
@ -374,8 +380,6 @@ struct gsi_trans *gsi_channel_trans_alloc(struct gsi *gsi, u32 channel_id,
spin_unlock_bh(&trans_info->spinlock);
refcount_set(&trans->refcount, 1);
return trans;
}
@ -736,10 +740,11 @@ int gsi_channel_trans_init(struct gsi *gsi, u32 channel_id)
* modulo that number to determine the next one that's free.
* Transactions are allocated one at a time.
*/
ret = gsi_trans_pool_init(&trans_info->pool, sizeof(struct gsi_trans),
tre_max, 1);
if (ret)
trans_info->trans = kcalloc(tre_count, sizeof(*trans_info->trans),
GFP_KERNEL);
if (!trans_info->trans)
return -ENOMEM;
trans_info->free_id = 0; /* modulo channel->tre_count */
/* A completion event contains a pointer to the TRE that caused
* the event (which will be the last one used by the transaction).
@ -777,7 +782,7 @@ int gsi_channel_trans_init(struct gsi *gsi, u32 channel_id)
err_map_free:
kfree(trans_info->map);
err_trans_free:
gsi_trans_pool_exit(&trans_info->pool);
kfree(trans_info->trans);
dev_err(gsi->dev, "error %d initializing channel %u transactions\n",
ret, channel_id);
@ -791,6 +796,6 @@ void gsi_channel_trans_exit(struct gsi_channel *channel)
struct gsi_trans_info *trans_info = &channel->trans_info;
gsi_trans_pool_exit(&trans_info->sg_pool);
gsi_trans_pool_exit(&trans_info->pool);
kfree(trans_info->trans);
kfree(trans_info->map);
}