Implement a few updates to Jakub's RFC memory provider API to make it
suitable for device memory TCP:
1. Currently for devmem TCP the driver's netdev_rx_queue holds a reference to
the dma_buf_pages struct and needs to pass that to the page_pool's memory
provider somehow. For PoC purposes, create a pp->mp_priv field that is set
by the driver. Likely needs a better API (likely dependant on the
general memory provider API).
2. The current memory_provider API gives the memory_provider the option
to override put_page(), but tries page_pool_clear_pp_info() after the
memory provider has released the page. IMO if the page freeing is
delegated to the provider then the page_pool should not modify the
page after release_page() has been called.
Signed-off-by: Mina Almasry <almasrymina@xxxxxxxxxx>
---
include/net/page_pool.h | 1 +
net/core/page_pool.c | 7 ++++---
2 files changed, 5 insertions(+), 3 deletions(-)
diff --git a/include/net/page_pool.h b/include/net/page_pool.h
index 364fe6924258..7b6668479baf 100644
--- a/include/net/page_pool.h
+++ b/include/net/page_pool.h
@@ -78,6 +78,7 @@ struct page_pool_params {
struct device *dev; /* device, for DMA pre-mapping purposes */
struct napi_struct *napi; /* Sole consumer of pages, otherwise NULL */
u8 memory_provider; /* haaacks! should be user-facing */
+ void *mp_priv; /* argument to pass to the memory provider */
enum dma_data_direction dma_dir; /* DMA mapping direction */
unsigned int max_len; /* max DMA sync memory size */
unsigned int offset; /* DMA addr offset */
diff --git a/net/core/page_pool.c b/net/core/page_pool.c
index d50f6728e4f6..df3f431fcff3 100644
--- a/net/core/page_pool.c
+++ b/net/core/page_pool.c
@@ -241,6 +241,7 @@ static int page_pool_init(struct page_pool *pool,
goto free_ptr_ring;
}
+ pool->mp_priv = pool->p.mp_priv;
if (pool->mp_ops) {
err = pool->mp_ops->init(pool);
if (err) {
@@ -564,16 +565,16 @@ void page_pool_return_page(struct page_pool *pool, struct page *page)
else
__page_pool_release_page_dma(pool, page);
- page_pool_clear_pp_info(page);
-
/* This may be the last page returned, releasing the pool, so
* it is not safe to reference pool afterwards.
*/
count = atomic_inc_return_relaxed(&pool->pages_state_release_cnt);
trace_page_pool_state_release(pool, page, count);
- if (put)
+ if (put) {
+ page_pool_clear_pp_info(page);
put_page(page);
+ }
/* An optimization would be to call __free_pages(page, pool->p.order)
* knowing page is not part of page-cache (thus avoiding a
* __page_cache_release() call).
--
2.41.0.390.g38632f3daf-goog
