net: remove packet pool.

The pool was prone to deadlocks, especially due to having a single pool
for rx+tx. If the pool got full with rx'd packets it would deadlock because
processing a rx packet requires doing another allocation on the pool, for
the possibly tx'd response, before deallocating the rx'd packet.

This also allows Device impls to allocate the packet memory in a particular
RAM kind, if needed for example to do DMA.

The `Device` trait is now token-based, like smoltcp's. In the end, this
is better because it allows callers to manage memory however they want (including
with a pool if they want to).

1 files changed, 1 insertions, 5 deletions

diff --git a/embassy-net/src/lib.rs b/embassy-net/src/lib.rs
index edb969842..e18e819cb 100644
--- a/embassy-net/src/lib.rs
+++ b/embassy-net/src/lib.rs
@@ -8,12 +8,9 @@
 // This mod MUST go first, so that the others see its macros.
 pub(crate) mod fmt;
 
-mod device;
-mod packet_pool;
+pub mod device;
 mod stack;
 
-pub use device::{Device, LinkState};
-pub use packet_pool::{Packet, PacketBox, PacketBoxExt, PacketBuf, MTU};
 pub use stack::{Config, ConfigStrategy, Stack, StackResources};
 
 #[cfg(feature = "tcp")]
@@ -23,7 +20,6 @@ pub mod tcp;
 pub mod udp;
 
 // smoltcp reexports
-pub use smoltcp::phy::{DeviceCapabilities, Medium};
 pub use smoltcp::time::{Duration as SmolDuration, Instant as SmolInstant};
 #[cfg(feature = "medium-ethernet")]
 pub use smoltcp::wire::{EthernetAddress, HardwareAddress};