Merge branch 'net-netpoll-improve-skb-pool-management'

Breno Leitao says:

====================
net: netpoll: Improve SKB pool management

The netpoll subsystem pre-allocates 32 SKBs in a pool for emergency use
during out-of-memory conditions. However, the current implementation has
several inefficiencies:

 * The SKB pool, once allocated, is never freed:
	 * Resources remain allocated even after netpoll users are removed
	 * Failed initialization can leave pool populated forever
 * The global pool design makes resource tracking difficult

This series addresses these issues through three patches:

Patch 1 ("net: netpoll: Individualize the skb pool"):
 - Replace global pool with per-user pools in netpoll struct

Patch 2 ("net: netpoll: flush skb pool during cleanup"):
- Properly free pool resources during netconsole cleanup

These changes improve resource management and make the code more
maintainable.  As a side benefit, the improved structure would allow
netpoll to be modularized if desired in the future.

v2: https://lore.kernel.org/20241107-skb_buffers_v2-v2-0-288c6264ba4f@debian.org
v1: https://lore.kernel.org/20241025142025.3558051-1-leitao@debian.org
====================

Link: https://patch.msgid.link/20241114-skb_buffers_v2-v3-0-9be9f52a8b69@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>