[RFC,v4,0/1] fpga: improve protection against low-level control module unloading

Message

Marco Pagani Jan. 5, 2024, 11:15 p.m. UTC

This RFC proposes a solution to keep protecting the fpga manager against
the unloading of the low-level control modules while addressing the
limitations of the current implementation. Currently, the code assumes
that the low-level module registers a driver for the parent device that
is later used to take the module's refcount. This proposal removes this
limitation by adding a module owner field to the fpga_manager struct
that can be set while registering the manager.

For more context, please refer to these threads:
https://lore.kernel.org/linux-fpga/ZS6hhlvjUcqyv8zL@yilunxu-OptiPlex-7050
https://lore.kernel.org/linux-fpga/ZT9qENE9fE3Z0KCW@yilunxu-OptiPlex-7050

v4:
- Use helper macros to set the owner module
v3:
- Improved locking
v2:
- Fixed protection against races during module removal

Marco Pagani (1):
  fpga: add an owner and use it to take the low-level module's refcount

 drivers/fpga/fpga-mgr.c       | 93 ++++++++++++++++++++++-------------
 include/linux/fpga/fpga-mgr.h | 80 +++++++++++++++++++++++++++---
 2 files changed, 134 insertions(+), 39 deletions(-)


base-commit: 610a9b8f49fbcf1100716370d3b5f6f884a2835a