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From: Marco Pagani <marpagan@redhat.com>
To: Moritz Fischer <mdf@kernel.org>,
	Wu Hao <hao.wu@intel.com>,
	Xu Yilun <yilun.xu@intel.com>,
	Tom Rix <trix@redhat.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Marco Pagani <marpagan@redhat.com>,
	linux-kernel@vger.kernel.org,
	linux-fpga@vger.kernel.org
Subject: [RFC PATCH v4 0/1] fpga: improve protection against low-level control module unloading
Date: Sat,  6 Jan 2024 00:15:25 +0100
Message-ID: <20240105231526.109247-1-marpagan@redhat.com>
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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
-- 
2.43.0