1da11f8220
The current implementation of the fpga bridge assumes that the low-level
module registers a driver for the parent device and uses its owner pointer
to take the module's refcount. This approach is problematic since it can
lead to a null pointer dereference while attempting to get the bridge if
the parent device does not have a driver.
To address this problem, add a module owner pointer to the fpga_bridge
struct and use it to take the module's refcount. Modify the function for
registering a bridge to take an additional owner module parameter and
rename it to avoid conflicts. Use the old function name for a helper macro
that automatically sets the module that registers the bridge as the owner.
This ensures compatibility with existing low-level control modules and
reduces the chances of registering a bridge without setting the owner.
Also, update the documentation to keep it consistent with the new interface
for registering an fpga bridge.
Other changes: opportunistically move put_device() from __fpga_bridge_get()
to fpga_bridge_get() and of_fpga_bridge_get() to improve code clarity since
the bridge device is taken in these functions.
Fixes: 21aeda950c ("fpga: add fpga bridge framework")
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Suggested-by: Xu Yilun <yilun.xu@intel.com>
Reviewed-by: Russ Weight <russ.weight@linux.dev>
Signed-off-by: Marco Pagani <marpagan@redhat.com>
Acked-by: Xu Yilun <yilun.xu@intel.com>
Link: https://lore.kernel.org/r/20240322171839.233864-1-marpagan@redhat.com
Signed-off-by: Xu Yilun <yilun.xu@linux.intel.com>
26 lines
749 B
ReStructuredText
26 lines
749 B
ReStructuredText
FPGA Bridge
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===========
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API to implement a new FPGA bridge
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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* struct fpga_bridge - The FPGA Bridge structure
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* struct fpga_bridge_ops - Low level Bridge driver ops
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* __fpga_bridge_register() - Create and register a bridge
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* fpga_bridge_unregister() - Unregister a bridge
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The helper macro ``fpga_bridge_register()`` automatically sets
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the module that registers the FPGA bridge as the owner.
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.. kernel-doc:: include/linux/fpga/fpga-bridge.h
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:functions: fpga_bridge
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.. kernel-doc:: include/linux/fpga/fpga-bridge.h
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:functions: fpga_bridge_ops
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.. kernel-doc:: drivers/fpga/fpga-bridge.c
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:functions: __fpga_bridge_register
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.. kernel-doc:: drivers/fpga/fpga-bridge.c
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:functions: fpga_bridge_unregister
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