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7eab14de73
container_of() macro hides a local variable '__mptr' inside. This
becomes a problem when several container_of() are nested in each
other within single line or plain macros.
As C preprocessor doesn't support generating random variable names,
the sole solution is to avoid defining macros that consist only of
container_of() calls, or they will self-shadow '__mptr' each time:
In file included from ./include/linux/bitmap.h:10,
from drivers/net/phy/phy_device.c:12:
drivers/net/phy/phy_device.c: In function ‘phy_device_release’:
./include/linux/kernel.h:693:8: warning: declaration of ‘__mptr’ shadows a previous local [-Wshadow]
693 | void *__mptr = (void *)(ptr); \
| ^~~~~~
./include/linux/phy.h:647:26: note: in expansion of macro ‘container_of’
647 | #define to_phy_device(d) container_of(to_mdio_device(d), \
| ^~~~~~~~~~~~
./include/linux/mdio.h:52:27: note: in expansion of macro ‘container_of’
52 | #define to_mdio_device(d) container_of(d, struct mdio_device, dev)
| ^~~~~~~~~~~~
./include/linux/phy.h:647:39: note: in expansion of macro ‘to_mdio_device’
647 | #define to_phy_device(d) container_of(to_mdio_device(d), \
| ^~~~~~~~~~~~~~
drivers/net/phy/phy_device.c:217:8: note: in expansion of macro ‘to_phy_device’
217 | kfree(to_phy_device(dev));
| ^~~~~~~~~~~~~
./include/linux/kernel.h:693:8: note: shadowed declaration is here
693 | void *__mptr = (void *)(ptr); \
| ^~~~~~
./include/linux/phy.h:647:26: note: in expansion of macro ‘container_of’
647 | #define to_phy_device(d) container_of(to_mdio_device(d), \
| ^~~~~~~~~~~~
drivers/net/phy/phy_device.c:217:8: note: in expansion of macro ‘to_phy_device’
217 | kfree(to_phy_device(dev));
| ^~~~~~~~~~~~~
As they are declared in header files, these warnings are highly
repetitive and very annoying (along with the one from linux/pci.h).
Convert the related macros from linux/{mdio,phy}.h to static inlines
to avoid self-shadowing and potentially improve bug-catching.
No functional changes implied.
Signed-off-by: Alexander Lobakin <alobakin@pm.me>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20210116161246.67075-1-alobakin@pm.me
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.