Where does user_path_walk() live?

[kevin conaway <kconaway_is@yahoo.com>]

I am a student doing an independent study on
filesystem security and I was trying to pin down
exactly where a users permissions are checked when
trying to access a particular file.  Looking through
the various system calls in /usr/src/linux/fs/open.c
tells me that each call that requires a permission
check calls user_path_walk() to essentially "walk"
through the parts of the path to make sure the sure
has access to each part.  I attempted to find the code
for user_path_walk() but all I could find was a
#define statement that showed user_path_walk was
really a macro for __user_walk().  All I could find
were symbol references for __user_walk() in the kernel
tree.  Does anyone know where this code lives?

Thanks

Kevin Conaway

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