[ANNOUNCE] Make fs operations const

From: Matthew Wilcox (willy_at_debian.org)
Date: 10/31/03

  • Next message: Jesse Pollard: "Re: Things that Longhorn seems to be doing right"
    Date:	Fri, 31 Oct 2003 13:49:45 +0000
    To: linux-fsdevel@vger.kernel.org
    
    

    The 54k patch at http://ftp.linux.org.uk/pub/linux/willy/patches/fs-const.diff
    makes many file_operations, dentry_operations, address_space_operations,
    inode_operations, super_operations and dquot_operations const.

    This was inspired by intermezzo doing something naughty which the
    compiler didn't know to warn about. By making these pointers point to
    const structs, the compiler knows we shouldn't be doing that and will
    issue a warning.

    As a bonus for the embedded people, this enables us to move more of the
    kernel into ROMmable sections. I've only done this for ext2 and a few
    well-known *_operations in this patch, but it could be done to many
    more filesystems. It only saves a few hundred bytes per filesystem,
    but it all adds up.

    -- 
    "It's not Hollywood.  War is real, war is primarily not about defeat or
    victory, it is about death.  I've seen thousands and thousands of dead bodies.
    Do you think I want to have an academic debate on this subject?" -- Robert Fisk
    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at  http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at  http://www.tux.org/lkml/
    

  • Next message: Jesse Pollard: "Re: Things that Longhorn seems to be doing right"

    Relevant Pages

    • Re: [2.6 patch] drivers/net/smc-mca.c: cleanups
      ... The compiler does use the const modifier on a static object to optimise ... int bar; ... send the line "unsubscribe linux-kernel" in ...
      (Linux-Kernel)
    • Re: How to convert Infix notation to postfix notation
      ... and make all strings const save where the intent ... function whose contract is to change the string. ... the compiler "just" prevents the string ... try to do using the pointer you get. ...
      (comp.lang.c)
    • Re: Writing single bits to a file
      ... The 'const' keyword provides the same kind of benefit that prototypes ... enabling the compiler to warn you if it detects the fact that you ... I had not gone and more correctly fixed up the precedence heirarchy (unary ... I like to implement scripting languages for breakfast ...
      (comp.lang.c)
    • Re: const
      ... > const modifiers, ... willing to remove the const'ness with a cast, ... I don't know how good a cross-file compiler could be - it would have to be ... it's a guarantee by the programmer. ...
      (comp.programming)
    • Re: Index a #define string
      ... In this case, i wouldn't use an array myself but a const char * const, but ... should one make it of static storage? ... If they were on the stack, where do you think their values ... You mean that the compiler optimises it out. ...
      (comp.lang.cpp)