1. 11 8月, 2010 11 次提交
  2. 10 8月, 2010 1 次提交
    • C
      kmap_atomic: make kunmap_atomic() harder to misuse · 597781f3
      Cesar Eduardo Barros 提交于
      kunmap_atomic() is currently at level -4 on Rusty's "Hard To Misuse"
      list[1] ("Follow common convention and you'll get it wrong"), except in
      some architectures when CONFIG_DEBUG_HIGHMEM is set[2][3].
      
      kunmap() takes a pointer to a struct page; kunmap_atomic(), however, takes
      takes a pointer to within the page itself.  This seems to once in a while
      trip people up (the convention they are following is the one from
      kunmap()).
      
      Make it much harder to misuse, by moving it to level 9 on Rusty's list[4]
      ("The compiler/linker won't let you get it wrong").  This is done by
      refusing to build if the type of its first argument is a pointer to a
      struct page.
      
      The real kunmap_atomic() is renamed to kunmap_atomic_notypecheck()
      (which is what you would call in case for some strange reason calling it
      with a pointer to a struct page is not incorrect in your code).
      
      The previous version of this patch was compile tested on x86-64.
      
      [1] http://ozlabs.org/~rusty/index.cgi/tech/2008-04-01.html
      [2] In these cases, it is at level 5, "Do it right or it will always
          break at runtime."
      [3] At least mips and powerpc look very similar, and sparc also seems to
          share a common ancestor with both; there seems to be quite some
          degree of copy-and-paste coding here. The include/asm/highmem.h file
          for these three archs mention x86 CPUs at its top.
      [4] http://ozlabs.org/~rusty/index.cgi/tech/2008-03-30.html
      [5] As an aside, could someone tell me why mn10300 uses unsigned long as
          the first parameter of kunmap_atomic() instead of void *?
      Signed-off-by: NCesar Eduardo Barros <cesarb@cesarb.net>
      Cc: Russell King <linux@arm.linux.org.uk> (arch/arm)
      Cc: Ralf Baechle <ralf@linux-mips.org> (arch/mips)
      Cc: David Howells <dhowells@redhat.com> (arch/frv, arch/mn10300)
      Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com> (arch/mn10300)
      Cc: Kyle McMartin <kyle@mcmartin.ca> (arch/parisc)
      Cc: Helge Deller <deller@gmx.de> (arch/parisc)
      Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> (arch/parisc)
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> (arch/powerpc)
      Cc: Paul Mackerras <paulus@samba.org> (arch/powerpc)
      Cc: "David S. Miller" <davem@davemloft.net> (arch/sparc)
      Cc: Thomas Gleixner <tglx@linutronix.de> (arch/x86)
      Cc: Ingo Molnar <mingo@redhat.com> (arch/x86)
      Cc: "H. Peter Anvin" <hpa@zytor.com> (arch/x86)
      Cc: Arnd Bergmann <arnd@arndb.de> (include/asm-generic)
      Cc: Rusty Russell <rusty@rustcorp.com.au> ("Hard To Misuse" list)
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      597781f3
  3. 06 8月, 2010 14 次提交
  4. 05 8月, 2010 4 次提交
  5. 04 8月, 2010 10 次提交