• Kirill A. Shutemov's avatar
    mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros · 09cbfeaf
    Kirill A. Shutemov authored
    PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time
    ago with promise that one day it will be possible to implement page
    cache with bigger chunks than PAGE_SIZE.
    
    This promise never materialized.  And unlikely will.
    
    We have many places where PAGE_CACHE_SIZE assumed to be equal to
    PAGE_SIZE.  And it's constant source of confusion on whether
    PAGE_CACHE_* or PAGE_* constant should be used in a particular case,
    especially on the border between fs and mm.
    
    Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much
    breakage to be doable.
    
    Let's stop pretending that pages in page cache are special.  They are
    not.
    
    The changes are pretty straight-forward:
    
     - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;
    
     - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;
    
     - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN};
    
     - page_cache_get() -> get_page();
    
     - page_cache_release() -> put_page();
    
    This patch contains automated changes generated with coccinelle using
    script below.  For some reason, coccinelle doesn't patch header files.
    I've called spatch for them manually.
    
    The only adjustment after coccinelle is revert of changes to
    PAGE_CAHCE_ALIGN definition: we are going to drop it later.
    
    There are few places in the code where coccinelle didn't reach.  I'll
    fix them manually in a separate patch.  Comments and documentation also
    will be addressed with the separate patch.
    
    virtual patch
    
    @@
    expression E;
    @@
    - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT)
    + E
    
    @@
    expression E;
    @@
    - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT)
    + E
    
    @@
    @@
    - PAGE_CACHE_SHIFT
    + PAGE_SHIFT
    
    @@
    @@
    - PAGE_CACHE_SIZE
    + PAGE_SIZE
    
    @@
    @@
    - PAGE_CACHE_MASK
    + PAGE_MASK
    
    @@
    expression E;
    @@
    - PAGE_CACHE_ALIGN(E)
    + PAGE_ALIGN(E)
    
    @@
    expression E;
    @@
    - page_cache_get(E)
    + get_page(E)
    
    @@
    expression E;
    @@
    - page_cache_release(E)
    + put_page(E)
    Signed-off-by: 's avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
    Acked-by: 's avatarMichal Hocko <mhocko@suse.com>
    Signed-off-by: 's avatarLinus Torvalds <torvalds@linux-foundation.org>
    09cbfeaf
tail_conversion.c 9.14 KB