lkml.org 
[lkml]   [2009]   [Apr]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    Subject[tip:x86/pat] x86: Document get_user_pages_fast()
    Commit-ID:  a0d22f485af1553060b4094ee0154537a8f6a8a6
    Gitweb: http://git.kernel.org/tip/a0d22f485af1553060b4094ee0154537a8f6a8a6
    Author: Andy Grover <andy.grover@oracle.com>
    AuthorDate: Thu, 9 Apr 2009 16:45:29 -0700
    Committer: Ingo Molnar <mingo@elte.hu>
    CommitDate: Fri, 10 Apr 2009 13:14:08 +0200

    x86: Document get_user_pages_fast()

    While better than get_user_pages(), the usage of gupf(),
    especially the return values and the fact that it can
    potentially only partially pin the range, warranted some
    documentation.

    Signed-off-by: Andy Grover <andy.grover@oracle.com>
    Cc: npiggin@suse.de
    Cc: akpm@linux-foundation.org
    LKML-Reference: <1239320729-3262-1-git-send-email-andy.grover@oracle.com>
    Signed-off-by: Ingo Molnar <mingo@elte.hu>


    ---
    arch/x86/mm/gup.c | 16 ++++++++++++++++
    1 files changed, 16 insertions(+), 0 deletions(-)

    diff --git a/arch/x86/mm/gup.c b/arch/x86/mm/gup.c
    index be54176..6340cef 100644
    --- a/arch/x86/mm/gup.c
    +++ b/arch/x86/mm/gup.c
    @@ -219,6 +219,22 @@ static int gup_pud_range(pgd_t pgd, unsigned long addr, unsigned long end,
    return 1;
    }

    +/**
    + * get_user_pages_fast() - pin user pages in memory
    + * @start: starting user address
    + * @nr_pages: number of pages from start to pin
    + * @write: whether pages will be written to
    + * @pages: array that receives pointers to the pages pinned.
    + * Should be at least nr_pages long.
    + *
    + * Attempt to pin user pages in memory without taking mm->mmap_sem.
    + * If not successful, it will fall back to taking the lock and
    + * calling get_user_pages().
    + *
    + * Returns number of pages pinned. This may be fewer than the number
    + * requested. If nr_pages is 0 or negative, returns 0. If no pages
    + * were pinned, returns -errno.
    + */
    int get_user_pages_fast(unsigned long start, int nr_pages, int write,
    struct page **pages)
    {

    \
     
     \ /
      Last update: 2009-04-10 14:37    [W:0.023 / U:0.784 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site