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    Subject[PATCH v2 2/2] m2p_find_override: use list_for_each_entry_safe
    Date
    Use list_for_each_entry_safe and remove the spin_lock acquisition in
    m2p_find_override: getting stale entries is OK because we should never
    get an m2p_find_override call looking for an entry that we are about to
    add or delete.

    Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
    ---
    arch/x86/xen/p2m.c | 9 ++-------
    1 files changed, 2 insertions(+), 7 deletions(-)

    diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
    index 1b267e7..a4d35d4 100644
    --- a/arch/x86/xen/p2m.c
    +++ b/arch/x86/xen/p2m.c
    @@ -807,23 +807,18 @@ EXPORT_SYMBOL_GPL(m2p_remove_override);

    struct page *m2p_find_override(unsigned long mfn)
    {
    - unsigned long flags;
    struct list_head *bucket = &m2p_overrides[mfn_hash(mfn)];
    - struct page *p, *ret;
    + struct page *p, *t, *ret;

    ret = NULL;

    - spin_lock_irqsave(&m2p_override_lock, flags);
    -
    - list_for_each_entry(p, bucket, lru) {
    + list_for_each_entry_safe(p, t, bucket, lru) {
    if (page_private(p) == mfn) {
    ret = p;
    break;
    }
    }

    - spin_unlock_irqrestore(&m2p_override_lock, flags);
    -
    return ret;
    }

    --
    1.7.2.5


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