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    Subject[PATCH 3.14 34/59] NFS: Use raw_write_seqcount_begin/end int nfs4_reclaim_open_state
    Date
    3.14-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Trond Myklebust <trond.myklebust@primarydata.com>

    commit abbec2da13f0e4c5d9b78b7e2c025a3e617228ba upstream.

    The addition of lockdep code to write_seqcount_begin/end has lead to
    a bunch of false positive claims of ABBA deadlocks with the so_lock
    spinlock. Audits show that this simply cannot happen because the
    read side code does not spin while holding so_lock.

    Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    fs/nfs/nfs4state.c | 6 +++---
    1 file changed, 3 insertions(+), 3 deletions(-)

    --- a/fs/nfs/nfs4state.c
    +++ b/fs/nfs/nfs4state.c
    @@ -1456,7 +1456,7 @@ static int nfs4_reclaim_open_state(struc
    * server that doesn't support a grace period.
    */
    spin_lock(&sp->so_lock);
    - write_seqcount_begin(&sp->so_reclaim_seqcount);
    + raw_write_seqcount_begin(&sp->so_reclaim_seqcount);
    restart:
    list_for_each_entry(state, &sp->so_states, open_states) {
    if (!test_and_clear_bit(ops->state_flag_bit, &state->flags))
    @@ -1519,13 +1519,13 @@ restart:
    spin_lock(&sp->so_lock);
    goto restart;
    }
    - write_seqcount_end(&sp->so_reclaim_seqcount);
    + raw_write_seqcount_end(&sp->so_reclaim_seqcount);
    spin_unlock(&sp->so_lock);
    return 0;
    out_err:
    nfs4_put_open_state(state);
    spin_lock(&sp->so_lock);
    - write_seqcount_end(&sp->so_reclaim_seqcount);
    + raw_write_seqcount_end(&sp->so_reclaim_seqcount);
    spin_unlock(&sp->so_lock);
    return status;
    }



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