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    Subject[PATCH tip/core/rcu 14/20] rcu: Use wrapper for lockdep asserts
    Date
    From: Matthew Wilcox <mawilcox@microsoft.com>

    Commits c0b334c5bfa9 and ea9b0c8a26a2 introduced new sparse warnings
    by accessing rcu_node->lock directly and ignoring the __private
    marker. Introduce a new wrapper and use it. Also fix a similar problem
    in srcutree.c introduced by a3883df3935e.

    Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
    Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
    ---
    kernel/rcu/rcu.h | 5 ++++-
    kernel/rcu/srcutree.c | 2 +-
    kernel/rcu/tree.c | 24 ++++++++++++------------
    kernel/rcu/tree_plugin.h | 4 ++--
    4 files changed, 19 insertions(+), 16 deletions(-)

    diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
    index c90812673d54..5d13f651cf08 100644
    --- a/kernel/rcu/rcu.h
    +++ b/kernel/rcu/rcu.h
    @@ -337,7 +337,7 @@ do { \
    } while (0)

    #define raw_spin_unlock_irqrestore_rcu_node(p, flags) \
    - raw_spin_unlock_irqrestore(&ACCESS_PRIVATE(p, lock), flags) \
    + raw_spin_unlock_irqrestore(&ACCESS_PRIVATE(p, lock), flags)

    #define raw_spin_trylock_rcu_node(p) \
    ({ \
    @@ -348,6 +348,9 @@ do { \
    ___locked; \
    })

    +#define raw_lockdep_assert_held_rcu_node(p) \
    + lockdep_assert_held(&ACCESS_PRIVATE(p, lock))
    +
    #endif /* #if defined(SRCU) || !defined(TINY_RCU) */

    #ifdef CONFIG_TINY_RCU
    diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
    index d5cea81378cc..9c6e0eaab4d5 100644
    --- a/kernel/rcu/srcutree.c
    +++ b/kernel/rcu/srcutree.c
    @@ -439,7 +439,7 @@ static void srcu_gp_start(struct srcu_struct *sp)
    struct srcu_data *sdp = this_cpu_ptr(sp->sda);
    int state;

    - lockdep_assert_held(&sp->lock);
    + lockdep_assert_held(&ACCESS_PRIVATE(sp, lock));
    WARN_ON_ONCE(ULONG_CMP_GE(sp->srcu_gp_seq, sp->srcu_gp_seq_needed));
    rcu_segcblist_advance(&sdp->srcu_cblist,
    rcu_seq_current(&sp->srcu_gp_seq));
    diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
    index 4d7c727020f0..99d404c6bbbb 100644
    --- a/kernel/rcu/tree.c
    +++ b/kernel/rcu/tree.c
    @@ -1161,7 +1161,7 @@ static int rcu_is_cpu_rrupt_from_idle(void)
    */
    static void rcu_gpnum_ovf(struct rcu_node *rnp, struct rcu_data *rdp)
    {
    - lockdep_assert_held(&rnp->lock);
    + raw_lockdep_assert_held_rcu_node(rnp);
    if (ULONG_CMP_LT(READ_ONCE(rdp->gpnum) + ULONG_MAX / 4, rnp->gpnum))
    WRITE_ONCE(rdp->gpwrap, true);
    if (ULONG_CMP_LT(rdp->rcu_iw_gpnum + ULONG_MAX / 4, rnp->gpnum))
    @@ -1629,7 +1629,7 @@ void rcu_cpu_stall_reset(void)
    static unsigned long rcu_cbs_completed(struct rcu_state *rsp,
    struct rcu_node *rnp)
    {
    - lockdep_assert_held(&rnp->lock);
    + raw_lockdep_assert_held_rcu_node(rnp);

    /*
    * If RCU is idle, we just wait for the next grace period.
    @@ -1676,7 +1676,7 @@ rcu_start_future_gp(struct rcu_node *rnp, struct rcu_data *rdp,
    bool ret = false;
    struct rcu_node *rnp_root = rcu_get_root(rdp->rsp);

    - lockdep_assert_held(&rnp->lock);
    + raw_lockdep_assert_held_rcu_node(rnp);

    /*
    * Pick up grace-period number for new callbacks. If this
    @@ -1804,7 +1804,7 @@ static bool rcu_accelerate_cbs(struct rcu_state *rsp, struct rcu_node *rnp,
    {
    bool ret = false;

    - lockdep_assert_held(&rnp->lock);
    + raw_lockdep_assert_held_rcu_node(rnp);

    /* If no pending (not yet ready to invoke) callbacks, nothing to do. */
    if (!rcu_segcblist_pend_cbs(&rdp->cblist))
    @@ -1844,7 +1844,7 @@ static bool rcu_accelerate_cbs(struct rcu_state *rsp, struct rcu_node *rnp,
    static bool rcu_advance_cbs(struct rcu_state *rsp, struct rcu_node *rnp,
    struct rcu_data *rdp)
    {
    - lockdep_assert_held(&rnp->lock);
    + raw_lockdep_assert_held_rcu_node(rnp);

    /* If no pending (not yet ready to invoke) callbacks, nothing to do. */
    if (!rcu_segcblist_pend_cbs(&rdp->cblist))
    @@ -1872,7 +1872,7 @@ static bool __note_gp_changes(struct rcu_state *rsp, struct rcu_node *rnp,
    bool ret;
    bool need_gp;

    - lockdep_assert_held(&rnp->lock);
    + raw_lockdep_assert_held_rcu_node(rnp);

    /* Handle the ends of any preceding grace periods first. */
    if (rdp->completed == rnp->completed &&
    @@ -2297,7 +2297,7 @@ static bool
    rcu_start_gp_advanced(struct rcu_state *rsp, struct rcu_node *rnp,
    struct rcu_data *rdp)
    {
    - lockdep_assert_held(&rnp->lock);
    + raw_lockdep_assert_held_rcu_node(rnp);
    if (!rsp->gp_kthread || !cpu_needs_another_gp(rsp, rdp)) {
    /*
    * Either we have not yet spawned the grace-period
    @@ -2359,7 +2359,7 @@ static bool rcu_start_gp(struct rcu_state *rsp)
    static void rcu_report_qs_rsp(struct rcu_state *rsp, unsigned long flags)
    __releases(rcu_get_root(rsp)->lock)
    {
    - lockdep_assert_held(&rcu_get_root(rsp)->lock);
    + raw_lockdep_assert_held_rcu_node(rcu_get_root(rsp));
    WARN_ON_ONCE(!rcu_gp_in_progress(rsp));
    WRITE_ONCE(rsp->gp_flags, READ_ONCE(rsp->gp_flags) | RCU_GP_FLAG_FQS);
    raw_spin_unlock_irqrestore_rcu_node(rcu_get_root(rsp), flags);
    @@ -2384,7 +2384,7 @@ rcu_report_qs_rnp(unsigned long mask, struct rcu_state *rsp,
    unsigned long oldmask = 0;
    struct rcu_node *rnp_c;

    - lockdep_assert_held(&rnp->lock);
    + raw_lockdep_assert_held_rcu_node(rnp);

    /* Walk up the rcu_node hierarchy. */
    for (;;) {
    @@ -2448,7 +2448,7 @@ static void rcu_report_unblock_qs_rnp(struct rcu_state *rsp,
    unsigned long mask;
    struct rcu_node *rnp_p;

    - lockdep_assert_held(&rnp->lock);
    + raw_lockdep_assert_held_rcu_node(rnp);
    if (rcu_state_p == &rcu_sched_state || rsp != rcu_state_p ||
    rnp->qsmask != 0 || rcu_preempt_blocked_readers_cgp(rnp)) {
    raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
    @@ -2593,7 +2593,7 @@ static void rcu_cleanup_dead_rnp(struct rcu_node *rnp_leaf)
    long mask;
    struct rcu_node *rnp = rnp_leaf;

    - lockdep_assert_held(&rnp->lock);
    + raw_lockdep_assert_held_rcu_node(rnp);
    if (!IS_ENABLED(CONFIG_HOTPLUG_CPU) ||
    rnp->qsmaskinit || rcu_preempt_has_tasks(rnp))
    return;
    @@ -3596,7 +3596,7 @@ static void rcu_init_new_rnp(struct rcu_node *rnp_leaf)
    long mask;
    struct rcu_node *rnp = rnp_leaf;

    - lockdep_assert_held(&rnp->lock);
    + raw_lockdep_assert_held_rcu_node(rnp);
    for (;;) {
    mask = rnp->grpmask;
    rnp = rnp->parent;
    diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
    index 1c2d58a85511..84fbee4686d3 100644
    --- a/kernel/rcu/tree_plugin.h
    +++ b/kernel/rcu/tree_plugin.h
    @@ -180,7 +180,7 @@ static void rcu_preempt_ctxt_queue(struct rcu_node *rnp, struct rcu_data *rdp)
    (rnp->expmask & rdp->grpmask ? RCU_EXP_BLKD : 0);
    struct task_struct *t = current;

    - lockdep_assert_held(&rnp->lock);
    + raw_lockdep_assert_held_rcu_node(rnp);
    WARN_ON_ONCE(rdp->mynode != rnp);
    WARN_ON_ONCE(rnp->level != rcu_num_lvls - 1);

    @@ -1044,7 +1044,7 @@ static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags)
    {
    struct task_struct *t;

    - lockdep_assert_held(&rnp->lock);
    + raw_lockdep_assert_held_rcu_node(rnp);
    if (!rcu_preempt_blocked_readers_cgp(rnp) && rnp->exp_tasks == NULL) {
    raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
    return;
    --
    2.5.2
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