LU-9859 libcfs: move tcd locking across to tracefile.c

[fs/lustre-release.git] / libcfs / libcfs / tracefile.c

diff --git a/libcfs/libcfs/tracefile.c b/libcfs/libcfs/tracefile.c
index 7ab2371..ac126e8 100644 (file)
--- a/libcfs/libcfs/tracefile.c
+++ b/libcfs/libcfs/tracefile.c
@@ -63,6 +63,64 @@ static DECLARE_RWSEM(cfs_tracefile_sem);
 static void put_pages_on_tcd_daemon_list(struct page_collection *pc,
                                        struct cfs_trace_cpu_data *tcd);
 
+/* trace file lock routines */
+/* The walking argument indicates the locking comes from all tcd types
+ * iterator and we must lock it and dissable local irqs to avoid deadlocks
+ * with other interrupt locks that might be happening. See LU-1311
+ * for details.
+ */
+int cfs_trace_lock_tcd(struct cfs_trace_cpu_data *tcd, int walking)
+       __acquires(&tcd->tcd_lock)
+{
+       __LASSERT(tcd->tcd_type < CFS_TCD_TYPE_MAX);
+       if (tcd->tcd_type == CFS_TCD_TYPE_IRQ)
+               spin_lock_irqsave(&tcd->tcd_lock, tcd->tcd_lock_flags);
+       else if (tcd->tcd_type == CFS_TCD_TYPE_SOFTIRQ)
+               spin_lock_bh(&tcd->tcd_lock);
+       else if (unlikely(walking))
+               spin_lock_irq(&tcd->tcd_lock);
+       else
+               spin_lock(&tcd->tcd_lock);
+       return 1;
+}
+
+void cfs_trace_unlock_tcd(struct cfs_trace_cpu_data *tcd, int walking)
+       __releases(&tcd->tcd_lock)
+{
+       __LASSERT(tcd->tcd_type < CFS_TCD_TYPE_MAX);
+       if (tcd->tcd_type == CFS_TCD_TYPE_IRQ)
+               spin_unlock_irqrestore(&tcd->tcd_lock, tcd->tcd_lock_flags);
+       else if (tcd->tcd_type == CFS_TCD_TYPE_SOFTIRQ)
+               spin_unlock_bh(&tcd->tcd_lock);
+       else if (unlikely(walking))
+               spin_unlock_irq(&tcd->tcd_lock);
+       else
+               spin_unlock(&tcd->tcd_lock);
+}
+
+#define cfs_tcd_for_each_type_lock(tcd, i, cpu)                                \
+       for (i = 0; cfs_trace_data[i] &&                                \
+            (tcd = &(*cfs_trace_data[i])[cpu].tcd) &&                  \
+            cfs_trace_lock_tcd(tcd, 1); cfs_trace_unlock_tcd(tcd, 1), i++)
+
+static inline struct cfs_trace_cpu_data *
+cfs_trace_get_tcd(void)
+{
+       struct cfs_trace_cpu_data *tcd =
+               &(*cfs_trace_data[cfs_trace_buf_idx_get()])[get_cpu()].tcd;
+
+       cfs_trace_lock_tcd(tcd, 0);
+
+       return tcd;
+}
+
+static inline void cfs_trace_put_tcd(struct cfs_trace_cpu_data *tcd)
+{
+       cfs_trace_unlock_tcd(tcd, 0);
+
+       put_cpu();
+}
+
 static inline struct cfs_trace_page *
 cfs_tage_from_list(struct list_head *list)
 {