-extern int lprocfs_stats_alloc_one(struct lprocfs_stats *stats,
- unsigned int cpuid);
-
-/**
- * Lock statistics structure for access, possibly only on this CPU.
- *
- * The statistics struct may be allocated with per-CPU structures for
- * efficient concurrent update (usually only on server-wide stats), or
- * as a single global struct (e.g. for per-client or per-job statistics),
- * so the required locking depends on the type of structure allocated.
- *
- * For per-CPU statistics, pin the thread to the current cpuid so that
- * will only access the statistics for that CPU. If the stats structure
- * for the current CPU has not been allocated (or previously freed),
- * allocate it now. The per-CPU statistics do not need locking since
- * the thread is pinned to the CPU during update.
- *
- * For global statistics, lock the stats structure to prevent concurrent update.
- *
- * \param[in] stats statistics structure to lock
- * \param[in] opc type of operation:
- * LPROCFS_GET_SMP_ID: "lock" and return current CPU index
- * for incrementing statistics for that CPU
- * LPROCFS_GET_NUM_CPU: "lock" and return number of used
- * CPU indices to iterate over all indices
- * \param[out] flags CPU interrupt saved state for IRQ-safe locking
- *
- * \retval cpuid of current thread or number of allocated structs
- * \retval negative on error (only for opc LPROCFS_GET_SMP_ID + per-CPU stats)
- */
-static inline int lprocfs_stats_lock(struct lprocfs_stats *stats,
- enum lprocfs_stats_lock_ops opc,
- unsigned long *flags)
-{
- if (stats->ls_flags & LPROCFS_STATS_FLAG_NOPERCPU) {
- if (stats->ls_flags & LPROCFS_STATS_FLAG_IRQ_SAFE)
- spin_lock_irqsave(&stats->ls_lock, *flags);
- else
- spin_lock(&stats->ls_lock);
- return opc == LPROCFS_GET_NUM_CPU ? 1 : 0;
- }
-
- switch (opc) {
- case LPROCFS_GET_SMP_ID: {
- unsigned int cpuid = get_cpu();
-
- if (unlikely(stats->ls_percpu[cpuid] == NULL)) {
- int rc = lprocfs_stats_alloc_one(stats, cpuid);
- if (rc < 0) {
- put_cpu();
- return rc;
- }
- }
- return cpuid;
- }
- case LPROCFS_GET_NUM_CPU:
- return stats->ls_biggest_alloc_num;
- default:
- LBUG();
- }
-}
-
-/**
- * Unlock statistics structure after access.
- *
- * Unlock the lock acquired via lprocfs_stats_lock() for global statistics,
- * or unpin this thread from the current cpuid for per-CPU statistics.
- *
- * This function must be called using the same arguments as used when calling
- * lprocfs_stats_lock() so that the correct operation can be performed.
- *
- * \param[in] stats statistics structure to unlock
- * \param[in] opc type of operation (current cpuid or number of structs)
- * \param[in] flags CPU interrupt saved state for IRQ-safe locking
- */
-static inline void lprocfs_stats_unlock(struct lprocfs_stats *stats,
- enum lprocfs_stats_lock_ops opc,
- unsigned long *flags)
-{
- if (stats->ls_flags & LPROCFS_STATS_FLAG_NOPERCPU) {
- if (stats->ls_flags & LPROCFS_STATS_FLAG_IRQ_SAFE)
- spin_unlock_irqrestore(&stats->ls_lock, *flags);
- else
- spin_unlock(&stats->ls_lock);
- } else if (opc == LPROCFS_GET_SMP_ID) {
- put_cpu();
- }
-}