+++ /dev/null
-/* charqueue.c
- *
- * Copyright (C) 2010 - 2013 UNISYS CORPORATION
- * All rights reserved.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or (at
- * your option) any later version.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
- * NON INFRINGEMENT. See the GNU General Public License for more
- * details.
- */
-
-/*
- * Simple character queue implementation for Linux kernel mode.
- */
-
-#include "charqueue.h"
-
-#define MYDRVNAME "charqueue"
-
-#define IS_EMPTY(charqueue) (charqueue->head == charqueue->tail)
-
-struct charqueue {
- int alloc_size;
- int nslots;
- spinlock_t lock; /* read/write lock for this structure */
- int head, tail;
- unsigned char buf[0];
-};
-
-struct charqueue *visor_charqueue_create(ulong nslots)
-{
- int alloc_size = sizeof(struct charqueue) + nslots + 1;
- struct charqueue *cq;
-
- cq = kmalloc(alloc_size, GFP_KERNEL|__GFP_NORETRY);
- if (cq == NULL)
- return NULL;
- cq->alloc_size = alloc_size;
- cq->nslots = nslots;
- cq->head = 0;
- cq->tail = 0;
- spin_lock_init(&cq->lock);
- return cq;
-}
-EXPORT_SYMBOL_GPL(visor_charqueue_create);
-
-void visor_charqueue_enqueue(struct charqueue *charqueue, unsigned char c)
-{
- int alloc_slots = charqueue->nslots+1; /* 1 slot is always empty */
-
- spin_lock(&charqueue->lock);
- charqueue->head = (charqueue->head+1) % alloc_slots;
- if (charqueue->head == charqueue->tail)
- /* overflow; overwrite the oldest entry */
- charqueue->tail = (charqueue->tail+1) % alloc_slots;
- charqueue->buf[charqueue->head] = c;
- spin_unlock(&charqueue->lock);
-}
-EXPORT_SYMBOL_GPL(visor_charqueue_enqueue);
-
-bool visor_charqueue_is_empty(struct charqueue *charqueue)
-{
- bool b;
-
- spin_lock(&charqueue->lock);
- b = IS_EMPTY(charqueue);
- spin_unlock(&charqueue->lock);
- return b;
-}
-EXPORT_SYMBOL_GPL(visor_charqueue_is_empty);
-
-static int charqueue_dequeue_1(struct charqueue *charqueue)
-{
- int alloc_slots = charqueue->nslots + 1; /* 1 slot is always empty */
-
- if (IS_EMPTY(charqueue))
- return -1;
- charqueue->tail = (charqueue->tail+1) % alloc_slots;
- return charqueue->buf[charqueue->tail];
-}
-
-int charqueue_dequeue(struct charqueue *charqueue)
-{
- int rc;
-
- spin_lock(&charqueue->lock);
- rc = charqueue_dequeue_1(charqueue);
- spin_unlock(&charqueue->lock);
- return rc;
-}
-
-int visor_charqueue_dequeue_n(struct charqueue *charqueue, unsigned char *buf,
- int n)
-{
- int rc, counter = 0, c;
-
- spin_lock(&charqueue->lock);
- for (;;) {
- if (n <= 0)
- break; /* no more buffer space */
- c = charqueue_dequeue_1(charqueue);
- if (c < 0)
- break; /* no more input */
- *buf = (unsigned char)(c);
- buf++;
- n--;
- counter++;
- }
- rc = counter;
- spin_unlock(&charqueue->lock);
- return rc;
-}
-EXPORT_SYMBOL_GPL(visor_charqueue_dequeue_n);
-
-void visor_charqueue_destroy(struct charqueue *charqueue)
-{
- if (charqueue == NULL)
- return;
- kfree(charqueue);
-}
-EXPORT_SYMBOL_GPL(visor_charqueue_destroy);
+++ /dev/null
-/* charqueue.h
- *
- * Copyright (C) 2010 - 2013 UNISYS CORPORATION
- * All rights reserved.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or (at
- * your option) any later version.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
- * NON INFRINGEMENT. See the GNU General Public License for more
- * details.
- */
-
-#ifndef __CHARQUEUE_H__
-#define __CHARQUEUE_H__
-
-#include "timskmod.h"
-
-/* struct charqueue is an opaque structure to users.
- * Fields are declared only in the implementation .c files.
- */
-struct charqueue;
-
-struct charqueue *visor_charqueue_create(ulong nslots);
-void visor_charqueue_enqueue(struct charqueue *charqueue, unsigned char c);
-int charqueue_dequeue(struct charqueue *charqueue);
-int visor_charqueue_dequeue_n(struct charqueue *charqueue, unsigned char *buf,
- int n);
-bool visor_charqueue_is_empty(struct charqueue *charqueue);
-void visor_charqueue_destroy(struct charqueue *charqueue);
-
-#endif
-