patch-2.3.12 linux/fs/iobuf.c

• Lines: 137
• Date: Mon Jul 26 22:50:35 1999
• Orig file: v2.3.11/linux/fs/iobuf.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.3.11/linux/fs/iobuf.c linux/fs/iobuf.c
@@ -0,0 +1,136 @@
+/*
+ * iobuf.c
+ *
+ * Keep track of the general-purpose IO-buffer structures used to track
+ * abstract kernel-space io buffers.
+ * 
+ */
+
+#include <linux/iobuf.h>
+#include <linux/malloc.h>
+#include <linux/slab.h>
+
+static kmem_cache_t *kiobuf_cachep;
+
+/*
+ * The default IO completion routine for kiobufs: just wake up
+ * the kiobuf, nothing more.  
+ */
+
+void simple_wakeup_kiobuf(struct kiobuf *kiobuf)
+{
+	wake_up(&kiobuf->wait_queue);
+}
+
+
+void __init kiobuf_init(void)
+{
+	kiobuf_cachep =  kmem_cache_create("kiobuf",
+					   sizeof(struct kiobuf),
+					   0,
+					   SLAB_HWCACHE_ALIGN, NULL, NULL);
+	if(!kiobuf_cachep)
+		panic("Cannot create kernel iobuf cache\n");
+}
+
+
+int alloc_kiovec(int nr, struct kiobuf **bufp)
+{
+	int i;
+	struct kiobuf *iobuf;
+	
+	for (i = 0; i < nr; i++) {
+		iobuf = kmem_cache_alloc(kiobuf_cachep, SLAB_KERNEL);
+		if (!iobuf) {
+			free_kiovec(i, bufp);
+			return -ENOMEM;
+		}
+		
+		memset(iobuf, 0, sizeof(*iobuf));
+		init_waitqueue_head(&iobuf->wait_queue);
+		iobuf->end_io = simple_wakeup_kiobuf;
+		iobuf->array_len = KIO_STATIC_PAGES;
+		iobuf->pagelist  = iobuf->page_array;
+		iobuf->maplist   = iobuf->map_array;
+		*bufp++ = iobuf;
+	}
+	
+	return 0;
+}
+
+void free_kiovec(int nr, struct kiobuf **bufp) 
+{
+	int i;
+	struct kiobuf *iobuf;
+	
+	for (i = 0; i < nr; i++) {
+		iobuf = bufp[i];
+		if (iobuf->array_len > KIO_STATIC_PAGES) {
+			kfree (iobuf->pagelist);
+			kfree (iobuf->maplist);
+		}
+		kmem_cache_free(kiobuf_cachep, bufp[i]);
+	}
+}
+
+int expand_kiobuf(struct kiobuf *iobuf, int wanted)
+{
+	unsigned long *	pagelist;
+	struct page ** maplist;
+	
+	if (iobuf->array_len >= wanted)
+		return 0;
+	
+	pagelist = (unsigned long *) 
+		kmalloc(wanted * sizeof(unsigned long), GFP_KERNEL);
+	if (!pagelist)
+		return -ENOMEM;
+	
+	maplist = (struct page **) 
+		kmalloc(wanted * sizeof(struct page **), GFP_KERNEL);
+	if (!maplist) {
+		kfree(pagelist);
+		return -ENOMEM;
+	}
+
+	/* Did it grow while we waited? */
+	if (iobuf->array_len >= wanted) {
+		kfree(pagelist);
+		kfree(maplist);
+		return 0;
+	}
+	
+	memcpy (pagelist, iobuf->pagelist, wanted * sizeof(unsigned long));
+	memcpy (maplist,  iobuf->maplist,   wanted * sizeof(struct page **));
+
+	if (iobuf->array_len > KIO_STATIC_PAGES) {
+		kfree (iobuf->pagelist);
+		kfree (iobuf->maplist);
+	}
+	
+	iobuf->pagelist  = pagelist;
+	iobuf->maplist   = maplist;
+	iobuf->array_len = wanted;
+	return 0;
+}
+
+
+void kiobuf_wait_for_io(struct kiobuf *kiobuf)
+{
+	struct task_struct *tsk = current;
+	DECLARE_WAITQUEUE(wait, tsk);
+
+	add_wait_queue(&kiobuf->wait_queue, &wait);
+repeat:
+	tsk->state = TASK_UNINTERRUPTIBLE;
+	run_task_queue(&tq_disk);
+	if (atomic_read(&kiobuf->io_count) != 0) {
+		schedule();
+		goto repeat;
+	}
+	tsk->state = TASK_RUNNING;
+	remove_wait_queue(&kiobuf->wait_queue, &wait);
+}
+
+
+