Viewing file:  iobuf.c (2.82 KB) -rw-r--r--
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/*
* 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/slab.h>
#include <linux/vmalloc.h>
void end_kio_request(struct kiobuf *kiobuf, int uptodate)
{
if ((!uptodate) && !kiobuf->errno)
kiobuf->errno = -EIO;
if (atomic_dec_and_test(&kiobuf->io_count)) {
if (kiobuf->end_io)
kiobuf->end_io(kiobuf);
wake_up(&kiobuf->wait_queue);
}
}
static void kiobuf_init(struct kiobuf *iobuf)
{
memset(iobuf, 0, sizeof(*iobuf));
init_waitqueue_head(&iobuf->wait_queue);
iobuf->array_len = KIO_STATIC_PAGES;
iobuf->maplist = iobuf->map_array;
}
int alloc_kiobuf_bhs(struct kiobuf * kiobuf)
{
int i;
for (i = 0; i < KIO_MAX_SECTORS; i++)
if (!(kiobuf->bh[i] = kmem_cache_alloc(bh_cachep, SLAB_KERNEL))) {
while (i--) {
kmem_cache_free(bh_cachep, kiobuf->bh[i]);
kiobuf->bh[i] = NULL;
}
return -ENOMEM;
}
return 0;
}
void free_kiobuf_bhs(struct kiobuf * kiobuf)
{
int i;
for (i = 0; i < KIO_MAX_SECTORS; i++) {
kmem_cache_free(bh_cachep, kiobuf->bh[i]);
kiobuf->bh[i] = NULL;
}
}
int alloc_kiovec(int nr, struct kiobuf **bufp)
{
int i;
struct kiobuf *iobuf;
for (i = 0; i < nr; i++) {
iobuf = vmalloc(sizeof(struct kiobuf));
if (!iobuf) {
free_kiovec(i, bufp);
return -ENOMEM;
}
kiobuf_init(iobuf);
if (alloc_kiobuf_bhs(iobuf)) {
vfree(iobuf);
free_kiovec(i, bufp);
return -ENOMEM;
}
bufp[i] = 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->locked)
unlock_kiovec(1, &iobuf);
if (iobuf->array_len > KIO_STATIC_PAGES)
kfree (iobuf->maplist);
free_kiobuf_bhs(iobuf);
vfree(bufp[i]);
}
}
int expand_kiobuf(struct kiobuf *iobuf, int wanted)
{
struct page ** maplist;
if (iobuf->array_len >= wanted)
return 0;
maplist = (struct page **)
kmalloc(wanted * sizeof(struct page **), GFP_KERNEL);
if (!maplist)
return -ENOMEM;
/* Did it grow while we waited? */
if (iobuf->array_len >= wanted) {
kfree(maplist);
return 0;
}
memcpy (maplist, iobuf->maplist, iobuf->array_len * sizeof(struct page **));
if (iobuf->array_len > KIO_STATIC_PAGES)
kfree (iobuf->maplist);
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);
if (atomic_read(&kiobuf->io_count) == 0)
return;
add_wait_queue(&kiobuf->wait_queue, &wait);
repeat:
set_task_state(tsk, TASK_UNINTERRUPTIBLE);
if (atomic_read(&kiobuf->io_count) != 0) {
run_task_queue(&tq_disk);
schedule();
if (atomic_read(&kiobuf->io_count) != 0)
goto repeat;
}
tsk->state = TASK_RUNNING;
remove_wait_queue(&kiobuf->wait_queue, &wait);
}
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