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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>
static kmem_cache_t *kiobuf_cachep;
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 int kiobuf_init(struct kiobuf *iobuf)
{
init_waitqueue_head(&iobuf->wait_queue);
iobuf->array_len = 0;
iobuf->nr_pages = 0;
iobuf->locked = 0;
iobuf->bh = NULL;
iobuf->blocks = NULL;
atomic_set(&iobuf->io_count, 0);
iobuf->end_io = NULL;
return expand_kiobuf(iobuf, KIO_STATIC_PAGES);
}
int alloc_kiobuf_bhs(struct kiobuf * kiobuf)
{
int i;
kiobuf->blocks =
kmalloc(sizeof(*kiobuf->blocks) * KIO_MAX_SECTORS, GFP_KERNEL);
if (unlikely(!kiobuf->blocks))
goto nomem;
kiobuf->bh =
kmalloc(sizeof(*kiobuf->bh) * KIO_MAX_SECTORS, GFP_KERNEL);
if (unlikely(!kiobuf->bh))
goto nomem;
for (i = 0; i < KIO_MAX_SECTORS; i++) {
kiobuf->bh[i] = kmem_cache_alloc(bh_cachep, GFP_KERNEL);
if (unlikely(!kiobuf->bh[i]))
goto nomem2;
}
return 0;
nomem2:
while (i--) {
kmem_cache_free(bh_cachep, kiobuf->bh[i]);
kiobuf->bh[i] = NULL;
}
memset(kiobuf->bh, 0, sizeof(*kiobuf->bh) * KIO_MAX_SECTORS);
nomem:
free_kiobuf_bhs(kiobuf);
return -ENOMEM;
}
void free_kiobuf_bhs(struct kiobuf * kiobuf)
{
int i;
if (kiobuf->bh) {
for (i = 0; i < KIO_MAX_SECTORS; i++)
if (kiobuf->bh[i])
kmem_cache_free(bh_cachep, kiobuf->bh[i]);
kfree(kiobuf->bh);
kiobuf->bh = NULL;
}
if (kiobuf->blocks) {
kfree(kiobuf->blocks);
kiobuf->blocks = NULL;
}
}
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, GFP_KERNEL);
if (unlikely(!iobuf))
goto nomem;
if (unlikely(kiobuf_init(iobuf)))
goto nomem2;
if (unlikely(alloc_kiobuf_bhs(iobuf)))
goto nomem2;
bufp[i] = iobuf;
}
return 0;
nomem2:
kmem_cache_free(kiobuf_cachep, iobuf);
nomem:
free_kiovec(i, bufp);
return -ENOMEM;
}
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);
kfree(iobuf->maplist);
free_kiobuf_bhs(iobuf);
kmem_cache_free(kiobuf_cachep, bufp[i]);
}
}
int expand_kiobuf(struct kiobuf *iobuf, int wanted)
{
struct page ** maplist;
if (iobuf->array_len >= wanted)
return 0;
maplist = kmalloc(wanted * sizeof(struct page **), GFP_KERNEL);
if (unlikely(!maplist))
return -ENOMEM;
/* Did it grow while we waited? */
if (unlikely(iobuf->array_len >= wanted)) {
kfree(maplist);
return 0;
}
if (iobuf->array_len) {
memcpy(maplist, iobuf->maplist, iobuf->array_len * sizeof(*maplist));
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);
}
void __init iobuf_cache_init(void)
{
kiobuf_cachep = kmem_cache_create("kiobuf", sizeof(struct kiobuf),
0, SLAB_HWCACHE_ALIGN, NULL, NULL);
if (!kiobuf_cachep)
panic("Cannot create kiobuf SLAB cache");
}
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