qemu/dma-helpers.c
Christoph Hellwig c16b5a2ca0 fully split aio_pool from BlockDriver
Now that we have a separate aio pool structure we can remove those
aio pool details from BlockDriver.

Every driver supporting AIO now needs to declare a static AIOPool
with the aiocb size and the cancellation method.  This cleans up the
current code considerably and will make it cleaner and more obvious
to support two different aio implementations behind a single
BlockDriver.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-05-27 09:46:03 -05:00

185 lines
4.7 KiB
C

/*
* DMA helper functions
*
* Copyright (c) 2009 Red Hat
*
* This work is licensed under the terms of the GNU General Public License
* (GNU GPL), version 2 or later.
*/
#include "dma.h"
#include "block_int.h"
void qemu_sglist_init(QEMUSGList *qsg, int alloc_hint)
{
qsg->sg = qemu_malloc(alloc_hint * sizeof(ScatterGatherEntry));
qsg->nsg = 0;
qsg->nalloc = alloc_hint;
qsg->size = 0;
}
void qemu_sglist_add(QEMUSGList *qsg, target_phys_addr_t base,
target_phys_addr_t len)
{
if (qsg->nsg == qsg->nalloc) {
qsg->nalloc = 2 * qsg->nalloc + 1;
qsg->sg = qemu_realloc(qsg->sg, qsg->nalloc * sizeof(ScatterGatherEntry));
}
qsg->sg[qsg->nsg].base = base;
qsg->sg[qsg->nsg].len = len;
qsg->size += len;
++qsg->nsg;
}
void qemu_sglist_destroy(QEMUSGList *qsg)
{
qemu_free(qsg->sg);
}
typedef struct {
BlockDriverAIOCB common;
BlockDriverState *bs;
BlockDriverAIOCB *acb;
QEMUSGList *sg;
uint64_t sector_num;
int is_write;
int sg_cur_index;
target_phys_addr_t sg_cur_byte;
QEMUIOVector iov;
QEMUBH *bh;
} DMAAIOCB;
static void dma_bdrv_cb(void *opaque, int ret);
static void reschedule_dma(void *opaque)
{
DMAAIOCB *dbs = (DMAAIOCB *)opaque;
qemu_bh_delete(dbs->bh);
dbs->bh = NULL;
dma_bdrv_cb(opaque, 0);
}
static void continue_after_map_failure(void *opaque)
{
DMAAIOCB *dbs = (DMAAIOCB *)opaque;
dbs->bh = qemu_bh_new(reschedule_dma, dbs);
qemu_bh_schedule(dbs->bh);
}
static void dma_bdrv_unmap(DMAAIOCB *dbs)
{
int i;
for (i = 0; i < dbs->iov.niov; ++i) {
cpu_physical_memory_unmap(dbs->iov.iov[i].iov_base,
dbs->iov.iov[i].iov_len, !dbs->is_write,
dbs->iov.iov[i].iov_len);
}
}
static void dma_bdrv_cb(void *opaque, int ret)
{
DMAAIOCB *dbs = (DMAAIOCB *)opaque;
target_phys_addr_t cur_addr, cur_len;
void *mem;
dbs->acb = NULL;
dbs->sector_num += dbs->iov.size / 512;
dma_bdrv_unmap(dbs);
qemu_iovec_reset(&dbs->iov);
if (dbs->sg_cur_index == dbs->sg->nsg || ret < 0) {
dbs->common.cb(dbs->common.opaque, ret);
qemu_iovec_destroy(&dbs->iov);
qemu_aio_release(dbs);
return;
}
while (dbs->sg_cur_index < dbs->sg->nsg) {
cur_addr = dbs->sg->sg[dbs->sg_cur_index].base + dbs->sg_cur_byte;
cur_len = dbs->sg->sg[dbs->sg_cur_index].len - dbs->sg_cur_byte;
mem = cpu_physical_memory_map(cur_addr, &cur_len, !dbs->is_write);
if (!mem)
break;
qemu_iovec_add(&dbs->iov, mem, cur_len);
dbs->sg_cur_byte += cur_len;
if (dbs->sg_cur_byte == dbs->sg->sg[dbs->sg_cur_index].len) {
dbs->sg_cur_byte = 0;
++dbs->sg_cur_index;
}
}
if (dbs->iov.size == 0) {
cpu_register_map_client(dbs, continue_after_map_failure);
return;
}
if (dbs->is_write) {
dbs->acb = bdrv_aio_writev(dbs->bs, dbs->sector_num, &dbs->iov,
dbs->iov.size / 512, dma_bdrv_cb, dbs);
} else {
dbs->acb = bdrv_aio_readv(dbs->bs, dbs->sector_num, &dbs->iov,
dbs->iov.size / 512, dma_bdrv_cb, dbs);
}
if (!dbs->acb) {
dma_bdrv_unmap(dbs);
qemu_iovec_destroy(&dbs->iov);
return;
}
}
static void dma_aio_cancel(BlockDriverAIOCB *acb)
{
DMAAIOCB *dbs = container_of(acb, DMAAIOCB, common);
if (dbs->acb) {
bdrv_aio_cancel(dbs->acb);
}
}
static AIOPool dma_aio_pool = {
.aiocb_size = sizeof(DMAAIOCB),
.cancel = dma_aio_cancel,
};
static BlockDriverAIOCB *dma_bdrv_io(
BlockDriverState *bs, QEMUSGList *sg, uint64_t sector_num,
BlockDriverCompletionFunc *cb, void *opaque,
int is_write)
{
DMAAIOCB *dbs = qemu_aio_get(&dma_aio_pool, bs, cb, opaque);
dbs->acb = NULL;
dbs->bs = bs;
dbs->sg = sg;
dbs->sector_num = sector_num;
dbs->sg_cur_index = 0;
dbs->sg_cur_byte = 0;
dbs->is_write = is_write;
dbs->bh = NULL;
qemu_iovec_init(&dbs->iov, sg->nsg);
dma_bdrv_cb(dbs, 0);
if (!dbs->acb) {
qemu_aio_release(dbs);
return NULL;
}
return &dbs->common;
}
BlockDriverAIOCB *dma_bdrv_read(BlockDriverState *bs,
QEMUSGList *sg, uint64_t sector,
void (*cb)(void *opaque, int ret), void *opaque)
{
return dma_bdrv_io(bs, sg, sector, cb, opaque, 0);
}
BlockDriverAIOCB *dma_bdrv_write(BlockDriverState *bs,
QEMUSGList *sg, uint64_t sector,
void (*cb)(void *opaque, int ret), void *opaque)
{
return dma_bdrv_io(bs, sg, sector, cb, opaque, 1);
}