qed: Simplify request handling
Now that we process a request in the same coroutine from beginning to end and don't drop out of it any more, we can look like a proper coroutine-based driver and simply call qed_aio_next_io() and get a return value from it instead of spawning an additional coroutine that reenters the parent when it's done. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Kevin Wolf
parent
0806c3b5dd
commit
48cc565e76
101
block/qed.c
101
block/qed.c
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@ -21,10 +21,6 @@
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#include "qapi/qmp/qerror.h"
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#include "sysemu/block-backend.h"
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static const AIOCBInfo qed_aiocb_info = {
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.aiocb_size = sizeof(QEDAIOCB),
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};
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static int bdrv_qed_probe(const uint8_t *buf, int buf_size,
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const char *filename)
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{
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@ -253,13 +249,6 @@ static CachedL2Table *qed_new_l2_table(BDRVQEDState *s)
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return l2_table;
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}
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static void qed_aio_next_io(QEDAIOCB *acb);
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static void qed_aio_start_io(QEDAIOCB *acb)
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{
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qed_aio_next_io(acb);
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}
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static void qed_plug_allocating_write_reqs(BDRVQEDState *s)
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{
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assert(!s->allocating_write_reqs_plugged);
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@ -751,7 +740,7 @@ static int64_t coroutine_fn bdrv_qed_co_get_block_status(BlockDriverState *bs,
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static BDRVQEDState *acb_to_s(QEDAIOCB *acb)
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{
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return acb->common.bs->opaque;
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return acb->bs->opaque;
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}
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/**
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@ -888,28 +877,10 @@ static void qed_update_l2_table(BDRVQEDState *s, QEDTable *table, int index,
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}
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}
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static void qed_aio_complete_bh(void *opaque)
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{
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QEDAIOCB *acb = opaque;
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BDRVQEDState *s = acb_to_s(acb);
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BlockCompletionFunc *cb = acb->common.cb;
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void *user_opaque = acb->common.opaque;
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int ret = acb->bh_ret;
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qemu_aio_unref(acb);
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/* Invoke callback */
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qed_acquire(s);
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cb(user_opaque, ret);
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qed_release(s);
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}
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static void qed_aio_complete(QEDAIOCB *acb, int ret)
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static void qed_aio_complete(QEDAIOCB *acb)
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{
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BDRVQEDState *s = acb_to_s(acb);
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trace_qed_aio_complete(s, acb, ret);
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/* Free resources */
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qemu_iovec_destroy(&acb->cur_qiov);
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qed_unref_l2_cache_entry(acb->request.l2_table);
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@ -920,11 +891,6 @@ static void qed_aio_complete(QEDAIOCB *acb, int ret)
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acb->qiov->iov[0].iov_base = NULL;
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}
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/* Arrange for a bh to invoke the completion function */
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acb->bh_ret = ret;
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aio_bh_schedule_oneshot(bdrv_get_aio_context(acb->common.bs),
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qed_aio_complete_bh, acb);
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/* Start next allocating write request waiting behind this one. Note that
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* requests enqueue themselves when they first hit an unallocated cluster
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* but they wait until the entire request is finished before waking up the
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@ -1172,7 +1138,7 @@ static int qed_aio_write_inplace(QEDAIOCB *acb, uint64_t offset, size_t len)
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struct iovec *iov = acb->qiov->iov;
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if (!iov->iov_base) {
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iov->iov_base = qemu_try_blockalign(acb->common.bs, iov->iov_len);
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iov->iov_base = qemu_try_blockalign(acb->bs, iov->iov_len);
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if (iov->iov_base == NULL) {
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return -ENOMEM;
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}
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@ -1231,7 +1197,7 @@ static int qed_aio_read_data(void *opaque, int ret, uint64_t offset, size_t len)
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{
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QEDAIOCB *acb = opaque;
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BDRVQEDState *s = acb_to_s(acb);
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BlockDriverState *bs = acb->common.bs;
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BlockDriverState *bs = acb->bs;
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/* Adjust offset into cluster */
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offset += qed_offset_into_cluster(s, acb->cur_pos);
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@ -1260,7 +1226,7 @@ static int qed_aio_read_data(void *opaque, int ret, uint64_t offset, size_t len)
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/**
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* Begin next I/O or complete the request
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*/
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static void qed_aio_next_io(QEDAIOCB *acb)
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static int qed_aio_next_io(QEDAIOCB *acb)
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{
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BDRVQEDState *s = acb_to_s(acb);
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uint64_t offset;
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@ -1282,16 +1248,15 @@ static void qed_aio_next_io(QEDAIOCB *acb)
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/* Complete request */
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if (acb->cur_pos >= acb->end_pos) {
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qed_aio_complete(acb, 0);
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return;
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ret = 0;
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break;
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}
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/* Find next cluster and start I/O */
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len = acb->end_pos - acb->cur_pos;
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ret = qed_find_cluster(s, &acb->request, acb->cur_pos, &len, &offset);
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if (ret < 0) {
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qed_aio_complete(acb, ret);
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return;
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break;
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}
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if (acb->flags & QED_AIOCB_WRITE) {
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@ -1301,56 +1266,32 @@ static void qed_aio_next_io(QEDAIOCB *acb)
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}
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if (ret < 0 && ret != -EAGAIN) {
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qed_aio_complete(acb, ret);
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return;
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break;
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}
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}
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}
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typedef struct QEDRequestCo {
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Coroutine *co;
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bool done;
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int ret;
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} QEDRequestCo;
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static void qed_co_request_cb(void *opaque, int ret)
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{
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QEDRequestCo *co = opaque;
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co->done = true;
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co->ret = ret;
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qemu_coroutine_enter_if_inactive(co->co);
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trace_qed_aio_complete(s, acb, ret);
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qed_aio_complete(acb);
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return ret;
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}
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static int coroutine_fn qed_co_request(BlockDriverState *bs, int64_t sector_num,
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QEMUIOVector *qiov, int nb_sectors,
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int flags)
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{
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QEDRequestCo co = {
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.co = qemu_coroutine_self(),
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.done = false,
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QEDAIOCB acb = {
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.bs = bs,
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.cur_pos = (uint64_t) sector_num * BDRV_SECTOR_SIZE,
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.end_pos = (sector_num + nb_sectors) * BDRV_SECTOR_SIZE,
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.qiov = qiov,
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.flags = flags,
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};
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QEDAIOCB *acb = qemu_aio_get(&qed_aiocb_info, bs, qed_co_request_cb, &co);
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qemu_iovec_init(&acb.cur_qiov, qiov->niov);
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trace_qed_aio_setup(bs->opaque, acb, sector_num, nb_sectors, &co, flags);
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acb->flags = flags;
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acb->qiov = qiov;
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acb->qiov_offset = 0;
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acb->cur_pos = (uint64_t)sector_num * BDRV_SECTOR_SIZE;
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acb->end_pos = acb->cur_pos + nb_sectors * BDRV_SECTOR_SIZE;
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acb->backing_qiov = NULL;
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acb->request.l2_table = NULL;
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qemu_iovec_init(&acb->cur_qiov, qiov->niov);
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trace_qed_aio_setup(bs->opaque, &acb, sector_num, nb_sectors, NULL, flags);
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/* Start request */
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qed_aio_start_io(acb);
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if (!co.done) {
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qemu_coroutine_yield();
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}
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return co.ret;
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return qed_aio_next_io(&acb);
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}
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static int coroutine_fn bdrv_qed_co_readv(BlockDriverState *bs,
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@ -129,8 +129,7 @@ enum {
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};
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typedef struct QEDAIOCB {
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BlockAIOCB common;
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int bh_ret; /* final return status for completion bh */
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BlockDriverState *bs;
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QSIMPLEQ_ENTRY(QEDAIOCB) next; /* next request */
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int flags; /* QED_AIOCB_* bits ORed together */
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uint64_t end_pos; /* request end on block device, in bytes */
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