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block/io_uring: use aio_add_sqe()

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AioContext has its own io_uring instance for file descriptor monitoring.
The disk I/O io_uring code was developed separately. Originally I
thought the characteristics of file descriptor monitoring and disk I/O
were too different, requiring separate io_uring instances.

Now it has become clear to me that it's feasible to share a single
io_uring instance for file descriptor monitoring and disk I/O. We're not
using io_uring's IOPOLL feature or anything else that would require a
separate instance.

Unify block/io_uring.c and util/fdmon-io_uring.c using the new
aio_add_sqe() API that allows user-defined io_uring sqe submission. Now
block/io_uring.c just needs to submit readv/writev/fsync and most of the
io_uring-specific logic is handled by fdmon-io_uring.c.

There are two immediate advantages:
1. Fewer system calls. There is no need to monitor the disk I/O io_uring
   ring fd from the file descriptor monitoring io_uring instance. Disk
   I/O completions are now picked up directly. Also, sqes are
   accumulated in the sq ring until the end of the event loop iteration
   and there are fewer io_uring_enter(2) syscalls.
2. Less code duplication.

Note that error_setg() messages are not supposed to end with
punctuation, so I removed a '.' for the non-io_uring build error
message.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-ID: <20251104022933.618123-15-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Stefan Hajnoczi
2025-11-03 21:29:32 -05:00
committed by Kevin Wolf
parent 1eebdab3c3
commit 047dabef97
8 changed files with 130 additions and 493 deletions
Download Patch File Download Diff File Expand all files Collapse all files

40
block/file-posix.c
View File

@@ -755,14 +755,23 @@ static int raw_open_common(BlockDriverState *bs, QDict *options,
}
#endif /* !defined(CONFIG_LINUX_AIO) */
#ifndef CONFIG_LINUX_IO_URING
if (s->use_linux_io_uring) {
#ifdef CONFIG_LINUX_IO_URING
if (!aio_has_io_uring()) {
error_setg(errp, "aio=io_uring was specified, but is not "
"available (disabled via io_uring_disabled "
"sysctl or blocked by container runtime "
"seccomp policy?)");
ret = -EINVAL;
goto fail;
}
#else
error_setg(errp, "aio=io_uring was specified, but is not supported "
"in this build.");
"in this build");
ret = -EINVAL;
goto fail;
}
#endif /* !defined(CONFIG_LINUX_IO_URING) */
}
s->has_discard = true;
s->has_write_zeroes = true;
@@ -2522,27 +2531,6 @@ static bool bdrv_qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov)
return true;
}
#ifdef CONFIG_LINUX_IO_URING
static inline bool raw_check_linux_io_uring(BDRVRawState *s)
{
Error *local_err = NULL;
AioContext *ctx;
if (!s->use_linux_io_uring) {
return false;
}
ctx = qemu_get_current_aio_context();
if (unlikely(!aio_setup_linux_io_uring(ctx, &local_err))) {
error_reportf_err(local_err, "Unable to use linux io_uring, "
"falling back to thread pool: ");
s->use_linux_io_uring = false;
return false;
}
return true;
}
#endif
#ifdef CONFIG_LINUX_AIO
static inline bool raw_check_linux_aio(BDRVRawState *s)
{
@@ -2595,7 +2583,7 @@ raw_co_prw(BlockDriverState *bs, int64_t *offset_ptr, uint64_t bytes,
if (s->needs_alignment && !bdrv_qiov_is_aligned(bs, qiov)) {
type |= QEMU_AIO_MISALIGNED;
#ifdef CONFIG_LINUX_IO_URING
} else if (raw_check_linux_io_uring(s)) {
} else if (s->use_linux_io_uring) {
assert(qiov->size == bytes);
ret = luring_co_submit(bs, s->fd, offset, qiov, type, flags);
goto out;
@@ -2692,7 +2680,7 @@ static int coroutine_fn raw_co_flush_to_disk(BlockDriverState *bs)
};
#ifdef CONFIG_LINUX_IO_URING
if (raw_check_linux_io_uring(s)) {
if (s->use_linux_io_uring) {
return luring_co_submit(bs, s->fd, 0, NULL, QEMU_AIO_FLUSH, 0);
}
#endif

489
block/io_uring.c
View File

@@ -11,28 +11,20 @@
#include "qemu/osdep.h"
#include <liburing.h>
#include "block/aio.h"
#include "qemu/queue.h"
#include "block/block.h"
#include "block/raw-aio.h"
#include "qemu/coroutine.h"
#include "qemu/defer-call.h"
#include "qapi/error.h"
#include "system/block-backend.h"
#include "trace.h"
/* Only used for assertions. */
#include "qemu/coroutine_int.h"
/* io_uring ring size */
#define MAX_ENTRIES 128
typedef struct LuringAIOCB {
typedef struct {
Coroutine *co;
struct io_uring_sqe sqeq;
ssize_t ret;
QEMUIOVector *qiov;
bool is_read;
QSIMPLEQ_ENTRY(LuringAIOCB) next;
uint64_t offset;
ssize_t ret;
int type;
int fd;
BdrvRequestFlags flags;
/*
* Buffered reads may require resubmission, see
@@ -40,36 +32,51 @@ typedef struct LuringAIOCB {
*/
int total_read;
QEMUIOVector resubmit_qiov;
} LuringAIOCB;
typedef struct LuringQueue {
unsigned int in_queue;
unsigned int in_flight;
bool blocked;
QSIMPLEQ_HEAD(, LuringAIOCB) submit_queue;
} LuringQueue;
CqeHandler cqe_handler;
} LuringRequest;
struct LuringState {
AioContext *aio_context;
struct io_uring ring;
/* No locking required, only accessed from AioContext home thread */
LuringQueue io_q;
QEMUBH *completion_bh;
};
/**
* luring_resubmit:
*
* Resubmit a request by appending it to submit_queue. The caller must ensure
* that ioq_submit() is called later so that submit_queue requests are started.
*/
static void luring_resubmit(LuringState *s, LuringAIOCB *luringcb)
static void luring_prep_sqe(struct io_uring_sqe *sqe, void *opaque)
{
QSIMPLEQ_INSERT_TAIL(&s->io_q.submit_queue, luringcb, next);
s->io_q.in_queue++;
LuringRequest *req = opaque;
QEMUIOVector *qiov = req->qiov;
uint64_t offset = req->offset;
int fd = req->fd;
BdrvRequestFlags flags = req->flags;
switch (req->type) {
case QEMU_AIO_WRITE:
#ifdef HAVE_IO_URING_PREP_WRITEV2
{
int luring_flags = (flags & BDRV_REQ_FUA) ? RWF_DSYNC : 0;
io_uring_prep_writev2(sqe, fd, qiov->iov,
qiov->niov, offset, luring_flags);
}
#else
assert(flags == 0);
io_uring_prep_writev(sqe, fd, qiov->iov, qiov->niov, offset);
#endif
break;
case QEMU_AIO_ZONE_APPEND:
io_uring_prep_writev(sqe, fd, qiov->iov, qiov->niov, offset);
break;
case QEMU_AIO_READ:
{
if (req->resubmit_qiov.iov != NULL) {
qiov = &req->resubmit_qiov;
}
io_uring_prep_readv(sqe, fd, qiov->iov, qiov->niov,
offset + req->total_read);
break;
}
case QEMU_AIO_FLUSH:
io_uring_prep_fsync(sqe, fd, IORING_FSYNC_DATASYNC);
break;
default:
fprintf(stderr, "%s: invalid AIO request type, aborting 0x%x.\n",
__func__, req->type);
abort();
}
}
/**
@@ -78,385 +85,115 @@ static void luring_resubmit(LuringState *s, LuringAIOCB *luringcb)
* Short reads are rare but may occur. The remaining read request needs to be
* resubmitted.
*/
static void luring_resubmit_short_read(LuringState *s, LuringAIOCB *luringcb,
int nread)
static void luring_resubmit_short_read(LuringRequest *req, int nread)
{
QEMUIOVector *resubmit_qiov;
size_t remaining;
trace_luring_resubmit_short_read(s, luringcb, nread);
trace_luring_resubmit_short_read(req, nread);
/* Update read position */
luringcb->total_read += nread;
remaining = luringcb->qiov->size - luringcb->total_read;
req->total_read += nread;
remaining = req->qiov->size - req->total_read;
/* Shorten qiov */
resubmit_qiov = &luringcb->resubmit_qiov;
resubmit_qiov = &req->resubmit_qiov;
if (resubmit_qiov->iov == NULL) {
qemu_iovec_init(resubmit_qiov, luringcb->qiov->niov);
qemu_iovec_init(resubmit_qiov, req->qiov->niov);
} else {
qemu_iovec_reset(resubmit_qiov);
}
qemu_iovec_concat(resubmit_qiov, luringcb->qiov, luringcb->total_read,
remaining);
qemu_iovec_concat(resubmit_qiov, req->qiov, req->total_read, remaining);
/* Update sqe */
luringcb->sqeq.off += nread;
luringcb->sqeq.addr = (uintptr_t)luringcb->resubmit_qiov.iov;
luringcb->sqeq.len = luringcb->resubmit_qiov.niov;
luring_resubmit(s, luringcb);
aio_add_sqe(luring_prep_sqe, req, &req->cqe_handler);
}
/**
* luring_process_completions:
* @s: AIO state
*
* Fetches completed I/O requests, consumes cqes and invokes their callbacks
* The function is somewhat tricky because it supports nested event loops, for
* example when a request callback invokes aio_poll().
*
* Function schedules BH completion so it can be called again in a nested
* event loop. When there are no events left to complete the BH is being
* canceled.
*
*/
static void luring_process_completions(LuringState *s)
static void luring_cqe_handler(CqeHandler *cqe_handler)
{
struct io_uring_cqe *cqes;
int total_bytes;
LuringRequest *req = container_of(cqe_handler, LuringRequest, cqe_handler);
int ret = cqe_handler->cqe.res;
defer_call_begin();
trace_luring_cqe_handler(req, ret);
/*
* Request completion callbacks can run the nested event loop.
* Schedule ourselves so the nested event loop will "see" remaining
* completed requests and process them. Without this, completion
* callbacks that wait for other requests using a nested event loop
* would hang forever.
*
* This workaround is needed because io_uring uses poll_wait, which
* is woken up when new events are added to the uring, thus polling on
* the same uring fd will block unless more events are received.
*
* Other leaf block drivers (drivers that access the data themselves)
* are networking based, so they poll sockets for data and run the
* correct coroutine.
*/
qemu_bh_schedule(s->completion_bh);
while (io_uring_peek_cqe(&s->ring, &cqes) == 0) {
LuringAIOCB *luringcb;
int ret;
if (!cqes) {
break;
if (ret < 0) {
/*
* Only writev/readv/fsync requests on regular files or host block
* devices are submitted. Therefore -EAGAIN is not expected but it's
* known to happen sometimes with Linux SCSI. Submit again and hope
* the request completes successfully.
*
* For more information, see:
* https://lore.kernel.org/io-uring/20210727165811.284510-3-axboe@kernel.dk/T/#u
*
* If the code is changed to submit other types of requests in the
* future, then this workaround may need to be extended to deal with
* genuine -EAGAIN results that should not be resubmitted
* immediately.
*/
if (ret == -EINTR || ret == -EAGAIN) {
aio_add_sqe(luring_prep_sqe, req, &req->cqe_handler);
return;
}
luringcb = io_uring_cqe_get_data(cqes);
ret = cqes->res;
io_uring_cqe_seen(&s->ring, cqes);
cqes = NULL;
/* Change counters one-by-one because we can be nested. */
s->io_q.in_flight--;
trace_luring_process_completion(s, luringcb, ret);
} else if (req->qiov) {
/* total_read is non-zero only for resubmitted read requests */
total_bytes = ret + luringcb->total_read;
int total_bytes = ret + req->total_read;
if (ret < 0) {
/*
* Only writev/readv/fsync requests on regular files or host block
* devices are submitted. Therefore -EAGAIN is not expected but it's
* known to happen sometimes with Linux SCSI. Submit again and hope
* the request completes successfully.
*
* For more information, see:
* https://lore.kernel.org/io-uring/20210727165811.284510-3-axboe@kernel.dk/T/#u
*
* If the code is changed to submit other types of requests in the
* future, then this workaround may need to be extended to deal with
* genuine -EAGAIN results that should not be resubmitted
* immediately.
*/
if (ret == -EINTR || ret == -EAGAIN) {
luring_resubmit(s, luringcb);
continue;
}
} else if (!luringcb->qiov) {
goto end;
} else if (total_bytes == luringcb->qiov->size) {
if (total_bytes == req->qiov->size) {
ret = 0;
/* Only read/write */
} else {
/* Short Read/Write */
if (luringcb->is_read) {
if (req->type == QEMU_AIO_READ) {
if (ret > 0) {
luring_resubmit_short_read(s, luringcb, ret);
continue;
} else {
/* Pad with zeroes */
qemu_iovec_memset(luringcb->qiov, total_bytes, 0,
luringcb->qiov->size - total_bytes);
ret = 0;
luring_resubmit_short_read(req, ret);
return;
}
/* Pad with zeroes */
qemu_iovec_memset(req->qiov, total_bytes, 0,
req->qiov->size - total_bytes);
ret = 0;
} else {
ret = -ENOSPC;
}
}
end:
luringcb->ret = ret;
qemu_iovec_destroy(&luringcb->resubmit_qiov);
/*
* If the coroutine is already entered it must be in ioq_submit()
* and will notice luringcb->ret has been filled in when it
* eventually runs later. Coroutines cannot be entered recursively
* so avoid doing that!
*/
assert(luringcb->co->ctx == s->aio_context);
if (!qemu_coroutine_entered(luringcb->co)) {
aio_co_wake(luringcb->co);
}
}
qemu_bh_cancel(s->completion_bh);
req->ret = ret;
qemu_iovec_destroy(&req->resubmit_qiov);
defer_call_end();
}
static int ioq_submit(LuringState *s)
{
int ret = 0;
LuringAIOCB *luringcb, *luringcb_next;
while (s->io_q.in_queue > 0) {
/*
* Try to fetch sqes from the ring for requests waiting in
* the overflow queue
*/
QSIMPLEQ_FOREACH_SAFE(luringcb, &s->io_q.submit_queue, next,
luringcb_next) {
struct io_uring_sqe *sqes = io_uring_get_sqe(&s->ring);
if (!sqes) {
break;
}
/* Prep sqe for submission */
*sqes = luringcb->sqeq;
QSIMPLEQ_REMOVE_HEAD(&s->io_q.submit_queue, next);
}
ret = io_uring_submit(&s->ring);
trace_luring_io_uring_submit(s, ret);
/* Prevent infinite loop if submission is refused */
if (ret <= 0) {
if (ret == -EAGAIN || ret == -EINTR) {
continue;
}
break;
}
s->io_q.in_flight += ret;
s->io_q.in_queue -= ret;
}
s->io_q.blocked = (s->io_q.in_queue > 0);
if (s->io_q.in_flight) {
/*
* We can try to complete something just right away if there are
* still requests in-flight.
*/
luring_process_completions(s);
}
return ret;
}
static void luring_process_completions_and_submit(LuringState *s)
{
luring_process_completions(s);
if (s->io_q.in_queue > 0) {
ioq_submit(s);
/*
* If the coroutine is already entered it must be in luring_co_submit() and
* will notice req->ret has been filled in when it eventually runs later.
* Coroutines cannot be entered recursively so avoid doing that!
*/
if (!qemu_coroutine_entered(req->co)) {
aio_co_wake(req->co);
}
}
static void qemu_luring_completion_bh(void *opaque)
int coroutine_fn luring_co_submit(BlockDriverState *bs, int fd,
uint64_t offset, QEMUIOVector *qiov,
int type, BdrvRequestFlags flags)
{
LuringState *s = opaque;
luring_process_completions_and_submit(s);
}
static void qemu_luring_completion_cb(void *opaque)
{
LuringState *s = opaque;
luring_process_completions_and_submit(s);
}
static bool qemu_luring_poll_cb(void *opaque)
{
LuringState *s = opaque;
return io_uring_cq_ready(&s->ring);
}
static void qemu_luring_poll_ready(void *opaque)
{
LuringState *s = opaque;
luring_process_completions_and_submit(s);
}
static void ioq_init(LuringQueue *io_q)
{
QSIMPLEQ_INIT(&io_q->submit_queue);
io_q->in_queue = 0;
io_q->in_flight = 0;
io_q->blocked = false;
}
static void luring_deferred_fn(void *opaque)
{
LuringState *s = opaque;
trace_luring_unplug_fn(s, s->io_q.blocked, s->io_q.in_queue,
s->io_q.in_flight);
if (!s->io_q.blocked && s->io_q.in_queue > 0) {
ioq_submit(s);
}
}
/**
* luring_do_submit:
* @fd: file descriptor for I/O
* @luringcb: AIO control block
* @s: AIO state
* @offset: offset for request
* @type: type of request
*
* Fetches sqes from ring, adds to pending queue and preps them
*
*/
static int luring_do_submit(int fd, LuringAIOCB *luringcb, LuringState *s,
uint64_t offset, int type, BdrvRequestFlags flags)
{
int ret;
struct io_uring_sqe *sqes = &luringcb->sqeq;
switch (type) {
case QEMU_AIO_WRITE:
#ifdef HAVE_IO_URING_PREP_WRITEV2
{
int luring_flags = (flags & BDRV_REQ_FUA) ? RWF_DSYNC : 0;
io_uring_prep_writev2(sqes, fd, luringcb->qiov->iov,
luringcb->qiov->niov, offset, luring_flags);
}
#else
assert(flags == 0);
io_uring_prep_writev(sqes, fd, luringcb->qiov->iov,
luringcb->qiov->niov, offset);
#endif
break;
case QEMU_AIO_ZONE_APPEND:
io_uring_prep_writev(sqes, fd, luringcb->qiov->iov,
luringcb->qiov->niov, offset);
break;
case QEMU_AIO_READ:
io_uring_prep_readv(sqes, fd, luringcb->qiov->iov,
luringcb->qiov->niov, offset);
break;
case QEMU_AIO_FLUSH:
io_uring_prep_fsync(sqes, fd, IORING_FSYNC_DATASYNC);
break;
default:
fprintf(stderr, "%s: invalid AIO request type, aborting 0x%x.\n",
__func__, type);
abort();
}
io_uring_sqe_set_data(sqes, luringcb);
QSIMPLEQ_INSERT_TAIL(&s->io_q.submit_queue, luringcb, next);
s->io_q.in_queue++;
trace_luring_do_submit(s, s->io_q.blocked, s->io_q.in_queue,
s->io_q.in_flight);
if (!s->io_q.blocked) {
if (s->io_q.in_flight + s->io_q.in_queue >= MAX_ENTRIES) {
ret = ioq_submit(s);
trace_luring_do_submit_done(s, ret);
return ret;
}
defer_call(luring_deferred_fn, s);
}
return 0;
}
int coroutine_fn luring_co_submit(BlockDriverState *bs, int fd, uint64_t offset,
QEMUIOVector *qiov, int type,
BdrvRequestFlags flags)
{
int ret;
AioContext *ctx = qemu_get_current_aio_context();
LuringState *s = aio_get_linux_io_uring(ctx);
LuringAIOCB luringcb = {
LuringRequest req = {
.co = qemu_coroutine_self(),
.ret = -EINPROGRESS,
.qiov = qiov,
.is_read = (type == QEMU_AIO_READ),
.ret = -EINPROGRESS,
.type = type,
.fd = fd,
.offset = offset,
.flags = flags,
};
trace_luring_co_submit(bs, s, &luringcb, fd, offset, qiov ? qiov->size : 0,
type);
ret = luring_do_submit(fd, &luringcb, s, offset, type, flags);
if (ret < 0) {
return ret;
}
req.cqe_handler.cb = luring_cqe_handler;
if (luringcb.ret == -EINPROGRESS) {
trace_luring_co_submit(bs, &req, fd, offset, qiov ? qiov->size : 0, type);
aio_add_sqe(luring_prep_sqe, &req, &req.cqe_handler);
if (req.ret == -EINPROGRESS) {
qemu_coroutine_yield();
}
return luringcb.ret;
}
void luring_detach_aio_context(LuringState *s, AioContext *old_context)
{
aio_set_fd_handler(old_context, s->ring.ring_fd,
NULL, NULL, NULL, NULL, s);
qemu_bh_delete(s->completion_bh);
s->aio_context = NULL;
}
void luring_attach_aio_context(LuringState *s, AioContext *new_context)
{
s->aio_context = new_context;
s->completion_bh = aio_bh_new(new_context, qemu_luring_completion_bh, s);
aio_set_fd_handler(s->aio_context, s->ring.ring_fd,
qemu_luring_completion_cb, NULL,
qemu_luring_poll_cb, qemu_luring_poll_ready, s);
}
LuringState *luring_init(Error **errp)
{
int rc;
LuringState *s = g_new0(LuringState, 1);
struct io_uring *ring = &s->ring;
trace_luring_init_state(s, sizeof(*s));
rc = io_uring_queue_init(MAX_ENTRIES, ring, 0);
if (rc < 0) {
error_setg_errno(errp, -rc, "failed to init linux io_uring ring");
g_free(s);
return NULL;
}
ioq_init(&s->io_q);
return s;
}
void luring_cleanup(LuringState *s)
{
io_uring_queue_exit(&s->ring);
trace_luring_cleanup_state(s);
g_free(s);
return req.ret;
}
bool luring_has_fua(void)

12
block/trace-events
View File

@@ -62,15 +62,9 @@ qmp_block_stream(void *bs) "bs %p"
file_paio_submit(void *acb, void *opaque, int64_t offset, int count, int type) "acb %p opaque %p offset %"PRId64" count %d type %d"
# io_uring.c
luring_init_state(void *s, size_t size) "s %p size %zu"
luring_cleanup_state(void *s) "%p freed"
luring_unplug_fn(void *s, int blocked, int queued, int inflight) "LuringState %p blocked %d queued %d inflight %d"
luring_do_submit(void *s, int blocked, int queued, int inflight) "LuringState %p blocked %d queued %d inflight %d"
luring_do_submit_done(void *s, int ret) "LuringState %p submitted to kernel %d"
luring_co_submit(void *bs, void *s, void *luringcb, int fd, uint64_t offset, size_t nbytes, int type) "bs %p s %p luringcb %p fd %d offset %" PRId64 " nbytes %zd type %d"
luring_process_completion(void *s, void *aiocb, int ret) "LuringState %p luringcb %p ret %d"
luring_io_uring_submit(void *s, int ret) "LuringState %p ret %d"
luring_resubmit_short_read(void *s, void *luringcb, int nread) "LuringState %p luringcb %p nread %d"
luring_cqe_handler(void *req, int ret) "req %p ret %d"
luring_co_submit(void *bs, void *req, int fd, uint64_t offset, size_t nbytes, int type) "bs %p req %p fd %d offset %" PRId64 " nbytes %zd type %d"
luring_resubmit_short_read(void *req, int nread) "req %p nread %d"
# qcow2.c
qcow2_add_task(void *co, void *bs, void *pool, const char *action, int cluster_type, uint64_t host_offset, uint64_t offset, uint64_t bytes, void *qiov, size_t qiov_offset) "co %p bs %p pool %p: %s: cluster_type %d file_cluster_offset %" PRIu64 " offset %" PRIu64 " bytes %" PRIu64 " qiov %p qiov_offset %zu"

7
include/block/aio.h
View File

@@ -310,8 +310,6 @@ struct AioContext {
struct LinuxAioState *linux_aio;
#endif
#ifdef CONFIG_LINUX_IO_URING
LuringState *linux_io_uring;
/* State for file descriptor monitoring using Linux io_uring */
struct io_uring fdmon_io_uring;
AioHandlerSList submit_list;
@@ -615,11 +613,6 @@ struct LinuxAioState *aio_setup_linux_aio(AioContext *ctx, Error **errp);
/* Return the LinuxAioState bound to this AioContext */
struct LinuxAioState *aio_get_linux_aio(AioContext *ctx);
/* Setup the LuringState bound to this AioContext */
LuringState *aio_setup_linux_io_uring(AioContext *ctx, Error **errp);
/* Return the LuringState bound to this AioContext */
LuringState *aio_get_linux_io_uring(AioContext *ctx);
/**
* aio_timer_new_with_attrs:
* @ctx: the aio context

5
include/block/raw-aio.h
View File

@@ -74,15 +74,10 @@ static inline bool laio_has_fua(void)
#endif
/* io_uring.c - Linux io_uring implementation */
#ifdef CONFIG_LINUX_IO_URING
LuringState *luring_init(Error **errp);
void luring_cleanup(LuringState *s);
/* luring_co_submit: submit I/O requests in the thread's current AioContext. */
int coroutine_fn luring_co_submit(BlockDriverState *bs, int fd, uint64_t offset,
QEMUIOVector *qiov, int type,
BdrvRequestFlags flags);
void luring_detach_aio_context(LuringState *s, AioContext *old_context);
void luring_attach_aio_context(LuringState *s, AioContext *new_context);
bool luring_has_fua(void);
#else
static inline bool luring_has_fua(void)

32
stubs/io_uring.c
View File

@@ -1,32 +0,0 @@
/*
* Linux io_uring support.
*
* Copyright (C) 2009 IBM, Corp.
* Copyright (C) 2009 Red Hat, Inc.
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "block/aio.h"
#include "block/raw-aio.h"
void luring_detach_aio_context(LuringState *s, AioContext *old_context)
{
abort();
}
void luring_attach_aio_context(LuringState *s, AioContext *new_context)
{
abort();
}
LuringState *luring_init(Error **errp)
{
abort();
}
void luring_cleanup(LuringState *s)
{
abort();
}

3
stubs/meson.build
View File

@@ -32,9 +32,6 @@ if have_block or have_ga
stub_ss.add(files('cpus-virtual-clock.c'))
stub_ss.add(files('icount.c'))
stub_ss.add(files('graph-lock.c'))
if linux_io_uring.found()
stub_ss.add(files('io_uring.c'))
endif
if libaio.found()
stub_ss.add(files('linux-aio.c'))
endif

35
util/async.c
View File

@@ -386,14 +386,6 @@ aio_ctx_finalize(GSource *source)
}
#endif
#ifdef CONFIG_LINUX_IO_URING
if (ctx->linux_io_uring) {
luring_detach_aio_context(ctx->linux_io_uring, ctx);
luring_cleanup(ctx->linux_io_uring);
ctx->linux_io_uring = NULL;
}
#endif
assert(QSLIST_EMPTY(&ctx->scheduled_coroutines));
qemu_bh_delete(ctx->co_schedule_bh);
@@ -469,29 +461,6 @@ LinuxAioState *aio_get_linux_aio(AioContext *ctx)
}
#endif
#ifdef CONFIG_LINUX_IO_URING
LuringState *aio_setup_linux_io_uring(AioContext *ctx, Error **errp)
{
if (ctx->linux_io_uring) {
return ctx->linux_io_uring;
}
ctx->linux_io_uring = luring_init(errp);
if (!ctx->linux_io_uring) {
return NULL;
}
luring_attach_aio_context(ctx->linux_io_uring, ctx);
return ctx->linux_io_uring;
}
LuringState *aio_get_linux_io_uring(AioContext *ctx)
{
assert(ctx->linux_io_uring);
return ctx->linux_io_uring;
}
#endif
void aio_notify(AioContext *ctx)
{
/*
@@ -631,10 +600,6 @@ AioContext *aio_context_new(Error **errp)
ctx->linux_aio = NULL;
#endif
#ifdef CONFIG_LINUX_IO_URING
ctx->linux_io_uring = NULL;
#endif
ctx->thread_pool = NULL;
qemu_rec_mutex_init(&ctx->lock);
timerlistgroup_init(&ctx->tlg, aio_timerlist_notify, ctx);