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aio-posix: simplify FDMonOps->update() prototype

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The AioHandler *node, bool is_new arguments are more complicated to
think about than simply being given AioHandler *old_node, AioHandler
*new_node.

Furthermore, the new Linux io_uring file descriptor monitoring mechanism
added by the new patch requires access to both the old and the new
nodes.  Make this change now in preparation.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Link: https://lore.kernel.org/r/20200305170806.1313245-5-stefanha@redhat.com
Message-Id: <20200305170806.1313245-5-stefanha@redhat.com>
This commit is contained in:
Stefan Hajnoczi 2020-03-05 17:08:03 +00:00
parent 1f050a4690
commit b321051cf4
4 changed files with 22 additions and 23 deletions
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13
include/block/aio.h
View file

@ -57,17 +57,16 @@ typedef struct {
/*
* update:
* @ctx: the AioContext
* @node: the handler
* @is_new: is the file descriptor already being monitored?
* @old_node: the existing handler or NULL if this file descriptor is being
* monitored for the first time
* @new_node: the new handler or NULL if this file descriptor is being
* removed
*
* Add/remove/modify a monitored file descriptor. There are three cases:
* 1. node->pfd.events == 0 means remove the file descriptor.
* 2. !is_new means modify an already monitored file descriptor.
* 3. is_new means add a new file descriptor.
* Add/remove/modify a monitored file descriptor.
*
* Called with ctx->list_lock acquired.
*/
void (*update)(AioContext *ctx, AioHandler *node, bool is_new);
void (*update)(AioContext *ctx, AioHandler *old_node, AioHandler *new_node);
/*
* wait:

7
util/aio-posix.c
View file

@ -139,12 +139,7 @@ void aio_set_fd_handler(AioContext *ctx,
atomic_set(&ctx->poll_disable_cnt,
atomic_read(&ctx->poll_disable_cnt) + poll_disable_change);
if (new_node) {
ctx->fdmon_ops->update(ctx, new_node, is_new);
} else if (node) {
/* Unregister deleted fd_handler */
ctx->fdmon_ops->update(ctx, node, false);
}
ctx->fdmon_ops->update(ctx, node, new_node);
qemu_lockcnt_unlock(&ctx->list_lock);
aio_notify(ctx);

21
util/fdmon-epoll.c
View file

@ -30,21 +30,24 @@ static inline int epoll_events_from_pfd(int pfd_events)
(pfd_events & G_IO_ERR ? EPOLLERR : 0);
}
static void fdmon_epoll_update(AioContext *ctx, AioHandler *node, bool is_new)
static void fdmon_epoll_update(AioContext *ctx,
AioHandler *old_node,
AioHandler *new_node)
{
struct epoll_event event;
struct epoll_event event = {
.data.ptr = new_node,
.events = new_node ? epoll_events_from_pfd(new_node->pfd.events) : 0,
};
int r;
int ctl;
if (!node->pfd.events) {
ctl = EPOLL_CTL_DEL;
if (!new_node) {
r = epoll_ctl(ctx->epollfd, EPOLL_CTL_DEL, old_node->pfd.fd, &event);
} else if (!old_node) {
r = epoll_ctl(ctx->epollfd, EPOLL_CTL_ADD, new_node->pfd.fd, &event);
} else {
event.data.ptr = node;
event.events = epoll_events_from_pfd(node->pfd.events);
ctl = is_new ? EPOLL_CTL_ADD : EPOLL_CTL_MOD;
r = epoll_ctl(ctx->epollfd, EPOLL_CTL_MOD, new_node->pfd.fd, &event);
}
r = epoll_ctl(ctx->epollfd, ctl, node->pfd.fd, &event);
if (r) {
fdmon_epoll_disable(ctx);
}

4
util/fdmon-poll.c
View file

@ -93,7 +93,9 @@ static int fdmon_poll_wait(AioContext *ctx, AioHandlerList *ready_list,
return ret;
}
static void fdmon_poll_update(AioContext *ctx, AioHandler *node, bool is_new)
static void fdmon_poll_update(AioContext *ctx,
AioHandler *old_node,
AioHandler *new_node)
{
/* Do nothing, AioHandler already contains the state we'll need */
}