Commit b321051c authored by Stefan Hajnoczi's avatar Stefan Hajnoczi
Browse files

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



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: default avatarStefan Hajnoczi <stefanha@redhat.com>
Link: https://lore.kernel.org/r/20200305170806.1313245-5-stefanha@redhat.com
Message-Id: <20200305170806.1313245-5-stefanha@redhat.com>
parent 1f050a46

include/block/aio.h

+6 −7
Original line number Diff line number Diff line
@@ -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:

util/aio-posix.c

+1 −6
Original line number Diff line number Diff line
@@ -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);

util/fdmon-epoll.c

+12 −9
Original line number Diff line number Diff line
@@ -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);

    }

util/fdmon-poll.c

+3 −1
Original line number Diff line number Diff line
@@ -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 */

}