Commit bd451435 authored by Paolo Bonzini's avatar Paolo Bonzini Committed by Stefan Hajnoczi
Browse files

async: remove unnecessary inc/dec pairs 



Pull the increment/decrement pair out of aio_bh_poll and into the
callers.

Reviewed-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: default avatarFam Zheng <famz@redhat.com>
Reviewed-by: default avatarDaniel P. Berrange <berrange@redhat.com>
Message-id: 20170213135235.12274-18-pbonzini@redhat.com
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent a153bf52

util/aio-posix.c

+3 −5
Original line number Diff line number Diff line
@@ -425,9 +425,8 @@ static bool aio_dispatch_handlers(AioContext *ctx) 


void aio_dispatch(AioContext *ctx)

{

    aio_bh_poll(ctx);



    qemu_lockcnt_inc(&ctx->list_lock);

    aio_bh_poll(ctx);

    aio_dispatch_handlers(ctx);

    qemu_lockcnt_dec(&ctx->list_lock);
@@ -679,16 +678,15 @@ bool aio_poll(AioContext *ctx, bool blocking) 
    }



    npfd = 0;

    qemu_lockcnt_dec(&ctx->list_lock);



    progress |= aio_bh_poll(ctx);



    if (ret > 0) {

        qemu_lockcnt_inc(&ctx->list_lock);

        progress |= aio_dispatch_handlers(ctx);

        qemu_lockcnt_dec(&ctx->list_lock);

    }



    qemu_lockcnt_dec(&ctx->list_lock);



    progress |= timerlistgroup_run_timers(&ctx->tlg);



    return progress;

util/aio-win32.c

+4 −4
Original line number Diff line number Diff line
@@ -253,8 +253,6 @@ static bool aio_dispatch_handlers(AioContext *ctx, HANDLE event) 
    bool progress = false;

    AioHandler *tmp;



    qemu_lockcnt_inc(&ctx->list_lock);



    /*

     * We have to walk very carefully in case aio_set_fd_handler is

     * called while we're walking.
@@ -305,14 +303,15 @@ static bool aio_dispatch_handlers(AioContext *ctx, HANDLE event) 
        }

    }



    qemu_lockcnt_dec(&ctx->list_lock);

    return progress;

}



void aio_dispatch(AioContext *ctx)

{

    qemu_lockcnt_inc(&ctx->list_lock);

    aio_bh_poll(ctx);

    aio_dispatch_handlers(ctx, INVALID_HANDLE_VALUE);

    qemu_lockcnt_dec(&ctx->list_lock);

    timerlistgroup_run_timers(&ctx->tlg);

}
@@ -349,7 +348,6 @@ bool aio_poll(AioContext *ctx, bool blocking) 
        }

    }



    qemu_lockcnt_dec(&ctx->list_lock);

    first = true;



    /* ctx->notifier is always registered.  */
@@ -392,6 +390,8 @@ bool aio_poll(AioContext *ctx, bool blocking) 
        progress |= aio_dispatch_handlers(ctx, event);

    } while (count > 0);



    qemu_lockcnt_dec(&ctx->list_lock);



    progress |= timerlistgroup_run_timers(&ctx->tlg);

    return progress;

}

util/async.c

+6 −6
Original line number Diff line number Diff line
@@ -90,15 +90,16 @@ void aio_bh_call(QEMUBH *bh) 
    bh->cb(bh->opaque);

}



/* Multiple occurrences of aio_bh_poll cannot be called concurrently */

/* Multiple occurrences of aio_bh_poll cannot be called concurrently.

 * The count in ctx->list_lock is incremented before the call, and is

 * not affected by the call.

 */

int aio_bh_poll(AioContext *ctx)

{

    QEMUBH *bh, **bhp, *next;

    int ret;

    bool deleted = false;



    qemu_lockcnt_inc(&ctx->list_lock);



    ret = 0;

    for (bh = atomic_rcu_read(&ctx->first_bh); bh; bh = next) {

        next = atomic_rcu_read(&bh->next);
@@ -123,11 +124,10 @@ int aio_bh_poll(AioContext *ctx) 


    /* remove deleted bhs */

    if (!deleted) {

        qemu_lockcnt_dec(&ctx->list_lock);

        return ret;

    }



    if (qemu_lockcnt_dec_and_lock(&ctx->list_lock)) {

    if (qemu_lockcnt_dec_if_lock(&ctx->list_lock)) {

        bhp = &ctx->first_bh;

        while (*bhp) {

            bh = *bhp;
@@ -138,7 +138,7 @@ int aio_bh_poll(AioContext *ctx) 
                bhp = &bh->next;

            }

        }

        qemu_lockcnt_unlock(&ctx->list_lock);

        qemu_lockcnt_inc_and_unlock(&ctx->list_lock);

    }

    return ret;

}