Commit 5aca18a4 authored by Paolo Bonzini's avatar Paolo Bonzini Committed by Fam Zheng
Browse files

ssh: support I/O from any AioContext 



The coroutine may run in a different AioContext, causing the
fd handler to busy wait.  Fix this by resetting the handler
in restart_coroutine, before the coroutine is restarted.

Reviewed-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: default avatarFam Zheng <famz@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Message-Id: <20170629132749.997-12-pbonzini@redhat.com>
Signed-off-by: default avatarFam Zheng <famz@redhat.com>
parent f1af3251

block/ssh.c

+17 −7
Original line number Diff line number Diff line
@@ -888,13 +888,22 @@ static int ssh_has_zero_init(BlockDriverState *bs) 
    return has_zero_init;

}



typedef struct BDRVSSHRestart {

    BlockDriverState *bs;

    Coroutine *co;

} BDRVSSHRestart;



static void restart_coroutine(void *opaque)

{

    Coroutine *co = opaque;

    BDRVSSHRestart *restart = opaque;

    BlockDriverState *bs = restart->bs;

    BDRVSSHState *s = bs->opaque;

    AioContext *ctx = bdrv_get_aio_context(bs);



    DPRINTF("co=%p", co);

    DPRINTF("co=%p", restart->co);

    aio_set_fd_handler(ctx, s->sock, false, NULL, NULL, NULL, NULL);



    aio_co_wake(co);

    aio_co_wake(restart->co);

}



/* A non-blocking call returned EAGAIN, so yield, ensuring the
@@ -905,7 +914,10 @@ static coroutine_fn void co_yield(BDRVSSHState *s, BlockDriverState *bs) 
{

    int r;

    IOHandler *rd_handler = NULL, *wr_handler = NULL;

    Coroutine *co = qemu_coroutine_self();

    BDRVSSHRestart restart = {

        .bs = bs,

        .co = qemu_coroutine_self()

    };



    r = libssh2_session_block_directions(s->session);
@@ -920,11 +932,9 @@ static coroutine_fn void co_yield(BDRVSSHState *s, BlockDriverState *bs) 
            rd_handler, wr_handler);



    aio_set_fd_handler(bdrv_get_aio_context(bs), s->sock,

                       false, rd_handler, wr_handler, NULL, co);

                       false, rd_handler, wr_handler, NULL, &restart);

    qemu_coroutine_yield();

    DPRINTF("s->sock=%d - back", s->sock);

    aio_set_fd_handler(bdrv_get_aio_context(bs), s->sock, false,

                       NULL, NULL, NULL, NULL);

}



/* SFTP has a function `libssh2_sftp_seek64' which seeks to a position