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ssh: support I/O from any AioContext

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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: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20170629132749.997-12-pbonzini@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
This commit is contained in:
Paolo Bonzini 2017-06-29 15:27:49 +02:00 committed by Fam Zheng
parent f1af3251f8
commit 5aca18a4ff
1 changed files with 17 additions and 7 deletions
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24
block/ssh.c
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@ -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