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50 lines
2.1 KiB
50 lines
2.1 KiB
From 2a22ee6c3ab1d761bc9c04f1e4117edd55b82f09 Mon Sep 17 00:00:00 2001
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From: Simon Gaiser <simon@invisiblethingslab.com>
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Date: Thu, 15 Mar 2018 03:43:20 +0100
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Subject: [PATCH 1/3] xen: xenbus_dev_frontend: Fix XS_TRANSACTION_END handling
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Commit fd8aa9095a95 ("xen: optimize xenbus driver for multiple
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concurrent xenstore accesses") made a subtle change to the semantic of
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xenbus_dev_request_and_reply() and xenbus_transaction_end().
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Before on an error response to XS_TRANSACTION_END
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xenbus_dev_request_and_reply() would not decrement the active
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transaction counter. But xenbus_transaction_end() has always counted the
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transaction as finished regardless of the response.
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The new behavior is that xenbus_dev_request_and_reply() and
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xenbus_transaction_end() will always count the transaction as finished
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regardless the response code (handled in xs_request_exit()).
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But xenbus_dev_frontend tries to end a transaction on closing of the
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device if the XS_TRANSACTION_END failed before. Trying to close the
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transaction twice corrupts the reference count. So fix this by also
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considering a transaction closed if we have sent XS_TRANSACTION_END once
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regardless of the return code.
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Cc: <stable@vger.kernel.org> # 4.11
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Fixes: fd8aa9095a95 ("xen: optimize xenbus driver for multiple concurrent xenstore accesses")
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Signed-off-by: Simon Gaiser <simon@invisiblethingslab.com>
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Reviewed-by: Juergen Gross <jgross@suse.com>
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Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
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---
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drivers/xen/xenbus/xenbus_dev_frontend.c | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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diff --git a/drivers/xen/xenbus/xenbus_dev_frontend.c b/drivers/xen/xenbus/xenbus_dev_frontend.c
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index a493e99bed21..81a84b3c1c50 100644
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--- a/drivers/xen/xenbus/xenbus_dev_frontend.c
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+++ b/drivers/xen/xenbus/xenbus_dev_frontend.c
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@@ -365,7 +365,7 @@ void xenbus_dev_queue_reply(struct xb_req_data *req)
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if (WARN_ON(rc))
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goto out;
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}
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- } else if (req->msg.type == XS_TRANSACTION_END) {
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+ } else if (req->type == XS_TRANSACTION_END) {
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trans = xenbus_get_transaction(u, req->msg.tx_id);
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if (WARN_ON(!trans))
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goto out;
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--
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2.16.2
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