ntb: Fix calculation ntb_transport_tx_free_entry()
commit 5a7693e6bbf19b22fd6c1d2c4b7beb0a03969e2c upstream.
ntb_transport_tx_free_entry() never returns 0 with the current
calculation. If head == tail, then it would return qp->tx_max_entry.
Change compare to tail >= head and when they are equal, a 0 would be
returned.
Fixes: e74bfeedad
("NTB: Add flow control to the ntb_netdev")
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: renlonglong <ren.longlong@h3c.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:

committed by
Greg Kroah-Hartman

parent
c028e90e0d
commit
3d8d13a174
@@ -2431,7 +2431,7 @@ unsigned int ntb_transport_tx_free_entry(struct ntb_transport_qp *qp)
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unsigned int head = qp->tx_index;
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unsigned int head = qp->tx_index;
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unsigned int tail = qp->remote_rx_info->entry;
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unsigned int tail = qp->remote_rx_info->entry;
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return tail > head ? tail - head : qp->tx_max_entry + tail - head;
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return tail >= head ? tail - head : qp->tx_max_entry + tail - head;
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}
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}
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EXPORT_SYMBOL_GPL(ntb_transport_tx_free_entry);
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EXPORT_SYMBOL_GPL(ntb_transport_tx_free_entry);
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