4.14-stable review patch. If anyone has any objections, please let me know.
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From: Dave Jiang dave.jiang@intel.com
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: e74bfeedad08 ("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 --- drivers/ntb/ntb_transport.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/ntb/ntb_transport.c +++ b/drivers/ntb/ntb_transport.c @@ -2199,7 +2199,7 @@ unsigned int ntb_transport_tx_free_entry unsigned int head = qp->tx_index; unsigned int tail = qp->remote_rx_info->entry;
- return tail > head ? tail - head : qp->tx_max_entry + tail - head; + return tail >= head ? tail - head : qp->tx_max_entry + tail - head; } EXPORT_SYMBOL_GPL(ntb_transport_tx_free_entry);