From 4c9e7aacb6a6334168a81b83819fb5cb088d2fb3 Mon Sep 17 00:00:00 2001 From: Dean Luick Date: Thu, 18 Feb 2016 11:12:08 -0800 Subject: [PATCH] staging/rdma/hfi1: Fix xmit discard error weight Count only the errors that apply to xmit discards. Update the comment to better explain the limitations of the count. Reviewed-by: Dennis Dalessandro Signed-off-by: Dean Luick Signed-off-by: Jubin John Signed-off-by: Doug Ledford --- drivers/staging/rdma/hfi1/chip.c | 26 +++++++++++++++++++++----- 1 file changed, 21 insertions(+), 5 deletions(-) diff --git a/drivers/staging/rdma/hfi1/chip.c b/drivers/staging/rdma/hfi1/chip.c index 93bf465dccbe..6e44d52e3330 100644 --- a/drivers/staging/rdma/hfi1/chip.c +++ b/drivers/staging/rdma/hfi1/chip.c @@ -5566,12 +5566,28 @@ static void handle_send_egress_err_info(struct hfi1_devdata *dd, int weight, i; /* - * Count all, in case multiple bits are set. Reminder: - * since there is only one info register for many sources, - * these may be attributed to the wrong VL if they occur - * too close together. + * Count all applicable bits as individual errors and + * attribute them to the packet that triggered this handler. + * This may not be completely accurate due to limitations + * on the available hardware error information. There is + * a single information register and any number of error + * packets may have occurred and contributed to it before + * this routine is called. This means that: + * a) If multiple packets with the same error occur before + * this routine is called, earlier packets are missed. + * There is only a single bit for each error type. + * b) Errors may not be attributed to the correct VL. + * The driver is attributing all bits in the info register + * to the packet that triggered this call, but bits + * could be an accumulation of different packets with + * different VLs. + * c) A single error packet may have multiple counts attached + * to it. There is no way for the driver to know if + * multiple bits set in the info register are due to a + * single packet or multiple packets. The driver assumes + * multiple packets. */ - weight = hweight64(info); + weight = hweight64(info & PORT_DISCARD_EGRESS_ERRS); for (i = 0; i < weight; i++) { __count_port_discards(ppd); if (vl >= 0 && vl < TXE_NUM_DATA_VL) -- 2.20.1