Enhance force down link feature.

[ghost]

When a host is not a surviving host, but it receives the link force down massage, it should skip the link force down massage. To reinitialize the shared memory window, the driver just need to reinitialize the reserved LUT window.

[ghost]

To use the force down link feature, we should add following patch on ntb_transport.c .

diff --git a/ntb_transport.c b/ntb_transport.c
index 9878c48..8a8638d 100644
--- a/ntb_transport.c
+++ b/ntb_transport.c
@@ -700,10 +700,6 @@ static int ntb_set_mw(struct ntb_transport_ctx *nt, int num_mw,
xlat_size = round_up(size, xlat_align_size);
buff_size = round_up(size, xlat_align);

- /* No need to re-setup */
- if (mw->xlat_size == xlat_size)
- return 0;
-
if (mw->buff_size)
ntb_free_mw(nt, num_mw);

Thanks
Joey

[wesleywesley]

it is better to rework the commit message
https://www.kernel.org/doc/html/v4.16/process/submitting-patches.html#describe-your-changes
a good commit message not only make people easily understood the patch, but also smoothing the process of upstream.

[lsgunth]

I don't think I like this change. If a peer dies and comes back when the link is down, then we won't reinitialize the shared memory window as we should....

Otherwise this looks good.

[ghost]

Hi Logan,
Thanks for the comment. I have canceled this change.

In our test, we used a shell script to load the NTB and Switchtec drivers. After using the force down link, we need to add a delay between loading ntb_hw_switchtec and ntb_transport module, otherwise the NT I/O test would be fail. is it ok?

[ghost]

@wesleywesley I have updated the commit message. Please help to review it.

[wesleywesley]

@JoeyZhang-Microsemi

1. reconfigring --> reconfiguring

2. change to microchip account

3. . pls run checkpatch.pl for this patch and fix the error and warnings if any, before pull request for others review

test@server1:~/switchtec-kernel$ ~/kernel/linux-4.17.6/scripts/checkpatch.pl 0001-ntb_hw_switchtec-Optimize-function-switchtec_ntb_rei.patch
WARNING: Possible unwrapped commit description (prefer a maximum 75 chars per line)
#7:
Function switchtec_ntb_reinit_peer() is used to reinitialize the shared NTB memory window.

WARNING: Missing a blank line after declarations
#44: FILE: ntb_hw_switchtec.c:1481:

•   int rc;
  

•   dev_info(&sndev->stdev->dev, "reinitialize shared memory window\n");
  

ERROR: Missing Signed-off-by: line(s)

total: 1 errors, 2 warnings, 32 lines checked

NOTE: For some of the reported defects, checkpatch may be able to
mechanically convert to the typical style using --fix or --fix-inplace.

0001-ntb_hw_switchtec-Optimize-function-switchtec_ntb_rei.patch has style problems, please review.

NOTE: If any of the errors are false positives, please report
them to the maintainer, see CHECKPATCH in MAINTAINERS.

[ghost]

@wesleywesley Thanks for the review. I have fixed issues.

[lsgunth]

Looks good to me.