-----Original Message----- From: Praveen Kumar kumarpraveen@linux.microsoft.com Sent: Monday, June 26, 2023 10:13 AM To: souradeep chakrabarti schakrabarti@linux.microsoft.com; KY Srinivasan kys@microsoft.com; Haiyang Zhang haiyangz@microsoft.com; wei.liu@kernel.org; Dexuan Cui decui@microsoft.com; davem@davemloft.net; edumazet@google.com; kuba@kernel.org; pabeni@redhat.com; Long Li longli@microsoft.com; Ajay Sharma sharmaajay@microsoft.com; leon@kernel.org; cai.huoqing@linux.dev; ssengar@linux.microsoft.com; vkuznets@redhat.com; tglx@linutronix.de; linux- hyperv@vger.kernel.org; netdev@vger.kernel.org; linux-kernel@vger.kernel.org; linux-rdma@vger.kernel.org Cc: stable@vger.kernel.org; Souradeep Chakrabarti schakrabarti@microsoft.com Subject: Re: [PATCH 2/2 V3 net] net: mana: Fix MANA VF unload when host is unresponsive
On 6/26/2023 2:50 PM, souradeep chakrabarti wrote:
From: Souradeep Chakrabarti schakrabarti@linux.microsoft.com
This is the second part of the fix.
Also this patch adds a new attribute in mana_context, which gets set when mana_hwc_send_request() hits a timeout because of host unresponsiveness. This flag then helps to avoid the timeouts in successive calls.
Fixes: ca9c54d2d6a5ab2430c4eda364c77125d62e5e0f (net: mana: Add a
driver for
Microsoft Azure Network Adapter) Signed-off-by: Souradeep Chakrabarti schakrabarti@linux.microsoft.com
V2 -> V3:
- Removed the initialization of vf_unload_timeout
- Splitted the patch in two.
- Fixed extra space from the commit message.
drivers/net/ethernet/microsoft/mana/gdma_main.c | 4 +++- drivers/net/ethernet/microsoft/mana/hw_channel.c | 12 +++++++++++- include/net/mana/mana.h | 2 ++ 3 files changed, 16 insertions(+), 2 deletions(-)
diff --git a/drivers/net/ethernet/microsoft/mana/gdma_main.c
b/drivers/net/ethernet/microsoft/mana/gdma_main.c
index 8f3f78b68592..6411f01be0d9 100644 --- a/drivers/net/ethernet/microsoft/mana/gdma_main.c +++ b/drivers/net/ethernet/microsoft/mana/gdma_main.c @@ -946,10 +946,12 @@ int mana_gd_deregister_device(struct gdma_dev
*gd)
struct gdma_context *gc = gd->gdma_context; struct gdma_general_resp resp = {}; struct gdma_general_req req = {};
struct mana_context *ac; int err;
if (gd->pdid == INVALID_PDID) return -EINVAL;
ac = gd->driver_data;
mana_gd_init_req_hdr(&req.hdr, GDMA_DEREGISTER_DEVICE,
sizeof(req),
sizeof(resp));@@ -957,7 +959,7 @@ int mana_gd_deregister_device(struct gdma_dev *gd) req.hdr.dev_id = gd->dev_id;
err = mana_gd_send_request(gc, sizeof(req), &req, sizeof(resp), &resp);
- if (err || resp.hdr.status) {
- if ((err || resp.hdr.status) && !ac->vf_unload_timeout) { dev_err(gc->dev, "Failed to deregister device: %d, 0x%x\n", err, resp.hdr.status);
With !ac->vf_unload_timeout option, this message may not be correctly showing err, status. Probably you want to add explicit information during timeouts so that it give right information ? Or have the err, status field properly updated.
if (!err)diff --git a/drivers/net/ethernet/microsoft/mana/hw_channel.c
b/drivers/net/ethernet/microsoft/mana/hw_channel.c
index 9d1507eba5b9..492cb2c6e2cb 100644 --- a/drivers/net/ethernet/microsoft/mana/hw_channel.c +++ b/drivers/net/ethernet/microsoft/mana/hw_channel.c @@ -1,8 +1,10 @@ // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause /* Copyright (c) 2021, Microsoft Corporation. */
+#include "asm-generic/errno.h" #include <net/mana/gdma.h> #include <net/mana/hw_channel.h> +#include <net/mana/mana.h>
static int mana_hwc_get_msg_index(struct hw_channel_context *hwc, u16
*msg_id)
{ @@ -786,12 +788,19 @@ int mana_hwc_send_request(struct
hw_channel_context *hwc, u32 req_len,
struct hwc_wq *txq = hwc->txq; struct gdma_req_hdr *req_msg; struct hwc_caller_ctx *ctx;
struct mana_context *ac; u32 dest_vrcq = 0; u32 dest_vrq = 0; u16 msg_id; int err;
mana_hwc_get_msg_index(hwc, &msg_id);
ac = hwc->gdma_dev->driver_data;
Is there a case where gdma_dev be invalid here ? If so, lets check the state and then proceed further ?
Yes, hwc->gdma_dev is assigned shortly after it's allocated - see the code below. So it's valid. But hwc->gdma_dev->driver_data is hwc, not "mana_context *ac". There are two gdma_dev in gdma_context: hwc & mana.
You can get ac from: hwc->gdma_dev->gdma_context->mana.driver_data Or, to avoid too many pointer deference, I suggest to put the vf_unload_timeout into gdma_context.
int mana_hwc_create_channel(struct gdma_context *gc) { hwc = kzalloc(sizeof(*hwc), GFP_KERNEL); ... gd->gdma_context = gc; gd->driver_data = hwc; hwc->gdma_dev = gd; hwc->dev = gc->dev;
Also, mana_gd_send_request/mana_hwc_send_request() is used in many places, not just unloading. Should you use timeout value 5 sec, and the vf_unload_timeout flag in unloading path only, and avoid touching other code paths? Please check with hostnet team for suggestions.
If we decide to let the vf_unload_timeout flag affect all code paths, not just unloading, then it should be renamed to hwc_timeout, and submit the second patch separately. If just use it for unloading, since mana_gd_deregister_device() is used by PF too, name it like: unload_hwc_timeout.
Thanks, -Haiyang