[dpdk-dev] [PATCH] dev: don't fail the hotplug request if device is attached in secondary

[dpdk-dev] [PATCH] dev: don't fail the hotplug request if device is attached in secondary

[Darek Stojaczyk]

Consider the following scenario:

 1) primary process (A) starts, probes the bus
 2) a secondary process (B) starts, probes the bus
 3) yet another secondary process (C) starts
 4) (C) registers the pci driver and hotplugs the device
    * an IPC attach req is sent to the primary (A)
      * (A) ignores the -EEXIST from process-local probe
      * (A) propagates the request to all secondary processes
        * (B) responds with -EEXIST
      * (A) replies to the original request with the -EEXIST
        return code
    * the -EEXIST is returned back to the user, although the
      device was successfully attached both locally and in
      all other processes

This patch makes the primary process reply with rc=0 even if
there was another secondary process with the device already
attached. The primary process already didn't reply with -EEXIST
when the device was attached locally, so now this behavior is
even more consistent. Looking by the code, this seems to be the
originally intended behavior.

Fixes: ac9e4a17370f ("eal: support attach/detach shared device from secondary")
Cc: qi.z.zhang@intel.com

Signed-off-by: Darek Stojaczyk <dariusz.stojaczyk@intel.com>
---
 lib/librte_eal/common/hotplug_mp.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/lib/librte_eal/common/hotplug_mp.c b/lib/librte_eal/common/hotplug_mp.c
index 7c9fcc46c..c0115d5f6 100644
--- a/lib/librte_eal/common/hotplug_mp.c
+++ b/lib/librte_eal/common/hotplug_mp.c
@@ -391,13 +391,13 @@ int eal_dev_hotplug_request_to_secondary(struct eal_dev_mp_req *req)
 		struct eal_dev_mp_req *resp =
 			(struct eal_dev_mp_req *)mp_reply.msgs[i].param;
 		if (resp->result != 0) {
-			req->result = resp->result;
 			if (req->t == EAL_DEV_REQ_TYPE_ATTACH &&
-				req->result != -EEXIST)
-				break;
+				resp->result == -EEXIST)
+				continue;
 			if (req->t == EAL_DEV_REQ_TYPE_DETACH &&
-				req->result != -ENOENT)
-				break;
+				resp->result == -ENOENT)
+				continue;
+			req->result = resp->result;
 		}
 	}
 
-- 
2.17.1

Re: [dpdk-dev] [PATCH] dev: don't fail the hotplug request if device is attached in secondary

[Zhang, Qi Z]

> -----Original Message-----
> From: Stojaczyk, Dariusz
> Sent: Friday, November 23, 2018 6:58 AM
> To: dev@dpdk.org
> Cc: thomas@monjalon.net; Stojaczyk, Dariusz <dariusz.stojaczyk@intel.com>;
> Zhang, Qi Z <qi.z.zhang@intel.com>
> Subject: [PATCH] dev: don't fail the hotplug request if device is attached in
> secondary
> 
> Consider the following scenario:
> 
>  1) primary process (A) starts, probes the bus
>  2) a secondary process (B) starts, probes the bus
>  3) yet another secondary process (C) starts
>  4) (C) registers the pci driver and hotplugs the device
>     * an IPC attach req is sent to the primary (A)
>       * (A) ignores the -EEXIST from process-local probe
>       * (A) propagates the request to all secondary processes
>         * (B) responds with -EEXIST
>       * (A) replies to the original request with the -EEXIST
>         return code
>     * the -EEXIST is returned back to the user, although the
>       device was successfully attached both locally and in
>       all other processes
> 
> This patch makes the primary process reply with rc=0 even if there was another
> secondary process with the device already attached. The primary process
> already didn't reply with -EEXIST when the device was attached locally, so now
> this behavior is even more consistent. Looking by the code, this seems to be the
> originally intended behavior.
> 
> Fixes: ac9e4a17370f ("eal: support attach/detach shared device from
> secondary")
> Cc: qi.z.zhang@intel.com
> 
> Signed-off-by: Darek Stojaczyk <dariusz.stojaczyk@intel.com>

Acked-by: Qi Zhang <qi.z.zhang@intel.com>

> ---
>  lib/librte_eal/common/hotplug_mp.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/lib/librte_eal/common/hotplug_mp.c
> b/lib/librte_eal/common/hotplug_mp.c
> index 7c9fcc46c..c0115d5f6 100644
> --- a/lib/librte_eal/common/hotplug_mp.c
> +++ b/lib/librte_eal/common/hotplug_mp.c
> @@ -391,13 +391,13 @@ int eal_dev_hotplug_request_to_secondary(struct
> eal_dev_mp_req *req)
>  		struct eal_dev_mp_req *resp =
>  			(struct eal_dev_mp_req *)mp_reply.msgs[i].param;
>  		if (resp->result != 0) {
> -			req->result = resp->result;
>  			if (req->t == EAL_DEV_REQ_TYPE_ATTACH &&
> -				req->result != -EEXIST)
> -				break;
> +				resp->result == -EEXIST)
> +				continue;
>  			if (req->t == EAL_DEV_REQ_TYPE_DETACH &&
> -				req->result != -ENOENT)
> -				break;
> +				resp->result == -ENOENT)
> +				continue;
> +			req->result = resp->result;	
>  		}
>  	}
> 
> --
> 2.17.1

Re: [dpdk-dev] [PATCH] dev: don't fail the hotplug request if device is attached in secondary

[Thomas Monjalon]

> > Consider the following scenario:
> > 
> >  1) primary process (A) starts, probes the bus
> >  2) a secondary process (B) starts, probes the bus
> >  3) yet another secondary process (C) starts
> >  4) (C) registers the pci driver and hotplugs the device
> >     * an IPC attach req is sent to the primary (A)
> >       * (A) ignores the -EEXIST from process-local probe
> >       * (A) propagates the request to all secondary processes
> >         * (B) responds with -EEXIST
> >       * (A) replies to the original request with the -EEXIST
> >         return code
> >     * the -EEXIST is returned back to the user, although the
> >       device was successfully attached both locally and in
> >       all other processes
> > 
> > This patch makes the primary process reply with rc=0 even if there was another
> > secondary process with the device already attached. The primary process
> > already didn't reply with -EEXIST when the device was attached locally, so now
> > this behavior is even more consistent. Looking by the code, this seems to be the
> > originally intended behavior.
> > 
> > Fixes: ac9e4a17370f ("eal: support attach/detach shared device from
> > secondary")
> > Cc: qi.z.zhang@intel.com
> > 
> > Signed-off-by: Darek Stojaczyk <dariusz.stojaczyk@intel.com>
> 
> Acked-by: Qi Zhang <qi.z.zhang@intel.com>

Applied, thanks