LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Matthew Wilcox <mawilcox@microsoft.com>
To: Hans Westgaard Ry <hans.westgaard.ry@oracle.com>,
	Doug Ledford <dledford@redhat.com>,
	Jason Gunthorpe <jgg@ziepe.ca>,
	Hakon Bugge <haakon.bugge@oracle.com>,
	Parav Pandit <parav@mellanox.com>,
	Jack Morgenstein <jackm@dev.mellanox.co.il>,
	Pravin Shedge <pravin.shedge4linux@gmail.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Jeff Layton <jlayton@kernel.org>, Wei Wang <wei.w.wang@intel.com>,
	Chris Mi <chrism@mellanox.com>,
	Eric Biggers <ebiggers@google.com>,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	Mel Gorman <mgorman@techsingularity.net>,
	"linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH v3 2/2] IB/mad: Use ID allocator routines to allocate agent number
Date: Thu, 7 Jun 2018 15:37:50 +0000	[thread overview]
Message-ID: <BL0PR2101MB088460CA4C97562CB311ED3ECB640@BL0PR2101MB0884.namprd21.prod.outlook.com> (raw)
In-Reply-To: <20180607111435.17538-3-hans.westgaard.ry@oracle.com>

Why do you need the ID to increment like this?  Why can't you just use a unique ID?

> -----Original Message-----
> From: Hans Westgaard Ry [mailto:hans.westgaard.ry@oracle.com]
> Sent: Thursday, June 7, 2018 7:15 AM
> To: Doug Ledford <dledford@redhat.com>; Jason Gunthorpe <jgg@ziepe.ca>;
> Hakon Bugge <haakon.bugge@oracle.com>; Parav Pandit
> <parav@mellanox.com>; Jack Morgenstein <jackm@dev.mellanox.co.il>; Pravin
> Shedge <pravin.shedge4linux@gmail.com>; Matthew Wilcox
> <mawilcox@microsoft.com>; Andrew Morton <akpm@linux-foundation.org>;
> Jeff Layton <jlayton@kernel.org>; Wei Wang <wei.w.wang@intel.com>; Chris
> Mi <chrism@mellanox.com>; Eric Biggers <ebiggers@google.com>; Rasmus
> Villemoes <linux@rasmusvillemoes.dk>; Mel Gorman
> <mgorman@techsingularity.net>; linux-rdma@vger.kernel.org; linux-
> kernel@vger.kernel.org
> Subject: [PATCH v3 2/2] IB/mad: Use ID allocator routines to allocate agent
> number
> 
> The agent TID is a 64 bit value split in two dwords.  The least
> significant dword is the TID running counter. The most significant
> dword is the agent number. In the CX-3 shared port model, the mlx4
> driver uses the most significant byte of the agent number to store the
> slave number, making agent numbers greater and equal to 2^24 (3 bytes)
> unusable.  The current codebase uses a variable which is incremented
> atomically for each new agent number giving too large agent numbers
> over time.  The IDA set of functions are used instead of the simple
> counter approach. This allows re-use of agent numbers.
> 
> The signature of the bug is a MAD layer that stops working and the
> console is flooded with messages like:
>  mlx4_ib: egress mad has non-null tid msb:1 class:4 slave:0
> 
> Signed-off-by: Hans Westgaard Ry <hans.westgaard.ry@oracle.com>
> ---
>  drivers/infiniband/core/mad.c | 25 +++++++++++++++++++++----
>  1 file changed, 21 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/infiniband/core/mad.c b/drivers/infiniband/core/mad.c
> index b28452a55a08..c01a2d63ffa2 100644
> --- a/drivers/infiniband/core/mad.c
> +++ b/drivers/infiniband/core/mad.c
> @@ -41,6 +41,7 @@
>  #include <linux/slab.h>
>  #include <linux/module.h>
>  #include <linux/security.h>
> +#include <linux/idr.h>
>  #include <rdma/ib_cache.h>
> 
>  #include "mad_priv.h"
> @@ -59,8 +60,7 @@ module_param_named(recv_queue_size,
> mad_recvq_size, int, 0444);
>  MODULE_PARM_DESC(recv_queue_size, "Size of receive queue in number of
> work requests");
> 
>  static struct list_head ib_mad_port_list;
> -static atomic_t ib_mad_client_id = ATOMIC_INIT(0);
> -
> +static DEFINE_IDA(ib_mad_client_ids);
>  /* Port list lock */
>  static DEFINE_SPINLOCK(ib_mad_port_list_lock);
> 
> @@ -212,7 +212,7 @@ struct ib_mad_agent *ib_register_mad_agent(struct
> ib_device *device,
>  	int ret2, qpn;
>  	unsigned long flags;
>  	u8 mgmt_class, vclass;
> -
> +	u32 ib_mad_client_id;
>  	/* Validate parameters */
>  	qpn = get_spl_qp_index(qp_type);
>  	if (qpn == -1) {
> @@ -375,9 +375,19 @@ struct ib_mad_agent *ib_register_mad_agent(struct
> ib_device *device,
>  		ret = ERR_PTR(ret2);
>  		goto error4;
>  	}
> +	ib_mad_client_id = ida_simple_get_cyclic(&ib_mad_client_ids,
> +						1,
> +						BIT(24) - 1,
> +						GFP_KERNEL);
> +	if (ib_mad_client_id < 0) {
> +		pr_err("Couldn't allocate agent tid; errcode: %#x\n",
> +			ib_mad_client_id);
> +		ret = ERR_PTR(ib_mad_client_id);
> +		goto error4;
> +	}
> +	mad_agent_priv->agent.hi_tid = ib_mad_client_id;
> 
>  	spin_lock_irqsave(&port_priv->reg_lock, flags);
> -	mad_agent_priv->agent.hi_tid =
> atomic_inc_return(&ib_mad_client_id);
> 
>  	/*
>  	 * Make sure MAD registration (if supplied)
> @@ -428,6 +438,8 @@ struct ib_mad_agent *ib_register_mad_agent(struct
> ib_device *device,
>  error5:
>  	spin_unlock_irqrestore(&port_priv->reg_lock, flags);
>  	ib_mad_agent_security_cleanup(&mad_agent_priv->agent);
> +	ida_simple_remove(&ib_mad_client_ids, ib_mad_client_id);
> +
>  error4:
>  	kfree(reg_req);
>  error3:
> @@ -576,6 +588,7 @@ static void unregister_mad_agent(struct
> ib_mad_agent_private *mad_agent_priv)
>  {
>  	struct ib_mad_port_private *port_priv;
>  	unsigned long flags;
> +	u32 ib_mad_client_id;
> 
>  	/* Note that we could still be handling received MADs */
> 
> @@ -587,6 +600,8 @@ static void unregister_mad_agent(struct
> ib_mad_agent_private *mad_agent_priv)
>  	port_priv = mad_agent_priv->qp_info->port_priv;
>  	cancel_delayed_work(&mad_agent_priv->timed_work);
> 
> +	ib_mad_client_id = mad_agent_priv->agent.hi_tid;
> +
>  	spin_lock_irqsave(&port_priv->reg_lock, flags);
>  	remove_mad_reg_req(mad_agent_priv);
>  	list_del(&mad_agent_priv->agent_list);
> @@ -602,6 +617,7 @@ static void unregister_mad_agent(struct
> ib_mad_agent_private *mad_agent_priv)
> 
>  	kfree(mad_agent_priv->reg_req);
>  	kfree(mad_agent_priv);
> +	ida_simple_remove(&ib_mad_client_ids, ib_mad_client_id);
>  }
> 
>  static void unregister_mad_snoop(struct ib_mad_snoop_private
> *mad_snoop_priv)
> @@ -3347,4 +3363,5 @@ int ib_mad_init(void)
>  void ib_mad_cleanup(void)
>  {
>  	ib_unregister_client(&mad_client);
> +	ida_destroy(&ib_mad_client_ids);
>  }
> --
> 2.14.3


  reply	other threads:[~2018-06-07 15:38 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-29  7:38 [PATCH] " Hans Westgaard Ry
2018-05-29  8:54 ` Leon Romanovsky
2018-05-29  9:54   ` Leon Romanovsky
2018-05-30  8:18     ` jackm
2018-05-29 15:49 ` Jason Gunthorpe
2018-05-29 16:16   ` Håkon Bugge
2018-05-29 16:40     ` Jason Gunthorpe
2018-05-30  7:32       ` Håkon Bugge
2018-05-30 15:15         ` Jason Gunthorpe
2018-05-30  8:02       ` jackm
2018-05-30 12:22         ` Hans Westgaard Ry
2018-05-30 15:10           ` Jason Gunthorpe
2018-05-30 20:07             ` Håkon Bugge
2018-05-30 22:09               ` Jason Gunthorpe
2018-05-31 19:54                 ` Håkon Bugge
2018-06-07 10:52 ` [PATCH v2 0/2] IB:mad " Hans Westgaard Ry
2018-06-07 10:52   ` [PATCH v2 1/2] idr: Add ida_simple_get_cyclic Hans Westgaard Ry
2018-06-07 10:52   ` [PATCH v2 2/2] IB/mad: Use ID allocator routines to allocate agent number Hans Westgaard Ry
2018-06-07 11:14 ` [PATCH v3 0/2] IB:mad " Hans Westgaard Ry
2018-06-07 11:14   ` [PATCH v3 1/2] idr: Add ida_simple_get_cyclic Hans Westgaard Ry
2018-06-07 18:50     ` Jason Gunthorpe
2018-06-07 11:14   ` [PATCH v3 2/2] IB/mad: Use ID allocator routines to allocate agent number Hans Westgaard Ry
2018-06-07 15:37     ` Matthew Wilcox [this message]
2018-06-07 17:59       ` Håkon Bugge

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=BL0PR2101MB088460CA4C97562CB311ED3ECB640@BL0PR2101MB0884.namprd21.prod.outlook.com \
    --to=mawilcox@microsoft.com \
    --cc=akpm@linux-foundation.org \
    --cc=chrism@mellanox.com \
    --cc=dledford@redhat.com \
    --cc=ebiggers@google.com \
    --cc=haakon.bugge@oracle.com \
    --cc=hans.westgaard.ry@oracle.com \
    --cc=jackm@dev.mellanox.co.il \
    --cc=jgg@ziepe.ca \
    --cc=jlayton@kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-rdma@vger.kernel.org \
    --cc=linux@rasmusvillemoes.dk \
    --cc=mgorman@techsingularity.net \
    --cc=parav@mellanox.com \
    --cc=pravin.shedge4linux@gmail.com \
    --cc=wei.w.wang@intel.com \
    --subject='RE: [PATCH v3 2/2] IB/mad: Use ID allocator routines to allocate agent number' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).