From: Jason Gunthorpe <jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org> To: Devesh Sharma <devesh.sharma-1wcpHE2jlwO1Z/+hSey0Gg@public.gmane.org> Cc: Chuck Lever <chuck.lever-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>, linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Linux NFS Mailing List <linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org> Subject: Re: [PATCH v1 02/14] xprtrdma: Warn when there are orphaned IB objects Date: Wed, 6 May 2015 10:48:17 -0600 [thread overview] Message-ID: <20150506164817.GC11331@obsidianresearch.com> (raw) In-Reply-To: <CANjDDBg3Ey0DEM3n9PY9VLW+chF0=AJPghYOopo1a9vL3CKzKg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> On Wed, May 06, 2015 at 07:52:03PM +0530, Devesh Sharma wrote: > >> Should we check for EBUSY explicitly? other then this is an error in > >> vendor specific ib_dealloc_pd() > > > > Any error return means ib_dealloc_pd() has failed, right? Doesn’t that > > mean the PD is still allocated, and could cause problems later? > > Yes, you are correct, I was thinking ib_dealloc_pd() has a refcount > implemented in the core layer, thus if the PD is used by any resource, > it will always fail with -EBUSY. .. and it will not be freed, which indicates a serious bug in the caller, so the caller should respond to the failure with a BUG_ON or WARN_ON. > .With emulex adapter it is possible to fail dealloc_pd with ENOMEM or > EIO in cases where device f/w is not responding etc. this situation do > not represent PD is actually in use. This is a really bad idea. If the pd was freed and from the consumer's perspective everything is sane then it should return success. If the driver detects an internal failure, then it should move the driver to a failed state (whatever that means, but at a minimum it means the firmware state and driver state must be resync'd), and still succeed the dealloc. There is absolutely nothing the caller can do about a driver level failure here, and it doesn't indicate a caller bug. Returning ENOMEM for dealloc is what we'd call an insane API. You can't have failable memory allocations in a dealloc path. Jason -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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From: Jason Gunthorpe <jgunthorpe@obsidianresearch.com> To: Devesh Sharma <devesh.sharma@avagotech.com> Cc: Chuck Lever <chuck.lever@oracle.com>, linux-rdma@vger.kernel.org, Linux NFS Mailing List <linux-nfs@vger.kernel.org> Subject: Re: [PATCH v1 02/14] xprtrdma: Warn when there are orphaned IB objects Date: Wed, 6 May 2015 10:48:17 -0600 [thread overview] Message-ID: <20150506164817.GC11331@obsidianresearch.com> (raw) In-Reply-To: <CANjDDBg3Ey0DEM3n9PY9VLW+chF0=AJPghYOopo1a9vL3CKzKg@mail.gmail.com> On Wed, May 06, 2015 at 07:52:03PM +0530, Devesh Sharma wrote: > >> Should we check for EBUSY explicitly? other then this is an error in > >> vendor specific ib_dealloc_pd() > > > > Any error return means ib_dealloc_pd() has failed, right? Doesn’t that > > mean the PD is still allocated, and could cause problems later? > > Yes, you are correct, I was thinking ib_dealloc_pd() has a refcount > implemented in the core layer, thus if the PD is used by any resource, > it will always fail with -EBUSY. .. and it will not be freed, which indicates a serious bug in the caller, so the caller should respond to the failure with a BUG_ON or WARN_ON. > .With emulex adapter it is possible to fail dealloc_pd with ENOMEM or > EIO in cases where device f/w is not responding etc. this situation do > not represent PD is actually in use. This is a really bad idea. If the pd was freed and from the consumer's perspective everything is sane then it should return success. If the driver detects an internal failure, then it should move the driver to a failed state (whatever that means, but at a minimum it means the firmware state and driver state must be resync'd), and still succeed the dealloc. There is absolutely nothing the caller can do about a driver level failure here, and it doesn't indicate a caller bug. Returning ENOMEM for dealloc is what we'd call an insane API. You can't have failable memory allocations in a dealloc path. Jason
next prev parent reply other threads:[~2015-05-06 16:48 UTC|newest] Thread overview: 114+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-05-04 17:56 [PATCH v1 00/14] client NFS/RDMA patches for 4.2 Chuck Lever 2015-05-04 17:56 ` Chuck Lever [not found] ` <20150504174626.3483.97639.stgit-FYjufvaPoItvLzlybtyyYzGyq/o6K9yX@public.gmane.org> 2015-05-04 17:56 ` [PATCH v1 01/14] xprtrdma: Transport fault injection Chuck Lever 2015-05-04 17:56 ` Chuck Lever [not found] ` <20150504175651.3483.35554.stgit-FYjufvaPoItvLzlybtyyYzGyq/o6K9yX@public.gmane.org> 2015-05-05 13:49 ` Anna Schumaker 2015-05-05 13:49 ` Anna Schumaker [not found] ` <5548CA82.9060903-ZwjVKphTwtPQT0dZR+AlfA@public.gmane.org> 2015-05-05 13:53 ` Chuck Lever 2015-05-05 13:53 ` Chuck Lever [not found] ` <06C797AA-4E45-49DA-8CA8-2B8D22B818DB-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org> 2015-05-05 14:44 ` Anna Schumaker 2015-05-05 14:44 ` Anna Schumaker [not found] ` <5548D741.7090803-ZwjVKphTwtPQT0dZR+AlfA@public.gmane.org> 2015-05-05 15:15 ` Chuck Lever 2015-05-05 15:15 ` Chuck Lever [not found] ` <2098B4A5-48C7-4458-BAC6-10F64359C405-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org> 2015-05-05 15:16 ` Anna Schumaker 2015-05-05 15:16 ` Anna Schumaker 2015-05-05 15:10 ` Steve Wise 2015-05-05 15:10 ` Steve Wise 2015-05-04 17:57 ` [PATCH v1 02/14] xprtrdma: Warn when there are orphaned IB objects Chuck Lever 2015-05-04 17:57 ` Chuck Lever [not found] ` <20150504175700.3483.57728.stgit-FYjufvaPoItvLzlybtyyYzGyq/o6K9yX@public.gmane.org> 2015-05-06 11:37 ` Devesh Sharma 2015-05-06 11:37 ` Devesh Sharma [not found] ` <CANjDDBicLDb7K=RZB5Gqv+oACaAG8DANJX3ML971jnXd_5KEuQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> 2015-05-06 13:24 ` Chuck Lever 2015-05-06 13:24 ` Chuck Lever [not found] ` <963F9850-38D0-4434-88E8-14BC42F74499-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org> 2015-05-06 14:05 ` Sagi Grimberg 2015-05-06 14:05 ` Sagi Grimberg 2015-05-06 14:22 ` Devesh Sharma 2015-05-06 14:22 ` Devesh Sharma [not found] ` <CANjDDBg3Ey0DEM3n9PY9VLW+chF0=AJPghYOopo1a9vL3CKzKg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> 2015-05-06 16:48 ` Jason Gunthorpe [this message] 2015-05-06 16:48 ` Jason Gunthorpe [not found] ` <20150506164817.GC11331-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org> 2015-05-07 7:53 ` Devesh Sharma 2015-05-07 7:53 ` Devesh Sharma 2015-05-04 17:57 ` [PATCH v1 03/14] xprtrdma: Replace rpcrdma_rep::rr_buffer with rr_rxprt Chuck Lever 2015-05-04 17:57 ` Chuck Lever [not found] ` <20150504175711.3483.17222.stgit-FYjufvaPoItvLzlybtyyYzGyq/o6K9yX@public.gmane.org> 2015-05-07 9:38 ` Sagi Grimberg 2015-05-07 9:38 ` Sagi Grimberg [not found] ` <554B328B.9040804-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org> 2015-05-07 13:25 ` Chuck Lever 2015-05-07 13:25 ` Chuck Lever 2015-05-04 17:57 ` [PATCH v1 04/14] xprtrdma: Use ib_device pointer safely Chuck Lever 2015-05-04 17:57 ` Chuck Lever [not found] ` <20150504175720.3483.80356.stgit-FYjufvaPoItvLzlybtyyYzGyq/o6K9yX@public.gmane.org> 2015-05-07 10:00 ` Sagi Grimberg 2015-05-07 10:00 ` Sagi Grimberg [not found] ` <554B37CF.2070206-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org> 2015-05-07 13:39 ` Chuck Lever 2015-05-07 13:39 ` Chuck Lever [not found] ` <E1ADA91B-45DA-46B6-A114-E2600613969A-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org> 2015-05-07 13:56 ` Sagi Grimberg 2015-05-07 13:56 ` Sagi Grimberg [not found] ` <554B6F2A.6000608-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org> 2015-05-07 14:12 ` Chuck Lever 2015-05-07 14:12 ` Chuck Lever [not found] ` <BDE22240-DC37-4C54-B71E-D88EF54D3119-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org> 2015-05-07 15:11 ` Sagi Grimberg 2015-05-07 15:11 ` Sagi Grimberg [not found] ` <554B80B7.8090900-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org> 2015-05-11 15:22 ` Chuck Lever 2015-05-11 15:22 ` Chuck Lever 2015-05-11 18:26 ` Hefty, Sean 2015-05-11 18:26 ` Hefty, Sean [not found] ` <1828884A29C6694DAF28B7E6B8A82373A8FCE01F-P5GAC/sN6hkd3b2yrw5b5LfspsVTdybXVpNB7YpNyf8@public.gmane.org> 2015-05-11 18:57 ` Chuck Lever 2015-05-11 18:57 ` Chuck Lever 2015-05-12 10:01 ` Sagi Grimberg 2015-05-12 10:01 ` Sagi Grimberg 2015-05-04 17:57 ` [PATCH v1 05/14] xprtrdma: Introduce helpers for allocating MWs Chuck Lever 2015-05-04 17:57 ` Chuck Lever [not found] ` <20150504175730.3483.51996.stgit-FYjufvaPoItvLzlybtyyYzGyq/o6K9yX@public.gmane.org> 2015-05-07 10:16 ` Sagi Grimberg 2015-05-07 10:16 ` Sagi Grimberg 2015-05-04 17:57 ` [PATCH v1 06/14] xprtrdma: Acquire FMRs in rpcrdma_fmr_register_external() Chuck Lever 2015-05-04 17:57 ` Chuck Lever [not found] ` <20150504175739.3483.46010.stgit-FYjufvaPoItvLzlybtyyYzGyq/o6K9yX@public.gmane.org> 2015-05-07 10:15 ` Sagi Grimberg 2015-05-07 10:15 ` Sagi Grimberg 2015-05-04 17:57 ` [PATCH v1 07/14] xprtrdma: Introduce an FRMR recovery workqueue Chuck Lever 2015-05-04 17:57 ` Chuck Lever [not found] ` <20150504175749.3483.56570.stgit-FYjufvaPoItvLzlybtyyYzGyq/o6K9yX@public.gmane.org> 2015-05-07 10:37 ` Devesh Sharma 2015-05-07 10:37 ` Devesh Sharma 2015-05-04 17:57 ` [PATCH v1 08/14] xprtrdma: Acquire MRs in rpcrdma_register_external() Chuck Lever 2015-05-04 17:57 ` Chuck Lever [not found] ` <20150504175758.3483.44890.stgit-FYjufvaPoItvLzlybtyyYzGyq/o6K9yX@public.gmane.org> 2015-05-07 10:31 ` Sagi Grimberg 2015-05-07 10:31 ` Sagi Grimberg [not found] ` <554B3EEB.7070302-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org> 2015-05-08 15:24 ` Devesh Sharma 2015-05-08 15:24 ` Devesh Sharma [not found] ` <CANjDDBiGLcaAofGwz6OGEXUUE_b2rcZepv0ebvTc-XNVEBq5Mw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> 2015-05-08 15:40 ` Chuck Lever 2015-05-08 15:40 ` Chuck Lever [not found] ` <6FBAAAF3-3E70-418F-A887-C022525D6C4F-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org> 2015-05-10 10:17 ` Sagi Grimberg 2015-05-10 10:17 ` Sagi Grimberg 2015-05-04 17:58 ` [PATCH v1 09/14] xprtrdma: Remove unused LOCAL_INV recovery logic Chuck Lever 2015-05-04 17:58 ` Chuck Lever [not found] ` <20150504175808.3483.57643.stgit-FYjufvaPoItvLzlybtyyYzGyq/o6K9yX@public.gmane.org> 2015-05-07 10:35 ` Sagi Grimberg 2015-05-07 10:35 ` Sagi Grimberg [not found] ` <554B3FFA.5020101-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org> 2015-05-08 15:31 ` Devesh Sharma 2015-05-08 15:31 ` Devesh Sharma 2015-05-04 17:58 ` [PATCH v1 10/14] xprtrdma: Remove ->ro_reset Chuck Lever 2015-05-04 17:58 ` Chuck Lever [not found] ` <20150504175818.3483.22408.stgit-FYjufvaPoItvLzlybtyyYzGyq/o6K9yX@public.gmane.org> 2015-05-07 10:36 ` Sagi Grimberg 2015-05-07 10:36 ` Sagi Grimberg [not found] ` <554B402F.3000604-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org> 2015-05-08 15:33 ` Devesh Sharma 2015-05-08 15:33 ` Devesh Sharma 2015-05-04 17:58 ` [PATCH v1 11/14] xprtrdma: Remove rpcrdma_ia::ri_memreg_strategy Chuck Lever 2015-05-04 17:58 ` Chuck Lever [not found] ` <20150504175827.3483.62904.stgit-FYjufvaPoItvLzlybtyyYzGyq/o6K9yX@public.gmane.org> 2015-05-07 10:36 ` Sagi Grimberg 2015-05-07 10:36 ` Sagi Grimberg [not found] ` <554B404B.9090301-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org> 2015-05-08 15:34 ` Devesh Sharma 2015-05-08 15:34 ` Devesh Sharma 2015-05-04 17:58 ` [PATCH v1 12/14] xprtrdma: Split rb_lock Chuck Lever 2015-05-04 17:58 ` Chuck Lever [not found] ` <20150504175837.3483.28838.stgit-FYjufvaPoItvLzlybtyyYzGyq/o6K9yX@public.gmane.org> 2015-05-07 10:37 ` Sagi Grimberg 2015-05-07 10:37 ` Sagi Grimberg 2015-05-04 17:58 ` [PATCH v1 13/14] xprtrdma: Stack relief in fmr_op_map() Chuck Lever 2015-05-04 17:58 ` Chuck Lever [not found] ` <20150504175846.3483.32959.stgit-FYjufvaPoItvLzlybtyyYzGyq/o6K9yX@public.gmane.org> 2015-05-07 10:50 ` Sagi Grimberg 2015-05-07 10:50 ` Sagi Grimberg [not found] ` <554B436B.5040108-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org> 2015-05-08 15:36 ` Devesh Sharma 2015-05-08 15:36 ` Devesh Sharma 2015-05-04 17:58 ` [PATCH v1 14/14] xprtrmda: Reduce per-transport MR allocation Chuck Lever 2015-05-04 17:58 ` Chuck Lever [not found] ` <20150504175856.3483.57373.stgit-FYjufvaPoItvLzlybtyyYzGyq/o6K9yX@public.gmane.org> 2015-05-07 11:00 ` Sagi Grimberg 2015-05-07 11:00 ` Sagi Grimberg [not found] ` <554B45E7.4040902-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org> 2015-05-08 15:53 ` Devesh Sharma 2015-05-08 15:53 ` Devesh Sharma 2015-05-05 15:17 ` [PATCH v1 00/14] client NFS/RDMA patches for 4.2 Steve Wise 2015-05-05 15:17 ` Steve Wise
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