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From:   Daniel Vetter <daniel.vetter@ffwll.ch>
To:     LKML <linux-kernel@vger.kernel.org>
Cc:     linux-mm@kvack.org,
        DRI Development <dri-devel@lists.freedesktop.org>,
        Intel Graphics Development <intel-gfx@lists.freedesktop.org>,
        Daniel Vetter <daniel.vetter@ffwll.ch>,
        Jason Gunthorpe <jgg@ziepe.ca>,
        Ralph Campbell <rcampbell@nvidia.com>,
        John Hubbard <jhubbard@nvidia.com>,
        Dan Williams <dan.j.williams@intel.com>,
        Dan Carpenter <dan.carpenter@oracle.com>,
        Matthew Wilcox <willy@infradead.org>,
        Arnd Bergmann <arnd@arndb.de>,
        Balbir Singh <bsingharora@gmail.com>,
        Ira Weiny <ira.weiny@intel.com>,
        Souptick Joarder <jrdr.linux@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= <jglisse@redhat.com>,
        Daniel Vetter <daniel.vetter@intel.com>
Subject: [PATCH 5/5] mm/hmm: WARN on illegal ->sync_cpu_device_pagetables errors
Date:   Wed, 14 Aug 2019 22:20:27 +0200
Message-Id: <20190814202027.18735-6-daniel.vetter@ffwll.ch>
In-Reply-To: <20190814202027.18735-1-daniel.vetter@ffwll.ch>
References: <20190814202027.18735-1-daniel.vetter@ffwll.ch>
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Similar to the warning in the mmu notifer, warning if an hmm mirror
callback gets it's blocking vs. nonblocking handling wrong, or if it
fails with anything else than -EAGAIN.

Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: linux-mm@kvack.org
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
---
 mm/hmm.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/mm/hmm.c b/mm/hmm.c
index 16b6731a34db..52ac59384268 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -205,6 +205,9 @@ static int hmm_invalidate_range_start(struct mmu_notifier *mn,
 			ret = -EAGAIN;
 			break;
 		}
+		WARN(ret, "%pS callback failed with %d in %sblockable context\n",
+		     mirror->ops->sync_cpu_device_pagetables, ret,
+		     update.blockable ? "" : "non-");
 	}
 	up_read(&hmm->mirrors_sem);
 
-- 
2.22.0