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From: Dan Williams <dan.j.williams@intel.com>
To: akpm@linux-foundation.org
Cc: "Jérôme Glisse" <jglisse@redhat.com>,
	"Christoph Hellwig" <hch@lst.de>,
	"Logan Gunthorpe" <logang@deltatee.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: [PATCH v7 2/7] mm, devm_memremap_pages: Kill mapping "System RAM" support
Date: Fri, 12 Oct 2018 10:49:42 -0700	[thread overview]
Message-ID: <153936658214.1198040.2213860996894588505.stgit@dwillia2-desk3.amr.corp.intel.com> (raw)
In-Reply-To: <153936657159.1198040.4489957977352276272.stgit@dwillia2-desk3.amr.corp.intel.com>

Given the fact that devm_memremap_pages() requires a percpu_ref that is
torn down by devm_memremap_pages_release() the current support for
mapping RAM is broken.

Support for remapping "System RAM" has been broken since the beginning
and there is no existing user of this this code path, so just kill the
support and make it an explicit error.

This cleanup also simplifies a follow-on patch to fix the error path
when setting a devm release action for devm_memremap_pages_release()
fails.

Reviewed-by: "Jérôme Glisse" <jglisse@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 kernel/memremap.c |    9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/kernel/memremap.c b/kernel/memremap.c
index 1bbb2e892941..871d81bf0c69 100644
--- a/kernel/memremap.c
+++ b/kernel/memremap.c
@@ -167,15 +167,12 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
 	is_ram = region_intersects(align_start, align_size,
 		IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE);
 
-	if (is_ram == REGION_MIXED) {
-		WARN_ONCE(1, "%s attempted on mixed region %pr\n",
-				__func__, res);
+	if (is_ram != REGION_DISJOINT) {
+		WARN_ONCE(1, "%s attempted on %s region %pr\n", __func__,
+				is_ram == REGION_MIXED ? "mixed" : "ram", res);
 		return ERR_PTR(-ENXIO);
 	}
 
-	if (is_ram == REGION_INTERSECTS)
-		return __va(res->start);
-
 	if (!pgmap->ref)
 		return ERR_PTR(-EINVAL);
 


  parent reply	other threads:[~2018-10-12 18:01 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-12 17:49 [PATCH v7 0/7] mm: Merge hmm into devm_memremap_pages, mark GPL-only Dan Williams
2018-10-12 17:49 ` [PATCH v7 1/7] mm, devm_memremap_pages: Mark devm_memremap_pages() EXPORT_SYMBOL_GPL Dan Williams
2018-10-17  8:17   ` Michal Hocko
2018-10-17 16:30     ` Dan Williams
2018-10-23 17:01       ` Michal Hocko
2018-10-12 17:49 ` Dan Williams [this message]
2018-10-12 17:49 ` [PATCH v7 3/7] mm, devm_memremap_pages: Fix shutdown handling Dan Williams
2018-10-12 17:49 ` [PATCH v7 4/7] mm, devm_memremap_pages: Add MEMORY_DEVICE_PRIVATE support Dan Williams
2018-10-12 17:49 ` [PATCH v7 5/7] mm, hmm: Use devm semantics for hmm_devmem_{add, remove} Dan Williams
2018-10-12 17:50 ` [PATCH v7 6/7] mm, hmm: Replace hmm_devmem_pages_create() with devm_memremap_pages() Dan Williams
2018-10-12 17:50 ` [PATCH v7 7/7] mm, hmm: Mark hmm_devmem_{add, add_resource} EXPORT_SYMBOL_GPL Dan Williams
2018-10-12 18:14 ` [PATCH v7 0/7] mm: Merge hmm into devm_memremap_pages, mark GPL-only Jerome Glisse

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