linux-kernel - [PATCH] kernel/memremap: Remove stale devres

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Date:   Tue,  6 Mar 2018 15:56:47 +1100
From:   Oliver O'Halloran <oohall@...il.com>
To:     linux-kernel@...r.kernel.org
Cc:     linux-nvdimm@...ts.01.org, Oliver O'Halloran <oohall@...il.com>,
        Logan Gunthorpe <logang@...tatee.com>,
        Christoph Hellwig <hch@....de>,
        Dan Williams <dan.j.williams@...el.com>
Subject: [PATCH] kernel/memremap: Remove stale devres_free() call

devm_memremap_pages() was re-worked in e8d513483300 to take a caller
allocated struct dev_pagemap as a function parameter. A call to
devres_free() was left in the error cleanup path which results in
a kernel panic if the remap fails for some reason. Remove it
to fix the panic and let devm_memremap_pages() fail gracefully.

Fixes: e8d513483300 ("memremap: change devm_memremap_pages interface to use struct dev_pagemap")
Cc: Logan Gunthorpe <logang@...tatee.com>
Cc: Christoph Hellwig <hch@....de>
Cc: Dan Williams <dan.j.williams@...el.com>
Signed-off-by: Oliver O'Halloran <oohall@...il.com>
---
Both in-tree users of devm_memremap_pages() embed dev_pagemap into other
structures so this shouldn't cause any leaks. Logan's p2p series does
add one usage that assumes pgmap will be freed on error so that'll
need fixing.
---
 kernel/memremap.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/kernel/memremap.c b/kernel/memremap.c
index 4dd4274cabe2..895e6b76b25e 100644
--- a/kernel/memremap.c
+++ b/kernel/memremap.c
@@ -427,7 +427,6 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
  err_pfn_remap:
  err_radix:
 	pgmap_radix_release(res, pgoff);
-	devres_free(pgmap);
 	return ERR_PTR(error);
 }
 EXPORT_SYMBOL(devm_memremap_pages);
-- 
2.9.5