request for 4.14-stable: 77dd66a3c67c ("mm: Fix devm_memremap_pages() collision handling")

[Sudip Mukherjee <sudipm.mukherjee@gmail.com>]

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Hi Greg,

This was missing in 4.14-stable. Please apply to your queue.

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Regards
Sudip

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>From 25c1cf7b4a0e7fa16c9529aca22b951b45d0fd42 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jan=20H=2E=20Sch=C3=B6nherr?= <jschoenh@amazon.de>
Date: Fri, 19 Jan 2018 16:26:33 -0800
Subject: [PATCH] mm: Fix devm_memremap_pages() collision handling
MIME-Version: 1.0
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commit 77dd66a3c67c93ab401ccc15efff25578be281fd upstream

If devm_memremap_pages() detects a collision while adding entries
to the radix-tree, we call pgmap_radix_release(). Unfortunately,
the function removes *all* entries for the range -- including the
entries that caused the collision in the first place.

Modify pgmap_radix_release() to take an additional argument to
indicate where to stop, so that only newly added entries are removed
from the tree.

Cc: <stable@vger.kernel.org>
Fixes: 9476df7d80df ("mm: introduce find_dev_pagemap()")
Signed-off-by: Jan H. Sch�nherr <jschoenh@amazon.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
---
 kernel/memremap.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/kernel/memremap.c b/kernel/memremap.c
index 4712ce646e04..2b136d4988f7 100644
--- a/kernel/memremap.c
+++ b/kernel/memremap.c
@@ -248,13 +248,16 @@ int device_private_entry_fault(struct vm_area_struct *vma,
 EXPORT_SYMBOL(device_private_entry_fault);
 #endif /* CONFIG_DEVICE_PRIVATE */
 
-static void pgmap_radix_release(struct resource *res)
+static void pgmap_radix_release(struct resource *res, unsigned long end_pgoff)
 {
 	unsigned long pgoff, order;
 
 	mutex_lock(&pgmap_lock);
-	foreach_order_pgoff(res, order, pgoff)
+	foreach_order_pgoff(res, order, pgoff) {
+		if (pgoff >= end_pgoff)
+			break;
 		radix_tree_delete(&pgmap_radix, PHYS_PFN(res->start) + pgoff);
+	}
 	mutex_unlock(&pgmap_lock);
 
 	synchronize_rcu();
@@ -309,7 +312,7 @@ static void devm_memremap_pages_release(struct device *dev, void *data)
 	mem_hotplug_done();
 
 	untrack_pfn(NULL, PHYS_PFN(align_start), align_size);
-	pgmap_radix_release(res);
+	pgmap_radix_release(res, -1);
 	dev_WARN_ONCE(dev, pgmap->altmap && pgmap->altmap->alloc,
 			"%s: failed to free all reserved pages\n", __func__);
 }
@@ -459,7 +462,7 @@ void *devm_memremap_pages(struct device *dev, struct resource *res,
 	untrack_pfn(NULL, PHYS_PFN(align_start), align_size);
  err_pfn_remap:
  err_radix:
-	pgmap_radix_release(res);
+	pgmap_radix_release(res, pgoff);
 	devres_free(page_map);
 	return ERR_PTR(error);
 }
-- 
2.11.0