Commit 77dd66a3 authored by Jan H. Schönherr's avatar Jan H. Schönherr Committed by Dan Williams
Browse files

mm: Fix devm_memremap_pages() collision handling 



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: 9476df7d ("mm: introduce find_dev_pagemap()")
Signed-off-by: default avatarJan H. Schönherr <jschoenh@amazon.de>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 10a0cd6e

kernel/memremap.c

+7 −4
Original line number Diff line number Diff line
@@ -241,13 +241,16 @@ 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();
@@ -302,7 +305,7 @@ static void devm_memremap_pages_release(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.alloc,

		      "%s: failed to free all reserved pages\n", __func__);

}
@@ -418,7 +421,7 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap) 
	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(pgmap);

	return ERR_PTR(error);

}

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