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memremap: move dev_pagemap callbacks into a separate structure

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The dev_pagemap is a growing too many callbacks.  Move them into a
separate ops structure so that they are not duplicated for multiple
instances, and an attacker can't easily overwrite them.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
This commit is contained in:
Christoph Hellwig
2019-06-26 14:27:08 +02:00
committed by Jason Gunthorpe
parent 3ed2dcdf54
commit 1e240e8d4a
8 changed files with 65 additions and 46 deletions
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19
drivers/nvdimm/pmem.c
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@@ -303,7 +303,7 @@ static const struct attribute_group *pmem_attribute_groups[] = {
NULL,
};
static void __pmem_release_queue(struct percpu_ref *ref)
static void pmem_pagemap_cleanup(struct percpu_ref *ref)
{
struct request_queue *q;
@@ -313,10 +313,10 @@ static void __pmem_release_queue(struct percpu_ref *ref)
static void pmem_release_queue(void *ref)
{
__pmem_release_queue(ref);
pmem_pagemap_cleanup(ref);
}
static void pmem_freeze_queue(struct percpu_ref *ref)
static void pmem_pagemap_kill(struct percpu_ref *ref)
{
struct request_queue *q;
@@ -339,19 +339,24 @@ static void pmem_release_pgmap_ops(void *__pgmap)
dev_pagemap_put_ops();
}
static void fsdax_pagefree(struct page *page, void *data)
static void pmem_pagemap_page_free(struct page *page, void *data)
{
wake_up_var(&page->_refcount);
}
static const struct dev_pagemap_ops fsdax_pagemap_ops = {
.page_free = pmem_pagemap_page_free,
.kill = pmem_pagemap_kill,
.cleanup = pmem_pagemap_cleanup,
};
static int setup_pagemap_fsdax(struct device *dev, struct dev_pagemap *pgmap)
{
dev_pagemap_get_ops();
if (devm_add_action_or_reset(dev, pmem_release_pgmap_ops, pgmap))
return -ENOMEM;
pgmap->type = MEMORY_DEVICE_FS_DAX;
pgmap->page_free = fsdax_pagefree;
pgmap->ops = &fsdax_pagemap_ops;
return 0;
}
@@ -409,8 +414,6 @@ static int pmem_attach_disk(struct device *dev,
pmem->pfn_flags = PFN_DEV;
pmem->pgmap.ref = &q->q_usage_counter;
pmem->pgmap.kill = pmem_freeze_queue;
pmem->pgmap.cleanup = __pmem_release_queue;
if (is_nd_pfn(dev)) {
if (setup_pagemap_fsdax(dev, &pmem->pgmap))
return -ENOMEM;