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memremap: provide an optional internal refcount in struct dev_pagemap

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Provide an internal refcounting logic if no ->ref field is provided
in the pagemap passed into devm_memremap_pages so that callers don't
have to reinvent it poorly.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ira Weiny <ira.weiny@intel.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 14:27:14 +02:00
committed by Jason Gunthorpe
parent 514caf23a7
commit 24917f6b10
3 changed files with 100 additions and 24 deletions
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56
tools/testing/nvdimm/test/iomap.c
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@@ -100,26 +100,60 @@ static void nfit_test_kill(void *_pgmap)
{
struct dev_pagemap *pgmap = _pgmap;
WARN_ON(!pgmap || !pgmap->ref || !pgmap->ops || !pgmap->ops->kill ||
!pgmap->ops->cleanup);
pgmap->ops->kill(pgmap);
pgmap->ops->cleanup(pgmap);
WARN_ON(!pgmap || !pgmap->ref);
if (pgmap->ops && pgmap->ops->kill)
pgmap->ops->kill(pgmap);
else
percpu_ref_kill(pgmap->ref);
if (pgmap->ops && pgmap->ops->cleanup) {
pgmap->ops->cleanup(pgmap);
} else {
wait_for_completion(&pgmap->done);
percpu_ref_exit(pgmap->ref);
}
}
static void dev_pagemap_percpu_release(struct percpu_ref *ref)
{
struct dev_pagemap *pgmap =
container_of(ref, struct dev_pagemap, internal_ref);
complete(&pgmap->done);
}
void *__wrap_devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
{
int error;
resource_size_t offset = pgmap->res.start;
struct nfit_test_resource *nfit_res = get_nfit_res(offset);
if (nfit_res) {
int rc;
if (!nfit_res)
return devm_memremap_pages(dev, pgmap);
rc = devm_add_action_or_reset(dev, nfit_test_kill, pgmap);
if (rc)
return ERR_PTR(rc);
return nfit_res->buf + offset - nfit_res->res.start;
pgmap->dev = dev;
if (!pgmap->ref) {
if (pgmap->ops && (pgmap->ops->kill || pgmap->ops->cleanup))
return ERR_PTR(-EINVAL);
init_completion(&pgmap->done);
error = percpu_ref_init(&pgmap->internal_ref,
dev_pagemap_percpu_release, 0, GFP_KERNEL);
if (error)
return ERR_PTR(error);
pgmap->ref = &pgmap->internal_ref;
} else {
if (!pgmap->ops || !pgmap->ops->kill || !pgmap->ops->cleanup) {
WARN(1, "Missing reference count teardown definition\n");
return ERR_PTR(-EINVAL);
}
}
return devm_memremap_pages(dev, pgmap);
error = devm_add_action_or_reset(dev, nfit_test_kill, pgmap);
if (error)
return ERR_PTR(error);
return nfit_res->buf + offset - nfit_res->res.start;
}
EXPORT_SYMBOL_GPL(__wrap_devm_memremap_pages);