On Wed, Jun 26, 2019 at 02:27:14PM +0200, Christoph Hellwig wrote: > 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 <[email protected]> > --- > include/linux/memremap.h | 4 ++ > kernel/memremap.c | 64 ++++++++++++++++++++++++------- > tools/testing/nvdimm/test/iomap.c | 58 ++++++++++++++++++++++------ > 3 files changed, 101 insertions(+), 25 deletions(-) > > diff --git a/include/linux/memremap.h b/include/linux/memremap.h > index e25685b878e9..f8a5b2a19945 100644 > --- a/include/linux/memremap.h > +++ b/include/linux/memremap.h > @@ -95,6 +95,8 @@ struct dev_pagemap_ops { > * @altmap: pre-allocated/reserved memory for vmemmap allocations > * @res: physical address range covered by @ref > * @ref: reference count that pins the devm_memremap_pages() mapping > + * @internal_ref: internal reference if @ref is not provided by the caller > + * @done: completion for @internal_ref > * @dev: host device of the mapping for debug > * @data: private data pointer for page_free() > * @type: memory type: see MEMORY_* in memory_hotplug.h > @@ -105,6 +107,8 @@ struct dev_pagemap { > struct vmem_altmap altmap; > struct resource res; > struct percpu_ref *ref; > + struct percpu_ref internal_ref; > + struct completion done; > struct device *dev; > enum memory_type type; > unsigned int flags; > diff --git a/kernel/memremap.c b/kernel/memremap.c > index eee490e7d7e1..bea6f887adad 100644 > --- a/kernel/memremap.c > +++ b/kernel/memremap.c > @@ -29,7 +29,7 @@ static void devmap_managed_enable_put(void *data) > > static int devmap_managed_enable_get(struct device *dev, struct dev_pagemap > *pgmap) > { > - if (!pgmap->ops->page_free) { > + if (!pgmap->ops || !pgmap->ops->page_free) { > WARN(1, "Missing page_free method\n"); > return -EINVAL; > } > @@ -75,6 +75,24 @@ static unsigned long pfn_next(unsigned long pfn) > #define for_each_device_pfn(pfn, map) \ > for (pfn = pfn_first(map); pfn < pfn_end(map); pfn = pfn_next(pfn)) > > +static void dev_pagemap_kill(struct dev_pagemap *pgmap) > +{ > + if (pgmap->ops && pgmap->ops->kill) > + pgmap->ops->kill(pgmap); > + else > + percpu_ref_kill(pgmap->ref); > +} > + > +static void dev_pagemap_cleanup(struct dev_pagemap *pgmap) > +{ > + if (pgmap->ops && pgmap->ops->cleanup) { > + pgmap->ops->cleanup(pgmap); > + } else { > + wait_for_completion(&pgmap->done); > + percpu_ref_exit(pgmap->ref); > + } > +} > + > static void devm_memremap_pages_release(void *data) > { > struct dev_pagemap *pgmap = data; > @@ -84,10 +102,10 @@ static void devm_memremap_pages_release(void *data) > unsigned long pfn; > int nid; > > - pgmap->ops->kill(pgmap); > + dev_pagemap_kill(pgmap); > for_each_device_pfn(pfn, pgmap) > put_page(pfn_to_page(pfn)); > - pgmap->ops->cleanup(pgmap); > + dev_pagemap_cleanup(pgmap); > > /* pages are dead and unused, undo the arch mapping */ > align_start = res->start & ~(SECTION_SIZE - 1); > @@ -114,20 +132,29 @@ static void devm_memremap_pages_release(void *data) > "%s: failed to free all reserved pages\n", __func__); > } > > +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); > +} > + > /** > * devm_memremap_pages - remap and provide memmap backing for the given > resource > * @dev: hosting device for @res > * @pgmap: pointer to a struct dev_pagemap > * > * Notes: > - * 1/ At a minimum the res, ref and type and ops members of @pgmap must be > - * initialized by the caller before passing it to this function > + * 1/ At a minimum the res and type members of @pgmap must be initialized > + * by the caller before passing it to this function > * > * 2/ The altmap field may optionally be initialized, in which case > * PGMAP_ALTMAP_VALID must be set in pgmap->flags. > * > - * 3/ pgmap->ref must be 'live' on entry and will be killed and reaped > - * at devm_memremap_pages_release() time, or if this routine fails. > + * 3/ The ref field may optionally be provided, in which pgmap->ref must be > + * 'live' on entry and will be killed and reaped at > + * devm_memremap_pages_release() time, or if this routine fails. > * > * 4/ res is expected to be a host memory range that could feasibly be > * treated as a "System RAM" range, i.e. not a device mmio range, but > @@ -175,10 +202,21 @@ void *devm_memremap_pages(struct device *dev, struct > dev_pagemap *pgmap) > break; > } > > - if (!pgmap->ref || !pgmap->ops || !pgmap->ops->kill || > - !pgmap->ops->cleanup) { > - WARN(1, "Missing reference count teardown definition\n"); > - return ERR_PTR(-EINVAL); > + 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); > + }
After this series are there any users who continue to supply their own reference object and these callbacks? As it stands: Reviewed-by: Ira Weiny <[email protected]> > } > > if (need_devmap_managed) { > @@ -296,8 +334,8 @@ void *devm_memremap_pages(struct device *dev, struct > dev_pagemap *pgmap) > err_pfn_remap: > pgmap_array_delete(res); > err_array: > - pgmap->ops->kill(pgmap); > - pgmap->ops->cleanup(pgmap); > + dev_pagemap_kill(pgmap); > + dev_pagemap_cleanup(pgmap); > return ERR_PTR(error); > } > EXPORT_SYMBOL_GPL(devm_memremap_pages); > diff --git a/tools/testing/nvdimm/test/iomap.c > b/tools/testing/nvdimm/test/iomap.c > index 82f901569e06..cd040b5abffe 100644 > --- a/tools/testing/nvdimm/test/iomap.c > +++ b/tools/testing/nvdimm/test/iomap.c > @@ -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; > - > - 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; > + if (!nfit_res) > + return devm_memremap_pages(dev, pgmap); > + > + 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); > > -- > 2.20.1 > > _______________________________________________ > Linux-nvdimm mailing list > [email protected] > https://lists.01.org/mailman/listinfo/linux-nvdimm _______________________________________________ Linux-nvdimm mailing list [email protected] https://lists.01.org/mailman/listinfo/linux-nvdimm
