Re: [Nouveau] [PATCH 08/22] memremap: pass a struct dev_pagemap to ->kill

[Dan Williams]

On Thu, Jun 13, 2019 at 1:12 PM Logan Gunthorpe  wrote:
>
>
>
> On 2019-06-13 3:43 a.m., Christoph Hellwig wrote:
> > Passing the actual typed structure leads to more understandable code
> > vs the actual references.
>
> Ha, ok, I originally suggested this to Dan when he introduced the
> callback[1].
>
> Reviewed-by: Logan Gunthorpe 

Reviewed-by: Dan Williams 
Reported-by: Logan Gunthorpe  :)


>
> Logan
>
> [1]
> https://lore.kernel.org/lkml/8f0cae82-130f-8a64-cfbd-fda5fd76b...@deltatee.com/T/#u
>
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[Nouveau] [PATCH 08/22] memremap: pass a struct dev_pagemap to ->kill

[Christoph Hellwig]

Passing the actual typed structure leads to more understandable code
vs the actual references.

Signed-off-by: Christoph Hellwig 
---
 drivers/dax/device.c  | 7 +++
 drivers/nvdimm/pmem.c | 6 +++---
 drivers/pci/p2pdma.c  | 6 +++---
 include/linux/memremap.h  | 2 +-
 kernel/memremap.c | 4 ++--
 mm/hmm.c  | 4 ++--
 tools/testing/nvdimm/test/iomap.c | 6 ++
 7 files changed, 16 insertions(+), 19 deletions(-)

diff --git a/drivers/dax/device.c b/drivers/dax/device.c
index 4adab774dade..e23fa1bd8c97 100644
--- a/drivers/dax/device.c
+++ b/drivers/dax/device.c
@@ -37,13 +37,12 @@ static void dev_dax_percpu_exit(void *data)
percpu_ref_exit(ref);
 }
 
-static void dev_dax_percpu_kill(struct percpu_ref *data)
+static void dev_dax_percpu_kill(struct dev_pagemap *pgmap)
 {
-   struct percpu_ref *ref = data;
-   struct dev_dax *dev_dax = ref_to_dev_dax(ref);
+   struct dev_dax *dev_dax = container_of(pgmap, struct dev_dax, pgmap);
 
dev_dbg(_dax->dev, "%s\n", __func__);
-   percpu_ref_kill(ref);
+   percpu_ref_kill(pgmap->ref);
 }
 
 static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma,
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 4efbf184ea68..b9638c6553a1 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -316,11 +316,11 @@ static void pmem_release_queue(void *q)
blk_cleanup_queue(q);
 }
 
-static void pmem_kill(struct percpu_ref *ref)
+static void pmem_kill(struct dev_pagemap *pgmap)
 {
-   struct request_queue *q;
+   struct request_queue *q =
+   container_of(pgmap->ref, struct request_queue, q_usage_counter);
 
-   q = container_of(ref, typeof(*q), q_usage_counter);
blk_freeze_queue_start(q);
 }
 
diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
index 6e76380f5b97..3bcacc9222c6 100644
--- a/drivers/pci/p2pdma.c
+++ b/drivers/pci/p2pdma.c
@@ -82,7 +82,7 @@ static void pci_p2pdma_percpu_release(struct percpu_ref *ref)
complete_all(>devmap_ref_done);
 }
 
-static void pci_p2pdma_percpu_kill(struct percpu_ref *ref)
+static void pci_p2pdma_percpu_kill(struct dev_pagemap *pgmap)
 {
/*
 * pci_p2pdma_add_resource() may be called multiple times
@@ -90,10 +90,10 @@ static void pci_p2pdma_percpu_kill(struct percpu_ref *ref)
 * times. We only want the first action to actually kill the
 * percpu_ref.
 */
-   if (percpu_ref_is_dying(ref))
+   if (percpu_ref_is_dying(pgmap->ref))
return;
 
-   percpu_ref_kill(ref);
+   percpu_ref_kill(pgmap->ref);
 }
 
 static void pci_p2pdma_release(void *data)
diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index 5f7f40875b35..96a3a6d564ad 100644
--- a/include/linux/memremap.h
+++ b/include/linux/memremap.h
@@ -74,7 +74,7 @@ struct dev_pagemap_ops {
/*
 * Transition the percpu_ref in struct dev_pagemap to the dead state.
 */
-   void (*kill)(struct percpu_ref *ref);
+   void (*kill)(struct dev_pagemap *pgmap);
 };
 
 /**
diff --git a/kernel/memremap.c b/kernel/memremap.c
index e23286ce0ec4..94b830b6eca5 100644
--- a/kernel/memremap.c
+++ b/kernel/memremap.c
@@ -92,7 +92,7 @@ static void devm_memremap_pages_release(void *data)
unsigned long pfn;
int nid;
 
-   pgmap->ops->kill(pgmap->ref);
+   pgmap->ops->kill(pgmap);
for_each_device_pfn(pfn, pgmap)
put_page(pfn_to_page(pfn));
 
@@ -266,7 +266,7 @@ void *devm_memremap_pages(struct device *dev, struct 
dev_pagemap *pgmap)
  err_pfn_remap:
pgmap_array_delete(res);
  err_array:
-   pgmap->ops->kill(pgmap->ref);
+   pgmap->ops->kill(pgmap);
return ERR_PTR(error);
 }
 EXPORT_SYMBOL_GPL(devm_memremap_pages);
diff --git a/mm/hmm.c b/mm/hmm.c
index 2501ac6045d0..c76a1b5defda 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -1325,9 +1325,9 @@ static void hmm_devmem_ref_exit(void *data)
percpu_ref_exit(ref);
 }
 
-static void hmm_devmem_ref_kill(struct percpu_ref *ref)
+static void hmm_devmem_ref_kill(struct dev_pagemap *pgmap)
 {
-   percpu_ref_kill(ref);
+   percpu_ref_kill(pgmap->ref);
 }
 
 static vm_fault_t hmm_devmem_fault(struct vm_area_struct *vma,
diff --git a/tools/testing/nvdimm/test/iomap.c 
b/tools/testing/nvdimm/test/iomap.c
index 7f5ece9b5011..ee07c4de2b35 100644
--- a/tools/testing/nvdimm/test/iomap.c
+++ b/tools/testing/nvdimm/test/iomap.c
@@ -104,11 +104,9 @@ void *__wrap_devm_memremap(struct device *dev, 
resource_size_t offset,
 }
 EXPORT_SYMBOL(__wrap_devm_memremap);
 
-static void nfit_test_kill(void *_pgmap)
+static void nfit_test_kill(void *pgmap)
 {
-   struct dev_pagemap *pgmap = _pgmap;
-
-   pgmap->ops->kill(pgmap->ref);
+   pgmap->ops->kill(pgmap);
 }
 
 void *__wrap_devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
-- 
2.20.1