percpu: plumb gfp flag to pcpu_get_pages

__alloc_percpu_gfp() can be called from atomic context, so, make pcpu_get_pages use the gfp provided to the higher layer.

Quoted 2 lines · On Fri, 28 Dec 2018 17:31:47 -0800 Shakeel Butt <[email protected]> wrote:

__alloc_percpu_gfp() can be called from atomic context, so, make pcpu_get_pages use the gfp provided to the higher layer.

Does this fix any user-visible issues?

Hi Andrew,

Quoted 5 lines · Andrew Morton

Quoted 2 lines · On Fri, 28 Dec 2018 17:31:47 -0800 Shakeel Butt <[email protected]> wrote:

__alloc_percpu_gfp() can be called from atomic context, so, make pcpu_get_pages use the gfp provided to the higher layer.

Quoted 1 line

Does this fix any user-visible issues?

Sorry for not getting to this earlier. I'm currently traveling. I respoeded on the patch itself. Do you mind unqueuing? I explain in more detail on the patch, but __alloc_percpu_gfp() will never call pcpu_get_pages() when called as not GFP_KERNEL.

__alloc_percpu_gfp() can be called from atomic context, so, make pcpu_get_pages use the gfp provided to the higher layer.

Signed-off-by Shakeel Butt <[email protected]>

---
 mm/percpu-vm.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

mm/percpu-vm.c +5 -4

index d8078de912de..4f42c4c5c902 100644
@@ -21,6 +21,7 @@ static struct page *pcpu_chunk_page(struct pcpu_chunk *chunk,
 
 /**
  * pcpu_get_pages - get temp pages array
+ * @gfp: allocation flags passed to the underlying allocator
  *
  * Returns pointer to array of pointers to struct page which can be indexed
  * with pcpu_page_idx().  Note that there is only one array and accesses

@@ -29,7 +30,7 @@ static struct page *pcpu_chunk_page(struct pcpu_chunk *chunk,
  * RETURNS:
  * Pointer to temp pages array on success.
  */
-static struct page **pcpu_get_pages(void)
+static struct page **pcpu_get_pages(gfp_t gfp)
 {
 	static struct page **pages;
 	size_t pages_size = pcpu_nr_units * pcpu_unit_pages * sizeof(pages[0]);

@@ -37,7 +38,7 @@ static struct page **pcpu_get_pages(void)
 	lockdep_assert_held(&pcpu_alloc_mutex);
 
 	if (!pages)
-		pages = pcpu_mem_zalloc(pages_size, GFP_KERNEL);
+		pages = pcpu_mem_zalloc(pages_size, gfp);
 	return pages;
 }
 

@@ -278,7 +279,7 @@ static int pcpu_populate_chunk(struct pcpu_chunk *chunk,
 {
 	struct page **pages;
 
-	pages = pcpu_get_pages();
+	pages = pcpu_get_pages(gfp);
 	if (!pages)
 		return -ENOMEM;
 

@@ -316,7 +317,7 @@ static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk,
 	 * successful population attempt so the temp pages array must
 	 * be available now.
 	 */
-	pages = pcpu_get_pages();
+	pages = pcpu_get_pages(GFP_KERNEL);
 	BUG_ON(!pages);
 
 	/* unmap and free */

Signature · 1 line

2.20.1.415.g653613c723-goog