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* [PATCH] dma-pool: Do not allocate pool memory from CMA
@ 2020-07-08 16:49 Nicolas Saenz Julienne
  2020-07-08 16:58 ` Christoph Hellwig
                   ` (3 more replies)
  0 siblings, 4 replies; 28+ messages in thread
From: Nicolas Saenz Julienne @ 2020-07-08 16:49 UTC (permalink / raw)
  To: Christoph Hellwig, Marek Szyprowski, Robin Murphy, David Rientjes
  Cc: iommu, linux-rpi-kernel, jeremy.linton, linux-kernel

There is no guarantee to CMA's placement, so allocating a zone specific
atomic pool from CMA might return memory from a completely different
memory zone. So stop using it.

Fixes: c84dc6e68a1d ("dma-pool: add additional coherent pools to map to gfp mask")
Reported-by: Jeremy Linton <jeremy.linton@arm.com>
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
---

An more costly alternative would be adding an option to
dma_alloc_from_contiguous() so it fails when the allocation doesn't fall
in a specific zone.

 kernel/dma/pool.c | 11 ++---------
 1 file changed, 2 insertions(+), 9 deletions(-)

diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c
index 8cfa01243ed2..4bc1c46ae6ef 100644
--- a/kernel/dma/pool.c
+++ b/kernel/dma/pool.c
@@ -6,7 +6,6 @@
 #include <linux/debugfs.h>
 #include <linux/dma-direct.h>
 #include <linux/dma-noncoherent.h>
-#include <linux/dma-contiguous.h>
 #include <linux/init.h>
 #include <linux/genalloc.h>
 #include <linux/set_memory.h>
@@ -69,12 +68,7 @@ static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size,
 
 	do {
 		pool_size = 1 << (PAGE_SHIFT + order);
-
-		if (dev_get_cma_area(NULL))
-			page = dma_alloc_from_contiguous(NULL, 1 << order,
-							 order, false);
-		else
-			page = alloc_pages(gfp, order);
+		page = alloc_pages(gfp, order);
 	} while (!page && order-- > 0);
 	if (!page)
 		goto out;
@@ -118,8 +112,7 @@ static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size,
 	dma_common_free_remap(addr, pool_size);
 #endif
 free_page: __maybe_unused
-	if (!dma_release_from_contiguous(NULL, page, 1 << order))
-		__free_pages(page, order);
+	__free_pages(page, order);
 out:
 	return ret;
 }
-- 
2.27.0

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^ permalink raw reply related	[flat|nested] 28+ messages in thread

end of thread, other threads:[~2020-07-31 10:09 UTC | newest]

Thread overview: 28+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-07-08 16:49 [PATCH] dma-pool: Do not allocate pool memory from CMA Nicolas Saenz Julienne
2020-07-08 16:58 ` Christoph Hellwig
2020-07-08 23:14 ` Jeremy Linton
2020-07-09 21:47 ` David Rientjes via iommu
2020-07-21  7:21 ` Amit Pundir
2020-07-21  8:39   ` Nicolas Saenz Julienne
2020-07-21  8:54     ` Amit Pundir
2020-07-21 11:15       ` Nicolas Saenz Julienne
2020-07-21 11:28         ` Christoph Hellwig
2020-07-21 11:37           ` Nicolas Saenz Julienne
2020-07-21 12:16             ` Amit Pundir
2020-07-21 12:15         ` Amit Pundir
2020-07-21 12:45           ` Nicolas Saenz Julienne
2020-07-21 15:22             ` Amit Pundir
2020-07-21 16:27               ` Nicolas Saenz Julienne
2020-07-23  5:14                 ` Amit Pundir
2020-07-24  9:36                   ` Nicolas Saenz Julienne
2020-07-24 11:06                     ` Amit Pundir
2020-07-24 13:41                       ` Christoph Hellwig
2020-07-24 16:19                         ` Amit Pundir
2020-07-24 16:27                           ` Christoph Hellwig
2020-07-27 17:56                         ` Nicolas Saenz Julienne
2020-07-28  9:13                           ` Christoph Hellwig
2020-07-28  9:30                             ` Nicolas Saenz Julienne
2020-07-28 10:09                               ` Christoph Hellwig
2020-07-31  1:10                                 ` Nathan Chancellor
2020-07-31  7:19                                   ` Amit Pundir
2020-07-31 10:09                                   ` Nicolas Saenz Julienne

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