Mailing List Archive

From: Joerg Roedel <jroedel@suse.de>

Print a warning when all allocation tries have been failed
and the function is about to return NULL. This prepares for
calling the function with __GFP_NOWARN to suppress
allocation failure warnings before all fall-backs have
failed.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
lib/swiotlb.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index 4abda07..e0e9212 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -655,7 +655,7 @@ swiotlb_alloc_coherent(struct device *hwdev, size_t size,
*/
phys_addr_t paddr = map_single(hwdev, 0, size, DMA_FROM_DEVICE);
if (paddr == SWIOTLB_MAP_ERROR)
- return NULL;
+ goto err_warn;

ret = phys_to_virt(paddr);
dev_addr = phys_to_dma(hwdev, paddr);
@@ -669,7 +669,7 @@ swiotlb_alloc_coherent(struct device *hwdev, size_t size,
/* DMA_TO_DEVICE to avoid memcpy in unmap_single */
swiotlb_tbl_unmap_single(hwdev, paddr,
size, DMA_TO_DEVICE);
- return NULL;
+ goto err_warn;
}
}

@@ -677,6 +677,13 @@ swiotlb_alloc_coherent(struct device *hwdev, size_t size,
memset(ret, 0, size);

return ret;
+
+err_warn:
+ pr_warn("swiotlb: coherent allocation failed for device %s size=%zu\n",
+ dev_name(hwdev), size);
+ dump_stack();
+
+ return NULL;
}
EXPORT_SYMBOL(swiotlb_alloc_coherent);

--
1.9.1

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