Commit-ID:  94cc81f9a8f995923e35e2db936741dd62d18350
Gitweb:     http://git.kernel.org/tip/94cc81f9a8f995923e35e2db936741dd62d18350
Author:     Joerg Roedel <jroe...@suse.de>
AuthorDate: Wed, 10 Jun 2015 17:49:40 +0200
Committer:  Ingo Molnar <mi...@kernel.org>
CommitDate: Thu, 11 Jun 2015 08:28:38 +0200

swiotlb: Warn on allocation failure in swiotlb_alloc_coherent()

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 - which we'll do to improve kdump behavior.

Signed-off-by: Joerg Roedel <jroe...@suse.de>
Signed-off-by: Borislav Petkov <b...@suse.de>
Acked-by: Konrad Rzeszutek Wilk <konrad.w...@oracle.com>
Acked-by: Baoquan He <b...@redhat.com>
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: Andy Lutomirski <l...@amacapital.net>
Cc: Borislav Petkov <b...@alien8.de>
Cc: Brian Gerst <brge...@gmail.com>
Cc: Dave Young <dyo...@redhat.com>
Cc: Denys Vlasenko <dvlas...@redhat.com>
Cc: H. Peter Anvin <h...@zytor.com>
Cc: Jörg Rödel <j...@8bytes.org>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Vivek Goyal <vgo...@redhat.com>
Cc: ke...@lists.infradead.org
Link: http://lkml.kernel.org/r/1433500202-25531-2-git-send-email-j...@8bytes.org
Signed-off-by: Ingo Molnar <mi...@kernel.org>
---
 lib/swiotlb.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index 3c365ab..42e192d 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -656,7 +656,7 @@ 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);
@@ -670,7 +670,7 @@ 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;
                }
        }
 
@@ -678,6 +678,13 @@ 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);
 
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