Messages in this thread | | | Subject | Re: [PATCH] lib/dma-debug.c: fix __hash_bucket_find | From | Shuah Khan <> | Date | Thu, 18 Oct 2012 11:20:54 -0600 |
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On Thu, 2012-10-18 at 23:53 +0800, Ming Lei wrote: > Hi, > > Below v1 should be more efficient and simper, sorry for the noise. > > > Thanks, > -- > Ming Lei > > -- > From d275d195794ff80e018145f2fae714b35ddc49e2 Mon Sep 17 00:00:00 2001 > From: Ming Lei <ming.lei@canonical.com> > Date: Thu, 18 Oct 2012 23:30:57 +0800 > Subject: [PATCH v1] lib/dma-debug.c: fix __hash_bucket_find > > If there is only one match, the unique matched entry should be returned. > > Without the fix, the commit f62566214fe31c9f9b3218a42f1b19e6a9e6844a > > dma-debug: new interfaces to debug dma mapping errors > > can't work reliably because only device and dma_addr are passed to > dma_mapping_error(). > > Cc: Joerg Roedel <joerg.roedel@amd.com> > Cc: Shuah Khan <shuah.khan@hp.com> > Cc: Paul Gortmaker <paul.gortmaker@windriver.com> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Jakub Kicinski <kubakici@wp.pl> > Signed-off-by: Ming Lei <ming.lei@canonical.com> > --- > lib/dma-debug.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/lib/dma-debug.c b/lib/dma-debug.c > index 94aa94e..59f4a1a 100644 > --- a/lib/dma-debug.c > +++ b/lib/dma-debug.c > @@ -277,7 +277,7 @@ static struct dma_debug_entry > *__hash_bucket_find(struct hash_bucket *bucket, > match_fn match) > { > struct dma_debug_entry *entry, *ret = NULL; > - int matches = 0, match_lvl, last_lvl = 0; > + int matches = 0, match_lvl, last_lvl = -1; > > list_for_each_entry(entry, &bucket->list, list) { > if (!match(ref, entry)) > @@ -306,7 +306,7 @@ static struct dma_debug_entry > *__hash_bucket_find(struct hash_bucket *bucket, > } else if (match_lvl > last_lvl) { > /* > * We found an entry that fits better then the > - * previous one > + * previous one or it is the 1st match. > */ > last_lvl = match_lvl; > ret = entry;
Thanks for finding and fixing the problem. This fixes the problem Fengguang Wu reported: adding him to the thread.
https://lkml.org/lkml/2012/10/14/233
I have a reliable test case and test system that reproduces the problem. Re-tested it with and without patch and didn't see the warning with your patch.
That said, this patch is malformed and didn't apply cleanly. You have my
Tested-by: Shuah Khan <shuah.khan@hp.com>
Thanks, -- Shuah
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