Re: [PATCH] dma-debug: disable DMA_API_DEBUG for now

Joerg Roedel
2009-06-12T14:14:14Z

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On Thu, Jun 11, 2009 at 07:38:47PM +0200, Torsten Kaiser wrote:
> DMA-API: device driver tries to free DM
> A memory it has not allocated [device address=0x000000011e4c3000]
> [size=4096 bytes]

Hmm, looking again over the code I've seen that the ref
dma_debug_entries are not alway filled with all necessary information
for best-fit. Can you please try if you still get false warnings when
you apply the two patches attached instead of the one I sent yesterday?

Thanks,

Joerg

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>From 4620c534541fb4d28c0c52553274ef94a43813ab Mon Sep 17 00:00:00 2001
From: Joerg Roedel <joerg.roedel@amd.com>
Date: Thu, 11 Jun 2009 10:03:42 +0200
Subject: [PATCH 1/2] dma-debug: check for sg_call_ents in best-fit algorithm too

If we don't check for sg_call_ents the hash_bucket_find function might
still return the wrong dma_debug_entry for sg mappings.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
lib/dma-debug.c | 15 +++++++--------
1 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/lib/dma-debug.c b/lib/dma-debug.c
index ad65fc0..c71e2dd 100644
--- a/lib/dma-debug.c
+++ b/lib/dma-debug.c
@@ -262,11 +262,12 @@ static struct dma_debug_entry *hash_bucket_find(struct hash_bucket *bucket,
*/
matches += 1;
match_lvl = 0;
- entry->size == ref->size ? ++match_lvl : match_lvl;
- entry->type == ref->type ? ++match_lvl : match_lvl;
- entry->direction == ref->direction ? ++match_lvl : match_lvl;
+ entry->size == ref->size ? ++match_lvl : 0;
+ entry->type == ref->type ? ++match_lvl : 0;
+ entry->direction == ref->direction ? ++match_lvl : 0;
+ entry->sg_call_ents == ref->sg_call_ents ? ++match_lvl : 0;

- if (match_lvl == 3) {
+ if (match_lvl == 4) {
/* perfect-fit - return the result */
return entry;
} else if (match_lvl > last_lvl) {
@@ -1076,16 +1077,14 @@ void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
.dev_addr = sg_dma_address(s),
.size = sg_dma_len(s),
.direction = dir,
- .sg_call_ents = 0,
+ .sg_call_ents = nelems,
};

if (mapped_ents && i >= mapped_ents)
break;

- if (!i) {
- ref.sg_call_ents = nelems;
+ if (!i)
mapped_ents = get_nr_mapped_entries(dev, s);
- }

check_unmap(&ref);
}
--
1.6.3.1

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>From 15aad0cfd5061c6c479666234278d1473445c473 Mon Sep 17 00:00:00 2001
From: Joerg Roedel <joerg.roedel@amd.com>
Date: Fri, 12 Jun 2009 15:25:06 +0200
Subject: [PATCH 2/2] dma-debug: be more careful when building reference entries

The current code is not very careful when it builds reference
dma_debug_entries which get passed to hash_bucket_find(). But since this
function changed to a best-fit algorithm these entries have to be more
acurate. This patch adds this higher level of accuracy.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
lib/dma-debug.c | 134 +++++++++++++++++++++++++++++++++++++------------------
1 files changed, 91 insertions(+), 43 deletions(-)

diff --git a/lib/dma-debug.c b/lib/dma-debug.c
index c71e2dd..3b93129 100644
--- a/lib/dma-debug.c
+++ b/lib/dma-debug.c
@@ -874,72 +874,68 @@ static void check_for_illegal_area(struct device *dev, void *addr, u64 size)
"[addr=%p] [size=%llu]\n", addr, size);
}

-static void check_sync(struct device *dev, dma_addr_t addr,
- u64 size, u64 offset, int direction, bool to_cpu)
+static void check_sync(struct device *dev,
+ struct dma_debug_entry *ref,
+ bool to_cpu)
{
- struct dma_debug_entry ref = {
- .dev = dev,
- .dev_addr = addr,
- .size = size,
- .direction = direction,
- };
struct dma_debug_entry *entry;
struct hash_bucket *bucket;
unsigned long flags;

- bucket = get_hash_bucket(&ref, &flags);
+ bucket = get_hash_bucket(ref, &flags);

- entry = hash_bucket_find(bucket, &ref);
+ entry = hash_bucket_find(bucket, ref);

if (!entry) {
err_printk(dev, NULL, "DMA-API: device driver tries "
"to sync DMA memory it has not allocated "
"[device address=0x%016llx] [size=%llu bytes]\n",
- (unsigned long long)addr, size);
+ (unsigned long long)ref->dev_addr, ref->size);
goto out;
}

- if ((offset + size) > entry->size) {
+ if (ref->size > entry->size) {
err_printk(dev, entry, "DMA-API: device driver syncs"
" DMA memory outside allocated range "
"[device address=0x%016llx] "
- "[allocation size=%llu bytes] [sync offset=%llu] "
- "[sync size=%llu]\n", entry->dev_addr, entry->size,
- offset, size);
+ "[allocation size=%llu bytes] "
+ "[sync offset+size=%llu]\n",
+ entry->dev_addr, entry->size,
+ ref->size);
}

- if (direction != entry->direction) {
+ if (ref->direction != entry->direction) {
err_printk(dev, entry, "DMA-API: device driver syncs "
"DMA memory with different direction "
"[device address=0x%016llx] [size=%llu bytes] "
"[mapped with %s] [synced with %s]\n",
- (unsigned long long)addr, entry->size,
+ (unsigned long long)ref->dev_addr, entry->size,
dir2name[entry->direction],
- dir2name[direction]);
+ dir2name[ref->direction]);
}

if (entry->direction == DMA_BIDIRECTIONAL)
goto out;

if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
- !(direction == DMA_TO_DEVICE))
+ !(ref->direction == DMA_TO_DEVICE))
err_printk(dev, entry, "DMA-API: device driver syncs "
"device read-only DMA memory for cpu "
"[device address=0x%016llx] [size=%llu bytes] "
"[mapped with %s] [synced with %s]\n",
- (unsigned long long)addr, entry->size,
+ (unsigned long long)ref->dev_addr, entry->size,
dir2name[entry->direction],
- dir2name[direction]);
+ dir2name[ref->direction]);

if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&
- !(direction == DMA_FROM_DEVICE))
+ !(ref->direction == DMA_FROM_DEVICE))
err_printk(dev, entry, "DMA-API: device driver syncs "
"device write-only DMA memory to device "
"[device address=0x%016llx] [size=%llu bytes] "
"[mapped with %s] [synced with %s]\n",
- (unsigned long long)addr, entry->size,
+ (unsigned long long)ref->dev_addr, entry->size,
dir2name[entry->direction],
- dir2name[direction]);
+ dir2name[ref->direction]);

out:
put_hash_bucket(bucket, &flags);
@@ -1037,19 +1033,16 @@ void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
}
EXPORT_SYMBOL(debug_dma_map_sg);

-static int get_nr_mapped_entries(struct device *dev, struct scatterlist *s)
+static int get_nr_mapped_entries(struct device *dev,
+ struct dma_debug_entry *ref)
{
- struct dma_debug_entry *entry, ref;
+ struct dma_debug_entry *entry;
struct hash_bucket *bucket;
unsigned long flags;
int mapped_ents;

- ref.dev = dev;
- ref.dev_addr = sg_dma_address(s);
- ref.size = sg_dma_len(s),
-
- bucket = get_hash_bucket(&ref, &flags);
- entry = hash_bucket_find(bucket, &ref);
+ bucket = get_hash_bucket(ref, &flags);
+ entry = hash_bucket_find(bucket, ref);
mapped_ents = 0;

if (entry)
@@ -1084,7 +1077,7 @@ void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
break;

if (!i)
- mapped_ents = get_nr_mapped_entries(dev, s);
+ mapped_ents = get_nr_mapped_entries(dev, &ref);

check_unmap(&ref);
}
@@ -1139,10 +1132,19 @@ EXPORT_SYMBOL(debug_dma_free_coherent);
void debug_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
size_t size, int direction)
{
+ struct dma_debug_entry ref;
+
if (unlikely(global_disable))
return;

- check_sync(dev, dma_handle, size, 0, direction, true);
+ ref.type = dma_debug_single;
+ ref.dev = dev;
+ ref.dev_addr = dma_handle;
+ ref.size = size;
+ ref.direction = direction;
+ ref.sg_call_ents = 0;
+
+ check_sync(dev, &ref, true);
}
EXPORT_SYMBOL(debug_dma_sync_single_for_cpu);

@@ -1150,10 +1152,19 @@ void debug_dma_sync_single_for_device(struct device *dev,
dma_addr_t dma_handle, size_t size,
int direction)
{
+ struct dma_debug_entry ref;
+
if (unlikely(global_disable))
return;

- check_sync(dev, dma_handle, size, 0, direction, false);
+ ref.type = dma_debug_single;
+ ref.dev = dev;
+ ref.dev_addr = dma_handle;
+ ref.size = size;
+ ref.direction = direction;
+ ref.sg_call_ents = 0;
+
+ check_sync(dev, &ref, false);
}
EXPORT_SYMBOL(debug_dma_sync_single_for_device);

@@ -1162,10 +1173,19 @@ void debug_dma_sync_single_range_for_cpu(struct device *dev,
unsigned long offset, size_t size,
int direction)
{
+ struct dma_debug_entry ref;
+
if (unlikely(global_disable))
return;

- check_sync(dev, dma_handle, size, offset, direction, true);
+ ref.type = dma_debug_single;
+ ref.dev = dev;
+ ref.dev_addr = dma_handle;
+ ref.size = offset + size;
+ ref.direction = direction;
+ ref.sg_call_ents = 0;
+
+ check_sync(dev, &ref, true);
}
EXPORT_SYMBOL(debug_dma_sync_single_range_for_cpu);

@@ -1174,10 +1194,19 @@ void debug_dma_sync_single_range_for_device(struct device *dev,
unsigned long offset,
size_t size, int direction)
{
+ struct dma_debug_entry ref;
+
if (unlikely(global_disable))
return;

- check_sync(dev, dma_handle, size, offset, direction, false);
+ ref.type = dma_debug_single;
+ ref.dev = dev;
+ ref.dev_addr = dma_handle;
+ ref.size = offset + size;
+ ref.direction = direction;
+ ref.sg_call_ents = 0;
+
+ check_sync(dev, &ref, false);
}
EXPORT_SYMBOL(debug_dma_sync_single_range_for_device);

@@ -1191,14 +1220,24 @@ void debug_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
return;

for_each_sg(sg, s, nelems, i) {
+
+ struct dma_debug_entry ref = {
+ .type = dma_debug_sg,
+ .dev = dev,
+ .paddr = sg_phys(s),
+ .dev_addr = sg_dma_address(s),
+ .size = sg_dma_len(s),
+ .direction = direction,
+ .sg_call_ents = nelems,
+ };
+
if (!i)
- mapped_ents = get_nr_mapped_entries(dev, s);
+ mapped_ents = get_nr_mapped_entries(dev, &ref);

if (i >= mapped_ents)
break;

- check_sync(dev, sg_dma_address(s), sg_dma_len(s), 0,
- direction, true);
+ check_sync(dev, &ref, true);
}
}
EXPORT_SYMBOL(debug_dma_sync_sg_for_cpu);
@@ -1213,14 +1252,23 @@ void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
return;

for_each_sg(sg, s, nelems, i) {
+
+ struct dma_debug_entry ref = {
+ .type = dma_debug_sg,
+ .dev = dev,
+ .paddr = sg_phys(s),
+ .dev_addr = sg_dma_address(s),
+ .size = sg_dma_len(s),
+ .direction = direction,
+ .sg_call_ents = nelems,
+ };
if (!i)
- mapped_ents = get_nr_mapped_entries(dev, s);
+ mapped_ents = get_nr_mapped_entries(dev, &ref);

if (i >= mapped_ents)
break;

- check_sync(dev, sg_dma_address(s), sg_dma_len(s), 0,
- direction, false);
+ check_sync(dev, &ref, false);
}
}
EXPORT_SYMBOL(debug_dma_sync_sg_for_device);
--
1.6.3.1