To represent the size of a single allocation, dmapool currently uses
'unsigned int' in some places and 'size_t' in other places. Standardize
on 'unsigned int' to reduce overhead, but use 'size_t' when counting all
the blocks in the entire pool.
Signed-off-by: Tony Battersby <tonyb@xxxxxxxxxxxxxxx>
---
This puts an upper bound on 'size' of INT_MAX to avoid overflowing the
following comparison in pool_initialise_page():
unsigned int offset = 0;
unsigned int next = offset + pool->size;
if (unlikely((next + pool->size) > ...
'boundary' is passed in as a size_t but gets stored as an unsigned int.
'boundary' values >= 'allocation' do not have any effect, so clipping
'boundary' to 'allocation' keeps it within the range of unsigned int
without affecting anything else. A few lines above (not in the diff)
you can see that if 'boundary' is passed in as 0 then it is set to
'allocation', so it is nothing new. For reference, here is the
relevant code after being patched:
if (!boundary)
boundary = allocation;
else if ((boundary < size) || (boundary & (boundary - 1)))
return NULL;
boundary = min(boundary, allocation);
mm/dmapool.c | 19 +++++++++++--------
1 file changed, 11 insertions(+), 8 deletions(-)
diff --git a/mm/dmapool.c b/mm/dmapool.c
index 0f89de408cbe..d7b372248111 100644
--- a/mm/dmapool.c
+++ b/mm/dmapool.c
@@ -43,10 +43,10 @@
struct dma_pool { /* the pool */
struct list_head page_list;
spinlock_t lock;
- size_t size;
+ unsigned int size;
struct device *dev;
- size_t allocation;
- size_t boundary;
+ unsigned int allocation;
+ unsigned int boundary;
char name[32];
struct list_head pools;
};
@@ -80,7 +80,7 @@ static ssize_t pools_show(struct device *dev, struct device_attribute *attr, cha
mutex_lock(&pools_lock);
list_for_each_entry(pool, &dev->dma_pools, pools) {
unsigned pages = 0;
- unsigned blocks = 0;
+ size_t blocks = 0;
spin_lock_irq(&pool->lock);
list_for_each_entry(page, &pool->page_list, page_list) {
@@ -90,9 +90,10 @@ static ssize_t pools_show(struct device *dev, struct device_attribute *attr, cha
spin_unlock_irq(&pool->lock);
/* per-pool info, no real statistics yet */
- temp = scnprintf(next, size, "%-16s %4u %4zu %4zu %2u\n",
+ temp = scnprintf(next, size, "%-16s %4zu %4zu %4u %2u\n",
pool->name, blocks,
- pages * (pool->allocation / pool->size),
+ (size_t) pages *
+ (pool->allocation / pool->size),
pool->size, pages);
size -= temp;
next += temp;
@@ -139,7 +140,7 @@ struct dma_pool *dma_pool_create(const char *name, struct device *dev,
else if (align & (align - 1))
return NULL;
- if (size == 0)
+ if (size == 0 || size > INT_MAX)
return NULL;
else if (size < 4)
size = 4;
@@ -152,6 +153,8 @@ struct dma_pool *dma_pool_create(const char *name, struct device *dev,
else if ((boundary < size) || (boundary & (boundary - 1)))
return NULL;
+ boundary = min(boundary, allocation);
+
retval = kmalloc(sizeof(*retval), GFP_KERNEL);
if (!retval)
return retval;
@@ -312,7 +315,7 @@ void *dma_pool_alloc(struct dma_pool *pool, gfp_t mem_flags,
{
unsigned long flags;
struct dma_page *page;
- size_t offset;
+ unsigned int offset;
void *retval;
might_alloc(mem_flags);
--
2.25.1
