From: Tony Battersby <tonyb@cybernetics.com>
To: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Cc: iommu@lists.linux-foundation.org, kernel-team@fb.com,
Matthew Wilcox <willy@infradead.org>,
Keith Busch <kbusch@kernel.org>,
Andy Shevchenko <andy.shevchenko@gmail.com>,
Robin Murphy <robin.murphy@arm.com>,
Tony Lindgren <tony@atomide.com>
Subject: [PATCH 02/10] dmapool: cleanup integer types
Date: Tue, 31 May 2022 14:13:32 -0400 [thread overview]
Message-ID: <81004e69-d91f-9fbb-2b94-217b48a064c3@cybernetics.com> (raw)
In-Reply-To: <9b08ab7c-b80b-527d-9adf-7716b0868fbc@cybernetics.com>
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@cybernetics.com>
---
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
next prev parent reply other threads:[~2022-05-31 18:14 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-31 18:11 [PATCH 00/10] mpt3sas and dmapool scalability Tony Battersby
2022-05-31 18:12 ` [PATCH 01/10] dmapool: remove checks for dev == NULL Tony Battersby
2022-05-31 18:23 ` Robin Murphy
2022-05-31 18:13 ` Tony Battersby [this message]
2022-05-31 18:14 ` [PATCH 03/10] dmapool: fix boundary comparison Tony Battersby
2022-05-31 18:17 ` [PATCH 04/10] dmapool: improve accuracy of debug statistics Tony Battersby
2022-05-31 19:48 ` Robin Murphy
2022-05-31 19:52 ` Tony Battersby
2022-05-31 21:55 ` Robin Murphy
2022-05-31 18:18 ` [PATCH 05/10] dmapool: debug: prevent endless loop in case of corruption Tony Battersby
2022-05-31 18:20 ` [PATCH 06/10] dmapool: ignore init_on_free when DMAPOOL_DEBUG enabled Tony Battersby
2022-05-31 18:21 ` [PATCH 07/10] dmapool: speedup DMAPOOL_DEBUG with init_on_alloc Tony Battersby
2022-05-31 18:22 ` [PATCH 08/10] dmapool: cleanup dma_pool_destroy Tony Battersby
2022-05-31 19:33 ` Robin Murphy
2022-05-31 21:40 ` Keith Busch
2022-05-31 18:23 ` [PATCH 09/10] dmapool: improve scalability of dma_pool_alloc Tony Battersby
2022-05-31 18:23 ` [PATCH 10/10] dmapool: improve scalability of dma_pool_free Tony Battersby
2022-05-31 21:54 ` Keith Busch
2022-05-31 22:10 ` Tony Battersby
2022-06-01 9:44 ` Robin Murphy
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