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Subject[PATCH] genalloc: Make the avail variable an atomic64_t
Date
From: Stephen Bates <sbates@raithlin.com>

If the amount of resources allocated to a gen_pool exceeds 2^32 then
the avail atomic overflows and this causes problems when clients try
and borrow resources from the pool.

Add the <linux/atomic.h> header to pull in atomic64 operations on
platforms that do not support them natively.

Signed-off-by: Stephen Bates <sbates@raithlin.com>
---
include/linux/genalloc.h | 3 ++-
lib/genalloc.c | 10 +++++-----
2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/include/linux/genalloc.h b/include/linux/genalloc.h
index 6dfec4d..b327c31 100644
--- a/include/linux/genalloc.h
+++ b/include/linux/genalloc.h
@@ -32,6 +32,7 @@

#include <linux/types.h>
#include <linux/spinlock_types.h>
+#include <linux/atomic.h>

struct device;
struct device_node;
@@ -71,7 +72,7 @@ struct gen_pool {
*/
struct gen_pool_chunk {
struct list_head next_chunk; /* next chunk in pool */
- atomic_t avail;
+ atomic64_t avail;
phys_addr_t phys_addr; /* physical starting address of memory chunk */
unsigned long start_addr; /* start address of memory chunk */
unsigned long end_addr; /* end address of memory chunk (inclusive) */
diff --git a/lib/genalloc.c b/lib/genalloc.c
index 144fe6b..a97df2b 100644
--- a/lib/genalloc.c
+++ b/lib/genalloc.c
@@ -194,7 +194,7 @@ int gen_pool_add_virt(struct gen_pool *pool, unsigned long virt, phys_addr_t phy
chunk->phys_addr = phys;
chunk->start_addr = virt;
chunk->end_addr = virt + size - 1;
- atomic_set(&chunk->avail, size);
+ atomic64_set(&chunk->avail, size);

spin_lock(&pool->lock);
list_add_rcu(&chunk->next_chunk, &pool->chunks);
@@ -304,7 +304,7 @@ unsigned long gen_pool_alloc_algo(struct gen_pool *pool, size_t size,
nbits = (size + (1UL << order) - 1) >> order;
rcu_read_lock();
list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
- if (size > atomic_read(&chunk->avail))
+ if (size > atomic64_read(&chunk->avail))
continue;

start_bit = 0;
@@ -324,7 +324,7 @@ unsigned long gen_pool_alloc_algo(struct gen_pool *pool, size_t size,

addr = chunk->start_addr + ((unsigned long)start_bit << order);
size = nbits << order;
- atomic_sub(size, &chunk->avail);
+ atomic64_sub(size, &chunk->avail);
break;
}
rcu_read_unlock();
@@ -390,7 +390,7 @@ void gen_pool_free(struct gen_pool *pool, unsigned long addr, size_t size)
remain = bitmap_clear_ll(chunk->bits, start_bit, nbits);
BUG_ON(remain);
size = nbits << order;
- atomic_add(size, &chunk->avail);
+ atomic64_add(size, &chunk->avail);
rcu_read_unlock();
return;
}
@@ -464,7 +464,7 @@ size_t gen_pool_avail(struct gen_pool *pool)

rcu_read_lock();
list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk)
- avail += atomic_read(&chunk->avail);
+ avail += atomic64_read(&chunk->avail);
rcu_read_unlock();
return avail;
}
--
2.7.4
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