lib/genalloc.c: make the avail variable an atomic_long_t

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.  This is only expected to be an issue on
64 bit systems.

Add the <linux/atomic.h> header to pull in atomic_long* operations.  So
that 32 bit systems continue to use atomic32_t but 64 bit systems can
use atomic64_t.

Link: http://lkml.kernel.org/r/1509033843-25667-1-git-send-email-sbates@raithlin.com
Signed-off-by: Stephen Bates <sbates@raithlin.com>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: Daniel Mentz <danielmentz@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/genalloc.h b/include/linux/genalloc.h
index 6dfec4d638df3e7b10811191aba871e421c8d724..872f930f1b06d4bbb21f1d371a1d63d306d695dd 100644 (file)
--- 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;
+       atomic_long_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 144fe6b1a03ea536893f6e35d153a895a238b67d..ca06adc4f44510d816ddc9911a1ff38f04cd497b 100644 (file)
--- 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);
+       atomic_long_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 > atomic_long_read(&chunk->avail))
                        continue;
 
                start_bit = 0;
@@ -324,7 +324,7 @@ retry:
 
                addr = chunk->start_addr + ((unsigned long)start_bit << order);
                size = nbits << order;
-               atomic_sub(size, &chunk->avail);
+               atomic_long_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);
+                       atomic_long_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 += atomic_long_read(&chunk->avail);
        rcu_read_unlock();
        return avail;
 }