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

[ Upstream commit 36a3d1dd4e16bcd0d2ddfb4a2ec7092f0ae0d931 ]

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>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/include/linux/genalloc.h b/include/linux/genalloc.h
index 1ccaab44abcc80541a1aebc024b62e650cb3982c..ec78cd93c0c128524329906428b70abf700a054e 100644 (file)
--- a/include/linux/genalloc.h
+++ b/include/linux/genalloc.h
@@ -31,6 +31,7 @@
 #define __GENALLOC_H__
 
 #include <linux/spinlock_types.h>
+#include <linux/atomic.h>
 
 struct device;
 struct device_node;
@@ -66,7 +67,7 @@ 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 2e65d206b01c13d3ad02a57c3d0842b89c8637bd..c627c3f19935d974bfa4963eb11e64ca02c08b39 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);
@@ -285,7 +285,7 @@ unsigned long gen_pool_alloc(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;
 
                end_bit = chunk_size(chunk) >> order;
@@ -304,7 +304,7 @@ 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();
@@ -370,7 +370,7 @@ 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;
                }
@@ -444,7 +444,7 @@ 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;
 }