Commit 36a3d1dd authored by Stephen Bates's avatar Stephen Bates Committed by Linus Torvalds
Browse files

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: default avatarStephen Bates <sbates@raithlin.com>
Reviewed-by: default avatarLogan Gunthorpe <logang@deltatee.com>
Reviewed-by: default avatarMathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: default avatarDaniel 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e813a614

include/linux/genalloc.h

+2 −1
Original line number Diff line number Diff line
@@ -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) */

lib/genalloc.c

+5 −5
Original line number Diff line number Diff line
@@ -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;

}

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