lkml.org 
[lkml]   [2017]   [Oct]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [PATCH v2] genalloc: Make the avail variable an atomic_long_t
----- On Oct 26, 2017, at 6:04 PM, Stephen Bates sbates@raithlin.com wrote:

> 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. 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.
>
> Changes since v1:
> Change atomic64 to atomic_long as per Mathieu
> Added a Reviewed-by tag from Logan
>
> Signed-off-by: Stephen Bates <sbates@raithlin.com>
> Reviewed-by: Logan Gunthorpe <logang@deltatee.com>

Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.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..872f930 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;
> + 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 144fe6b..ca06adc 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);
> + 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 @@ 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);
> + 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;
> }
> --
> 2.7.4

--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com

\
 
 \ /
  Last update: 2017-10-26 18:20    [W:0.046 / U:0.112 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site