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Merge git://git.kvack.org/~bcrl/aio-next 

Pull aio fix from Ben LaHaise:
 "Improve aio-nr counting on large SMP systems.

  It has been in linux-next for quite some time"

* git://git.kvack.org/~bcrl/aio-next:
  fs: aio: fix the increment of aio-nr and counting against aio-max-nr
This commit is contained in:
Linus Torvalds 2017-09-07 15:51:11 -07:00
parent ae8ac6b7db 2a8a98673c
commit 2500e287bc
1 changed files with 12 additions and 7 deletions
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19
fs/aio.c
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@ -441,10 +441,9 @@ static const struct address_space_operations aio_ctx_aops = {
#endif
};
static int aio_setup_ring(struct kioctx *ctx)
static int aio_setup_ring(struct kioctx *ctx, unsigned int nr_events)
{
struct aio_ring *ring;
unsigned nr_events = ctx->max_reqs;
struct mm_struct *mm = current->mm;
unsigned long size, unused;
int nr_pages;
@ -706,6 +705,12 @@ static struct kioctx *ioctx_alloc(unsigned nr_events)
struct kioctx *ctx;
int err = -ENOMEM;
/*
* Store the original nr_events -- what userspace passed to io_setup(),
* for counting against the global limit -- before it changes.
*/
unsigned int max_reqs = nr_events;
/*
* We keep track of the number of available ringbuffer slots, to prevent
* overflow (reqs_available), and we also use percpu counters for this.
@ -724,14 +729,14 @@ static struct kioctx *ioctx_alloc(unsigned nr_events)
return ERR_PTR(-EINVAL);
}
if (!nr_events || (unsigned long)nr_events > (aio_max_nr * 2UL))
if (!nr_events || (unsigned long)max_reqs > aio_max_nr)
return ERR_PTR(-EAGAIN);
ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL);
if (!ctx)
return ERR_PTR(-ENOMEM);
ctx->max_reqs = nr_events;
ctx->max_reqs = max_reqs;
spin_lock_init(&ctx->ctx_lock);
spin_lock_init(&ctx->completion_lock);
@ -753,7 +758,7 @@ static struct kioctx *ioctx_alloc(unsigned nr_events)
if (!ctx->cpu)
goto err;
err = aio_setup_ring(ctx);
err = aio_setup_ring(ctx, nr_events);
if (err < 0)
goto err;
@ -764,8 +769,8 @@ static struct kioctx *ioctx_alloc(unsigned nr_events)
/* limit the number of system wide aios */
spin_lock(&aio_nr_lock);
if (aio_nr + nr_events > (aio_max_nr * 2UL) ||
aio_nr + nr_events < aio_nr) {
if (aio_nr + ctx->max_reqs > aio_max_nr ||
aio_nr + ctx->max_reqs < aio_nr) {
spin_unlock(&aio_nr_lock);
err = -EAGAIN;
goto err_ctx;