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authorLinus Torvalds <torvalds@linux-foundation.org>2017-09-07 15:51:11 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-09-07 15:51:11 -0700
commit2500e287bca1beb313aa298f2d36be1257cbb483 (patch)
tree21f6233475f07776e37d7dd6bc0a60842697ed68 /fs
parentae8ac6b7dbfd67f883050421fd195c153d02f5f3 (diff)
parent2a8a98673c13cb2a61a6476153acf8344adfa992 (diff)
downloadlinux-2500e287bca1beb313aa298f2d36be1257cbb483.tar.bz2
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
Diffstat (limited to 'fs')
-rw-r--r--fs/aio.c19
1 files changed, 12 insertions, 7 deletions
diff --git a/fs/aio.c b/fs/aio.c
index dcad3a66748c..8f0127526299 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -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;
@@ -707,6 +706,12 @@ static struct kioctx *ioctx_alloc(unsigned nr_events)
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;