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Subject[PATCH 1/5] aio: Move aio_nr increment to separate function
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Date
There is no functional changes, only a preparation
for next patches.

Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
---
fs/aio.c | 44 ++++++++++++++++++++++++++++++++------------
1 file changed, 32 insertions(+), 12 deletions(-)

diff --git a/fs/aio.c b/fs/aio.c
index e6de7715228c..04209c0561b2 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -694,13 +694,39 @@ static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm)
}
}

-static void aio_nr_sub(unsigned nr)
+static bool __try_to_charge_aio_nr(unsigned nr)
+{
+ if (aio_nr + nr > aio_max_nr ||
+ aio_nr + nr < aio_nr)
+ return false;
+
+ aio_nr += nr;
+ return true;
+}
+
+static void __uncharge_aio_nr(unsigned nr)
{
- spin_lock(&aio_nr_lock);
if (WARN_ON(aio_nr - nr > aio_nr))
aio_nr = 0;
else
aio_nr -= nr;
+}
+
+static bool try_to_charge_aio_nr(unsigned nr)
+{
+ bool ret;
+
+ spin_lock(&aio_nr_lock);
+ ret = __try_to_charge_aio_nr(nr);
+ spin_unlock(&aio_nr_lock);
+
+ return ret;
+}
+
+static void uncharge_aio_nr(unsigned nr)
+{
+ spin_lock(&aio_nr_lock);
+ __uncharge_aio_nr(nr);
spin_unlock(&aio_nr_lock);
}

@@ -776,15 +802,9 @@ static struct kioctx *ioctx_alloc(unsigned nr_events)
ctx->req_batch = 1;

/* limit the number of system wide aios */
- spin_lock(&aio_nr_lock);
- if (aio_nr + ctx->max_reqs > aio_max_nr ||
- aio_nr + ctx->max_reqs < aio_nr) {
- spin_unlock(&aio_nr_lock);
- err = -EAGAIN;
+ err = -EAGAIN;
+ if (!try_to_charge_aio_nr(ctx->max_reqs))
goto err_ctx;
- }
- aio_nr += ctx->max_reqs;
- spin_unlock(&aio_nr_lock);

percpu_ref_get(&ctx->users); /* io_setup() will drop this ref */
percpu_ref_get(&ctx->reqs); /* free_ioctx_users() will drop this */
@@ -801,7 +821,7 @@ static struct kioctx *ioctx_alloc(unsigned nr_events)
return ctx;

err_cleanup:
- aio_nr_sub(ctx->max_reqs);
+ uncharge_aio_nr(ctx->max_reqs);
err_ctx:
atomic_set(&ctx->dead, 1);
if (ctx->mmap_size)
@@ -848,7 +868,7 @@ static int kill_ioctx(struct mm_struct *mm, struct kioctx *ctx,
* -EAGAIN with no ioctxs actually in use (as far as userspace
* could tell).
*/
- aio_nr_sub(ctx->max_reqs);
+ uncharge_aio_nr(ctx->max_reqs);

if (ctx->mmap_size)
vm_munmap(ctx->mmap_base, ctx->mmap_size);
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