Merge tag 'mfd_3.4-1' of git://git.kernel.org/pub/scm/linux/kernel/git/sameo/mfd-2.6

[firefly-linux-kernel-4.4.55.git] / fs / aio.c

diff --git a/fs/aio.c b/fs/aio.c
index 5b600cb8779e6c39f55a13aa286aa5fa041b8086..4f71627264fd9276d6acb3b94f3ee5316372a394 100644 (file)
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -13,7 +13,7 @@
 #include <linux/errno.h>
 #include <linux/time.h>
 #include <linux/aio_abi.h>
-#include <linux/module.h>
+#include <linux/export.h>
 #include <linux/syscalls.h>
 #include <linux/backing-dev.h>
 #include <linux/uio.h>
@@ -199,16 +199,7 @@ static int aio_setup_ring(struct kioctx *ctx)
 static void ctx_rcu_free(struct rcu_head *head)
 {
        struct kioctx *ctx = container_of(head, struct kioctx, rcu_head);
-       unsigned nr_events = ctx->max_reqs;
-
        kmem_cache_free(kioctx_cachep, ctx);
-
-       if (nr_events) {
-               spin_lock(&aio_nr_lock);
-               BUG_ON(aio_nr - nr_events > aio_nr);
-               aio_nr -= nr_events;
-               spin_unlock(&aio_nr_lock);
-       }
 }
 
 /* __put_ioctx
@@ -217,13 +208,19 @@ static void ctx_rcu_free(struct rcu_head *head)
  */
 static void __put_ioctx(struct kioctx *ctx)
 {
+       unsigned nr_events = ctx->max_reqs;
        BUG_ON(ctx->reqs_active);
 
-       cancel_delayed_work(&ctx->wq);
-       cancel_work_sync(&ctx->wq.work);
+       cancel_delayed_work_sync(&ctx->wq);
        aio_free_ring(ctx);
        mmdrop(ctx->mm);
        ctx->mm = NULL;
+       if (nr_events) {
+               spin_lock(&aio_nr_lock);
+               BUG_ON(aio_nr - nr_events > aio_nr);
+               aio_nr -= nr_events;
+               spin_unlock(&aio_nr_lock);
+       }
        pr_debug("__put_ioctx: freeing %p\n", ctx);
        call_rcu(&ctx->rcu_head, ctx_rcu_free);
 }
@@ -247,7 +244,7 @@ static struct kioctx *ioctx_alloc(unsigned nr_events)
 {
        struct mm_struct *mm;
        struct kioctx *ctx;
-       int did_sync = 0;
+       int err = -ENOMEM;
 
        /* Prevent overflows */
        if ((nr_events > (0x10000000U / sizeof(struct io_event))) ||
@@ -256,7 +253,7 @@ static struct kioctx *ioctx_alloc(unsigned nr_events)
                return ERR_PTR(-EINVAL);
        }
 
-       if ((unsigned long)nr_events > aio_max_nr)
+       if (!nr_events || (unsigned long)nr_events > aio_max_nr)
                return ERR_PTR(-EAGAIN);
 
        ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL);
@@ -280,25 +277,14 @@ static struct kioctx *ioctx_alloc(unsigned nr_events)
                goto out_freectx;
 
        /* limit the number of system wide aios */
-       do {
-               spin_lock_bh(&aio_nr_lock);
-               if (aio_nr + nr_events > aio_max_nr ||
-                   aio_nr + nr_events < aio_nr)
-                       ctx->max_reqs = 0;
-               else
-                       aio_nr += ctx->max_reqs;
-               spin_unlock_bh(&aio_nr_lock);
-               if (ctx->max_reqs || did_sync)
-                       break;
-
-               /* wait for rcu callbacks to have completed before giving up */
-               synchronize_rcu();
-               did_sync = 1;
-               ctx->max_reqs = nr_events;
-       } while (1);
-
-       if (ctx->max_reqs == 0)
+       spin_lock(&aio_nr_lock);
+       if (aio_nr + nr_events > aio_max_nr ||
+           aio_nr + nr_events < aio_nr) {
+               spin_unlock(&aio_nr_lock);
                goto out_cleanup;
+       }
+       aio_nr += ctx->max_reqs;
+       spin_unlock(&aio_nr_lock);
 
        /* now link into global list. */
        spin_lock(&mm->ioctx_lock);
@@ -310,16 +296,13 @@ static struct kioctx *ioctx_alloc(unsigned nr_events)
        return ctx;
 
 out_cleanup:
-       __put_ioctx(ctx);
-       return ERR_PTR(-EAGAIN);
-
+       err = -EAGAIN;
+       aio_free_ring(ctx);
 out_freectx:
        mmdrop(mm);
        kmem_cache_free(kioctx_cachep, ctx);
-       ctx = ERR_PTR(-ENOMEM);
-
-       dprintk("aio: error allocating ioctx %p\n", ctx);
-       return ctx;
+       dprintk("aio: error allocating ioctx %d\n", err);
+       return ERR_PTR(err);
 }
 
 /* aio_cancel_all
@@ -407,10 +390,6 @@ void exit_aio(struct mm_struct *mm)
                aio_cancel_all(ctx);
 
                wait_for_all_aios(ctx);
-               /*
-                * Ensure we don't leave the ctx on the aio_wq
-                */
-               cancel_work_sync(&ctx->wq.work);
 
                if (1 != atomic_read(&ctx->users))
                        printk(KERN_DEBUG
@@ -920,7 +899,7 @@ static void aio_kick_handler(struct work_struct *work)
        unuse_mm(mm);
        set_fs(oldfs);
        /*
-        * we're in a worker thread already, don't use queue_delayed_work,
+        * we're in a worker thread already; no point using non-zero delay
         */
        if (requeue)
                queue_delayed_work(aio_wq, &ctx->wq, 0);