1 files changed, 26 insertions, 2 deletions

diff --git a/fs/aio.c b/fs/aio.c
index ac1c1587aa0..dbe699e9828 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -30,6 +30,7 @@
 #include <linux/highmem.h>
 #include <linux/workqueue.h>
 #include <linux/security.h>
+#include <linux/eventfd.h>
 
 #include <asm/kmap_types.h>
 #include <asm/uaccess.h>
@@ -417,6 +418,7 @@ static struct kiocb fastcall *__aio_get_req(struct kioctx *ctx)
         req->private = NULL;
         req->ki_iovec = NULL;
         INIT_LIST_HEAD(&req->ki_run_list);
+        req->ki_eventfd = ERR_PTR(-EINVAL);
 
         /* Check if the completion queue has enough free space to
          * accept an event from this io.
@@ -458,6 +460,8 @@ static inline void really_put_req(struct kioctx *ctx, struct kiocb *req)
 {
         assert_spin_locked(&ctx->ctx_lock);
 
+        if (!IS_ERR(req->ki_eventfd))
+                fput(req->ki_eventfd);
         if (req->ki_dtor)
                 req->ki_dtor(req);
         if (req->ki_iovec != &req->ki_inline_vec)
@@ -942,6 +946,14 @@ int fastcall aio_complete(struct kiocb *iocb, long res, long res2)
                 return 1;
         }
 
+        /*
+         * Check if the user asked us to deliver the result through an
+         * eventfd. The eventfd_signal() function is safe to be called
+         * from IRQ context.
+         */
+        if (!IS_ERR(iocb->ki_eventfd))
+                eventfd_signal(iocb->ki_eventfd, 1);
+
         info = &ctx->ring_info;
 
         /* add a completion event to the ring buffer.
@@ -1526,8 +1538,7 @@ int fastcall io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
         ssize_t ret;
 
         /* enforce forwards compatibility on users */
-        if (unlikely(iocb->aio_reserved1 || iocb->aio_reserved2 ||
-                     iocb->aio_reserved3)) {
+        if (unlikely(iocb->aio_reserved1 || iocb->aio_reserved2)) {
                 pr_debug("EINVAL: io_submit: reserve field set\n");
                 return -EINVAL;
         }
@@ -1551,6 +1562,19 @@ int fastcall io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
                 fput(file);
                 return -EAGAIN;
         }
+        if (iocb->aio_flags & IOCB_FLAG_RESFD) {
+                /*
+                 * If the IOCB_FLAG_RESFD flag of aio_flags is set, get an
+                 * instance of the file* now. The file descriptor must be
+                 * an eventfd() fd, and will be signaled for each completed
+                 * event using the eventfd_signal() function.
+                 */
+                req->ki_eventfd = eventfd_fget((int) iocb->aio_resfd);
+                if (unlikely(IS_ERR(req->ki_eventfd))) {
+                        ret = PTR_ERR(req->ki_eventfd);
+                        goto out_put_req;
+                }
+        }
 
         req->ki_filp = file;
         ret = put_user(req->ki_key, &user_iocb->aio_key);