[PATCH 8/8] aio: move sanity checks and request allocation to io_submit_one()

[Al Viro]

From: Al Viro <v...@zeniv.linux.org.uk>

makes for somewhat cleaner control flow in __io_submit_one()

Signed-off-by: Al Viro <v...@zeniv.linux.org.uk>
---
 fs/aio.c | 86 +++++++++++++++++++++++++++++++---------------------------------
 1 file changed, 42 insertions(+), 44 deletions(-)

diff --git a/fs/aio.c b/fs/aio.c
index af51b1360305..6993581b77b2 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1788,36 +1788,15 @@ static int aio_poll(struct aio_kiocb *aiocb, const 
struct iocb *iocb)
 }
 
 static int __io_submit_one(struct kioctx *ctx, const struct iocb *iocb,
-                          struct iocb __user *user_iocb, bool compat)
+                          struct iocb __user *user_iocb, struct aio_kiocb *req,
+                          bool compat)
 {
-       struct aio_kiocb *req;
        struct file *file;
        int ret;
 
-       /* enforce forwards compatibility on users */
-       if (unlikely(iocb->aio_reserved2)) {
-               pr_debug("EINVAL: reserve field set\n");
-               return -EINVAL;
-       }
-
-       /* prevent overflows */
-       if (unlikely(
-           (iocb->aio_buf != (unsigned long)iocb->aio_buf) ||
-           (iocb->aio_nbytes != (size_t)iocb->aio_nbytes) ||
-           ((ssize_t)iocb->aio_nbytes < 0)
-          )) {
-               pr_debug("EINVAL: overflow check\n");
-               return -EINVAL;
-       }
-
-       req = aio_get_req(ctx);
-       if (unlikely(!req))
-               return -EAGAIN;
-
        req->ki_filp = fget(iocb->aio_fildes);
-       ret = -EBADF;
        if (unlikely(!req->ki_filp))
-               goto out_put_req;
+               return -EBADF;
 
        if (iocb->aio_flags & IOCB_FLAG_RESFD) {
                struct eventfd_ctx *eventfd;
@@ -1828,17 +1807,15 @@ static int __io_submit_one(struct kioctx *ctx, const 
struct iocb *iocb,
                 * event using the eventfd_signal() function.
                 */
                eventfd = eventfd_ctx_fdget((int) iocb->aio_resfd);
-               if (IS_ERR(eventfd)) {
-                       ret = PTR_ERR(eventfd);
-                       goto out_put_req;
-               }
+               if (IS_ERR(eventfd))
+                       return PTR_ERR(req->ki_eventfd);
+
                req->ki_eventfd = eventfd;
        }
 
-       ret = put_user(KIOCB_KEY, &user_iocb->aio_key);
-       if (unlikely(ret)) {
+       if (unlikely(put_user(KIOCB_KEY, &user_iocb->aio_key))) {
                pr_debug("EFAULT: aio_key\n");
-               goto out_put_req;
+               return -EFAULT;
        }
 
        req->ki_user_iocb = user_iocb;
@@ -1873,30 +1850,51 @@ static int __io_submit_one(struct kioctx *ctx, const 
struct iocb *iocb,
                break;
        }
        fput(file);
-
-       /*
-        * If ret is 0, we'd either done aio_complete() ourselves or have
-        * arranged for that to be done asynchronously.  Anything non-zero
-        * means that we need to destroy req ourselves.
-        */
-       if (ret)
-               goto out_put_req;
-       return 0;
-out_put_req:
-       iocb_put(req);
-       put_reqs_available(ctx, 1);
        return ret;
 }
 
 static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
                         bool compat)
 {
+       struct aio_kiocb *req;
        struct iocb iocb;
+       int err;
 
        if (unlikely(copy_from_user(&iocb, user_iocb, sizeof(iocb))))
                return -EFAULT;
 
-       return __io_submit_one(ctx, &iocb, user_iocb, compat);
+       /* enforce forwards compatibility on users */
+       if (unlikely(iocb.aio_reserved2)) {
+               pr_debug("EINVAL: reserve field set\n");
+               return -EINVAL;
+       }
+
+       /* prevent overflows */
+       if (unlikely(
+           (iocb.aio_buf != (unsigned long)iocb.aio_buf) ||
+           (iocb.aio_nbytes != (size_t)iocb.aio_nbytes) ||
+           ((ssize_t)iocb.aio_nbytes < 0)
+          )) {
+               pr_debug("EINVAL: overflow check\n");
+               return -EINVAL;
+       }
+
+       req = aio_get_req(ctx);
+       if (unlikely(!req))
+               return -EAGAIN;
+
+       err = __io_submit_one(ctx, &iocb, user_iocb, req, compat);
+
+       /*
+        * If err is 0, we'd either done aio_complete() ourselves or have
+        * arranged for that to be done asynchronously.  Anything non-zero
+        * means that we need to destroy req ourselves.
+        */
+       if (unlikely(err)) {
+               iocb_put(req);
+               put_reqs_available(ctx, 1);
+       }
+       return err;
 }
 
 /* sys_io_submit:
-- 
2.11.0