aio: move sanity checks and request allocation to io_submit_one()

makes for somewhat cleaner control flow in __io_submit_one()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/aio.c b/fs/aio.c
index eee4b4cfb66fe00de7b2e9f9b8ec8822035f309d..a4cc2a1cccb7516216b23c4fe34431996616e3c3 100644 (file)
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1777,35 +1777,12 @@ 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;
-       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;
@@ -1816,17 +1793,15 @@ static int __io_submit_one(struct kioctx *ctx, const struct iocb *iocb,
                 * event using the eventfd_signal() function.
                 */
                eventfd = eventfd_ctx_fdget(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_res.obj = (u64)(unsigned long)user_iocb;
@@ -1836,58 +1811,70 @@ static int __io_submit_one(struct kioctx *ctx, const struct iocb *iocb,
 
        switch (iocb->aio_lio_opcode) {
        case IOCB_CMD_PREAD:
-               ret = aio_read(&req->rw, iocb, false, compat);
-               break;
+               return aio_read(&req->rw, iocb, false, compat);
        case IOCB_CMD_PWRITE:
-               ret = aio_write(&req->rw, iocb, false, compat);
-               break;
+               return aio_write(&req->rw, iocb, false, compat);
        case IOCB_CMD_PREADV:
-               ret = aio_read(&req->rw, iocb, true, compat);
-               break;
+               return aio_read(&req->rw, iocb, true, compat);
        case IOCB_CMD_PWRITEV:
-               ret = aio_write(&req->rw, iocb, true, compat);
-               break;
+               return aio_write(&req->rw, iocb, true, compat);
        case IOCB_CMD_FSYNC:
-               ret = aio_fsync(&req->fsync, iocb, false);
-               break;
+               return aio_fsync(&req->fsync, iocb, false);
        case IOCB_CMD_FDSYNC:
-               ret = aio_fsync(&req->fsync, iocb, true);
-               break;
+               return aio_fsync(&req->fsync, iocb, true);
        case IOCB_CMD_POLL:
-               ret = aio_poll(req, iocb);
-               break;
+               return aio_poll(req, iocb);
        default:
                pr_debug("invalid aio operation %d\n", iocb->aio_lio_opcode);
-               ret = -EINVAL;
-               break;
+               return -EINVAL;
        }
-
-       /* Done with the synchronous reference */
-       iocb_put(req);
-
-       /*
-        * 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)
-               return 0;
-
-out_put_req:
-       iocb_destroy(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);
+
+       /* Done with the synchronous reference */
+       iocb_put(req);
+
+       /*
+        * 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_destroy(req);
+               put_reqs_available(ctx, 1);
+       }
+       return err;
 }
 
 /* sys_io_submit: