aio: split out iocb copy from io_submit_one()

In preparation of handing in iocbs in a different fashion as well. Also
make it clear that the iocb being passed in isn't modified, by marking
it const throughout.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/aio.c b/fs/aio.c
index 59044e5..278956d 100644 (file)
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1422,7 +1422,7 @@ static void aio_complete_rw(struct kiocb *kiocb, long res, long res2)
        aio_complete(iocb, res, res2);
 }
 
-static int aio_prep_rw(struct kiocb *req, struct iocb *iocb)
+static int aio_prep_rw(struct kiocb *req, const struct iocb *iocb)
 {
        int ret;
 
@@ -1463,7 +1463,7 @@ out_fput:
        return ret;
 }
 
-static int aio_setup_rw(int rw, struct iocb *iocb, struct iovec **iovec,
+static int aio_setup_rw(int rw, const struct iocb *iocb, struct iovec **iovec,
                bool vectored, bool compat, struct iov_iter *iter)
 {
        void __user *buf = (void __user *)(uintptr_t)iocb->aio_buf;
@@ -1502,8 +1502,8 @@ static inline void aio_rw_done(struct kiocb *req, ssize_t ret)
        }
 }
 
-static ssize_t aio_read(struct kiocb *req, struct iocb *iocb, bool vectored,
-               bool compat)
+static ssize_t aio_read(struct kiocb *req, const struct iocb *iocb,
+                       bool vectored, bool compat)
 {
        struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
        struct iov_iter iter;
@@ -1535,8 +1535,8 @@ out_fput:
        return ret;
 }
 
-static ssize_t aio_write(struct kiocb *req, struct iocb *iocb, bool vectored,
-               bool compat)
+static ssize_t aio_write(struct kiocb *req, const struct iocb *iocb,
+                        bool vectored, bool compat)
 {
        struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
        struct iov_iter iter;
@@ -1591,7 +1591,8 @@ static void aio_fsync_work(struct work_struct *work)
        aio_complete(container_of(req, struct aio_kiocb, fsync), ret, 0);
 }
 
-static int aio_fsync(struct fsync_iocb *req, struct iocb *iocb, bool datasync)
+static int aio_fsync(struct fsync_iocb *req, const struct iocb *iocb,
+                    bool datasync)
 {
        if (unlikely(iocb->aio_buf || iocb->aio_offset || iocb->aio_nbytes ||
                        iocb->aio_rw_flags))
@@ -1719,7 +1720,7 @@ aio_poll_queue_proc(struct file *file, struct wait_queue_head *head,
        add_wait_queue(head, &pt->iocb->poll.wait);
 }
 
-static ssize_t aio_poll(struct aio_kiocb *aiocb, struct iocb *iocb)
+static ssize_t aio_poll(struct aio_kiocb *aiocb, const struct iocb *iocb)
 {
        struct kioctx *ctx = aiocb->ki_ctx;
        struct poll_iocb *req = &aiocb->poll;
@@ -1791,27 +1792,23 @@ out:
        return 0;
 }
 
-static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
-                        bool compat)
+static int __io_submit_one(struct kioctx *ctx, const struct iocb *iocb,
+                          struct iocb __user *user_iocb, bool compat)
 {
        struct aio_kiocb *req;
-       struct iocb iocb;
        ssize_t ret;
 
-       if (unlikely(copy_from_user(&iocb, user_iocb, sizeof(iocb))))
-               return -EFAULT;
-
        /* enforce forwards compatibility on users */
-       if (unlikely(iocb.aio_reserved2)) {
+       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)
+           (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;
@@ -1825,14 +1822,14 @@ static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
        if (unlikely(!req))
                goto out_put_reqs_available;
 
-       if (iocb.aio_flags & IOCB_FLAG_RESFD) {
+       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_ctx_fdget((int) iocb.aio_resfd);
+               req->ki_eventfd = eventfd_ctx_fdget((int) iocb->aio_resfd);
                if (IS_ERR(req->ki_eventfd)) {
                        ret = PTR_ERR(req->ki_eventfd);
                        req->ki_eventfd = NULL;
@@ -1847,32 +1844,32 @@ static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
        }
 
        req->ki_user_iocb = user_iocb;
-       req->ki_user_data = iocb.aio_data;
+       req->ki_user_data = iocb->aio_data;
 
-       switch (iocb.aio_lio_opcode) {
+       switch (iocb->aio_lio_opcode) {
        case IOCB_CMD_PREAD:
-               ret = aio_read(&req->rw, &iocb, false, compat);
+               ret = aio_read(&req->rw, iocb, false, compat);
                break;
        case IOCB_CMD_PWRITE:
-               ret = aio_write(&req->rw, &iocb, false, compat);
+               ret = aio_write(&req->rw, iocb, false, compat);
                break;
        case IOCB_CMD_PREADV:
-               ret = aio_read(&req->rw, &iocb, true, compat);
+               ret = aio_read(&req->rw, iocb, true, compat);
                break;
        case IOCB_CMD_PWRITEV:
-               ret = aio_write(&req->rw, &iocb, true, compat);
+               ret = aio_write(&req->rw, iocb, true, compat);
                break;
        case IOCB_CMD_FSYNC:
-               ret = aio_fsync(&req->fsync, &iocb, false);
+               ret = aio_fsync(&req->fsync, iocb, false);
                break;
        case IOCB_CMD_FDSYNC:
-               ret = aio_fsync(&req->fsync, &iocb, true);
+               ret = aio_fsync(&req->fsync, iocb, true);
                break;
        case IOCB_CMD_POLL:
-               ret = aio_poll(req, &iocb);
+               ret = aio_poll(req, iocb);
                break;
        default:
-               pr_debug("invalid aio operation %d\n", iocb.aio_lio_opcode);
+               pr_debug("invalid aio operation %d\n", iocb->aio_lio_opcode);
                ret = -EINVAL;
                break;
        }
@@ -1894,6 +1891,17 @@ out_put_reqs_available:
        return ret;
 }
 
+static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
+                        bool compat)
+{
+       struct iocb iocb;
+
+       if (unlikely(copy_from_user(&iocb, user_iocb, sizeof(iocb))))
+               return -EFAULT;
+
+       return __io_submit_one(ctx, &iocb, user_iocb, compat);
+}
+
 /* sys_io_submit:
  *     Queue the nr iocbs pointed to by iocbpp for processing.  Returns
  *     the number of iocbs queued.  May return -EINVAL if the aio_context