-/*
- * NB: Return the value of the first error return code. Subsequent
- * errors after the first one are ignored.
- */
-/*
- * For each wsize'd chunk of the user's buffer, dispatch an NFS WRITE
- * operation. If nfs_writedata_alloc() or get_user_pages() fails,
- * bail and stop sending more writes. Write length accounting is
- * handled automatically by nfs_direct_write_result(). Otherwise, if
- * no requests have been sent, just return an error.
- */
-static ssize_t nfs_direct_write_schedule_segment(struct nfs_pageio_descriptor *desc,
- const struct iovec *iov,
- loff_t pos, bool uio)
-{
- struct nfs_direct_req *dreq = desc->pg_dreq;
- struct nfs_open_context *ctx = dreq->ctx;
- struct inode *inode = ctx->dentry->d_inode;
- unsigned long user_addr = (unsigned long)iov->iov_base;
- size_t count = iov->iov_len;
- size_t wsize = NFS_SERVER(inode)->wsize;
- unsigned int pgbase;
- int result;
- ssize_t started = 0;
- struct page **pagevec = NULL;
- unsigned int npages;
-
- do {
- size_t bytes;
- int i;
-
- pgbase = user_addr & ~PAGE_MASK;
- bytes = min(max_t(size_t, wsize, PAGE_SIZE), count);
-
- result = -ENOMEM;
- npages = nfs_page_array_len(pgbase, bytes);
- if (!pagevec)
- pagevec = kmalloc(npages * sizeof(struct page *), GFP_KERNEL);
- if (!pagevec)
- break;
-
- if (uio) {
- down_read(¤t->mm->mmap_sem);
- result = get_user_pages(current, current->mm, user_addr,
- npages, 0, 0, pagevec, NULL);
- up_read(¤t->mm->mmap_sem);
- if (result < 0)
- break;
- } else {
- WARN_ON(npages != 1);
- result = get_kernel_page(user_addr, 0, pagevec);
- if (WARN_ON(result != 1))
- break;
- }
-
- if ((unsigned)result < npages) {
- bytes = result * PAGE_SIZE;
- if (bytes <= pgbase) {
- nfs_direct_release_pages(pagevec, result);
- break;
- }
- bytes -= pgbase;
- npages = result;
- }
-
- for (i = 0; i < npages; i++) {
- struct nfs_page *req;
- unsigned int req_len = min_t(size_t, bytes, PAGE_SIZE - pgbase);
-
- req = nfs_create_request(dreq->ctx, pagevec[i], NULL,
- pgbase, req_len);
- if (IS_ERR(req)) {
- result = PTR_ERR(req);
- break;
- }
- nfs_lock_request(req);
- req->wb_index = pos >> PAGE_SHIFT;
- req->wb_offset = pos & ~PAGE_MASK;
- if (!nfs_pageio_add_request(desc, req)) {
- result = desc->pg_error;
- nfs_unlock_and_release_request(req);
- break;
- }
- pgbase = 0;
- bytes -= req_len;
- started += req_len;
- user_addr += req_len;
- pos += req_len;
- count -= req_len;
- dreq->bytes_left -= req_len;
- }
- /* The nfs_page now hold references to these pages */
- nfs_direct_release_pages(pagevec, npages);
- } while (count != 0 && result >= 0);
-
- kfree(pagevec);
-
- if (started)
- return started;
- return result < 0 ? (ssize_t) result : -EFAULT;
-}
-