io_uring: move remaining file table manipulation to filetable.c

Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/io_uring/filetable.c b/io_uring/filetable.c
index 560629a..e449ceb 100644
--- a/io_uring/filetable.c
+++ b/io_uring/filetable.c
@@ -4,14 +4,17 @@
 #include <linux/file.h>
 #include <linux/mm.h>
 #include <linux/slab.h>
+#include <linux/nospec.h>
 #include <linux/io_uring.h>
 
 #include <uapi/linux/io_uring.h>
 
 #include "io_uring_types.h"
 #include "io_uring.h"
+#include "rsrc.h"
+#include "filetable.h"
 
-int io_file_bitmap_get(struct io_ring_ctx *ctx)
+static int io_file_bitmap_get(struct io_ring_ctx *ctx)
 {
 	struct io_file_table *table = &ctx->file_table;
 	unsigned long nr = ctx->nr_user_files;
@@ -55,3 +58,85 @@ void io_free_file_tables(struct io_file_table *table)
 	table->files = NULL;
 	table->bitmap = NULL;
 }
+
+static int io_install_fixed_file(struct io_kiocb *req, struct file *file,
+				 unsigned int issue_flags, u32 slot_index)
+	__must_hold(&req->ctx->uring_lock)
+{
+	struct io_ring_ctx *ctx = req->ctx;
+	bool needs_switch = false;
+	struct io_fixed_file *file_slot;
+	int ret;
+
+	if (io_is_uring_fops(file))
+		return -EBADF;
+	if (!ctx->file_data)
+		return -ENXIO;
+	if (slot_index >= ctx->nr_user_files)
+		return -EINVAL;
+
+	slot_index = array_index_nospec(slot_index, ctx->nr_user_files);
+	file_slot = io_fixed_file_slot(&ctx->file_table, slot_index);
+
+	if (file_slot->file_ptr) {
+		struct file *old_file;
+
+		ret = io_rsrc_node_switch_start(ctx);
+		if (ret)
+			goto err;
+
+		old_file = (struct file *)(file_slot->file_ptr & FFS_MASK);
+		ret = io_queue_rsrc_removal(ctx->file_data, slot_index,
+					    ctx->rsrc_node, old_file);
+		if (ret)
+			goto err;
+		file_slot->file_ptr = 0;
+		io_file_bitmap_clear(&ctx->file_table, slot_index);
+		needs_switch = true;
+	}
+
+	ret = io_scm_file_account(ctx, file);
+	if (!ret) {
+		*io_get_tag_slot(ctx->file_data, slot_index) = 0;
+		io_fixed_file_set(file_slot, file);
+		io_file_bitmap_set(&ctx->file_table, slot_index);
+	}
+err:
+	if (needs_switch)
+		io_rsrc_node_switch(ctx, ctx->file_data);
+	if (ret)
+		fput(file);
+	return ret;
+}
+
+/*
+ * Note when io_fixed_fd_install() returns error value, it will ensure
+ * fput() is called correspondingly.
+ */
+int io_fixed_fd_install(struct io_kiocb *req, unsigned int issue_flags,
+			struct file *file, unsigned int file_slot)
+{
+	bool alloc_slot = file_slot == IORING_FILE_INDEX_ALLOC;
+	struct io_ring_ctx *ctx = req->ctx;
+	int ret;
+
+	io_ring_submit_lock(ctx, issue_flags);
+
+	if (alloc_slot) {
+		ret = io_file_bitmap_get(ctx);
+		if (unlikely(ret < 0))
+			goto err;
+		file_slot = ret;
+	} else {
+		file_slot--;
+	}
+
+	ret = io_install_fixed_file(req, file, issue_flags, file_slot);
+	if (!ret && alloc_slot)
+		ret = file_slot;
+err:
+	io_ring_submit_unlock(ctx, issue_flags);
+	if (unlikely(ret < 0))
+		fput(file);
+	return ret;
+}