io_uring: separate out file table handling code

Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 58 insertions, 0 deletions

diff --git a/io_uring/filetable.h b/io_uring/filetable.h
new file mode 100644
index 000000000000..fe1ec581958d
--- /dev/null
+++ b/io_uring/filetable.h
@@ -0,0 +1,58 @@
+// SPDX-License-Identifier: GPL-2.0
+#ifndef IOU_FILE_TABLE_H
+#define IOU_FILE_TABLE_H
+
+struct io_ring_ctx;
+
+/*
+ * FFS_SCM is only available on 64-bit archs, for 32-bit we just define it as 0
+ * and define IO_URING_SCM_ALL. For this case, we use SCM for all files as we
+ * can't safely always dereference the file when the task has exited and ring
+ * cleanup is done. If a file is tracked and part of SCM, then unix gc on
+ * process exit may reap it before __io_sqe_files_unregister() is run.
+ */
+#define FFS_NOWAIT		0x1UL
+#define FFS_ISREG		0x2UL
+#if defined(CONFIG_64BIT)
+#define FFS_SCM			0x4UL
+#else
+#define IO_URING_SCM_ALL
+#define FFS_SCM			0x0UL
+#endif
+#define FFS_MASK		~(FFS_NOWAIT|FFS_ISREG|FFS_SCM)
+
+struct io_fixed_file {
+	/* file * with additional FFS_* flags */
+	unsigned long file_ptr;
+};
+
+struct io_file_table {
+	struct io_fixed_file *files;
+	unsigned long *bitmap;
+	unsigned int alloc_hint;
+};
+
+bool io_alloc_file_tables(struct io_file_table *table, unsigned nr_files);
+void io_free_file_tables(struct io_file_table *table);
+int io_file_bitmap_get(struct io_ring_ctx *ctx);
+
+static inline void io_file_bitmap_clear(struct io_file_table *table, int bit)
+{
+	__clear_bit(bit, table->bitmap);
+	table->alloc_hint = bit;
+}
+
+static inline void io_file_bitmap_set(struct io_file_table *table, int bit)
+{
+	WARN_ON_ONCE(test_bit(bit, table->bitmap));
+	__set_bit(bit, table->bitmap);
+	table->alloc_hint = bit + 1;
+}
+
+static inline struct io_fixed_file *
+io_fixed_file_slot(struct io_file_table *table, unsigned i)
+{
+	return &table->files[i];
+}
+
+#endif