Commit 7b29f92d authored by Jens Axboe's avatar Jens Axboe
Browse files

io_uring: cache async and regular file state for fixed files 



We have to dig quite deep to check for particularly whether or not a
file supports a fast-path nonblock attempt. For fixed files, we can do
this lookup once and cache the state instead.

This adds two new bits to track whether we support async read/write
attempt, and lines up the REQ_F_ISREG bit with those two. The file slot
re-uses the last 3 (or 2, for 32-bit) of the file pointer to cache that
state, and then we mask it in when we go and use a fixed file.

Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent d44f554e

fs/io_uring.c

+57 −13
Original line number Diff line number Diff line
@@ -690,7 +690,6 @@ enum { 
	REQ_F_CUR_POS_BIT,

	REQ_F_NOWAIT_BIT,

	REQ_F_LINK_TIMEOUT_BIT,

	REQ_F_ISREG_BIT,

	REQ_F_NEED_CLEANUP_BIT,

	REQ_F_POLLED_BIT,

	REQ_F_BUFFER_SELECTED_BIT,
@@ -698,6 +697,10 @@ enum { 
	REQ_F_LTIMEOUT_ACTIVE_BIT,

	REQ_F_COMPLETE_INLINE_BIT,

	REQ_F_REISSUE_BIT,

	/* keep async read/write and isreg together and in order */

	REQ_F_ASYNC_READ_BIT,

	REQ_F_ASYNC_WRITE_BIT,

	REQ_F_ISREG_BIT,



	/* not a real bit, just to check we're not overflowing the space */

	__REQ_F_LAST_BIT,
@@ -727,8 +730,6 @@ enum { 
	REQ_F_NOWAIT		= BIT(REQ_F_NOWAIT_BIT),

	/* has or had linked timeout */

	REQ_F_LINK_TIMEOUT	= BIT(REQ_F_LINK_TIMEOUT_BIT),

	/* regular file */

	REQ_F_ISREG		= BIT(REQ_F_ISREG_BIT),

	/* needs cleanup */

	REQ_F_NEED_CLEANUP	= BIT(REQ_F_NEED_CLEANUP_BIT),

	/* already went through poll handler */
@@ -743,6 +744,12 @@ enum { 
	REQ_F_COMPLETE_INLINE	= BIT(REQ_F_COMPLETE_INLINE_BIT),

	/* caller should reissue async */

	REQ_F_REISSUE		= BIT(REQ_F_REISSUE_BIT),

	/* supports async reads */

	REQ_F_ASYNC_READ	= BIT(REQ_F_ASYNC_READ_BIT),

	/* supports async writes */

	REQ_F_ASYNC_WRITE	= BIT(REQ_F_ASYNC_WRITE_BIT),

	/* regular file */

	REQ_F_ISREG		= BIT(REQ_F_ISREG_BIT),

};



struct async_poll {
@@ -2651,7 +2658,7 @@ static bool io_bdev_nowait(struct block_device *bdev) 
 * any file. For now, just ensure that anything potentially problematic is done

 * inline.

 */

static bool io_file_supports_async(struct file *file, int rw)

static bool __io_file_supports_async(struct file *file, int rw)

{

	umode_t mode = file_inode(file)->i_mode;
@@ -2684,6 +2691,16 @@ static bool io_file_supports_async(struct file *file, int rw) 
	return file->f_op->write_iter != NULL;

}



static bool io_file_supports_async(struct io_kiocb *req, int rw)

{

	if (rw == READ && (req->flags & REQ_F_ASYNC_READ))

		return true;

	else if (rw == WRITE && (req->flags & REQ_F_ASYNC_WRITE))

		return true;



	return __io_file_supports_async(req->file, rw);

}



static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe)

{

	struct io_ring_ctx *ctx = req->ctx;
@@ -2692,7 +2709,7 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe) 
	unsigned ioprio;

	int ret;



	if (S_ISREG(file_inode(file)->i_mode))

	if (!(req->flags & REQ_F_ISREG) && S_ISREG(file_inode(file)->i_mode))

		req->flags |= REQ_F_ISREG;



	kiocb->ki_pos = READ_ONCE(sqe->off);
@@ -3289,7 +3306,7 @@ static int io_read(struct io_kiocb *req, unsigned int issue_flags) 
		kiocb->ki_flags |= IOCB_NOWAIT;



	/* If the file doesn't support async, just async punt */

	if (force_nonblock && !io_file_supports_async(req->file, READ)) {

	if (force_nonblock && !io_file_supports_async(req, READ)) {

		ret = io_setup_async_rw(req, iovec, inline_vecs, iter, true);

		return ret ?: -EAGAIN;

	}
@@ -3394,7 +3411,7 @@ static int io_write(struct io_kiocb *req, unsigned int issue_flags) 
		kiocb->ki_flags |= IOCB_NOWAIT;



	/* If the file doesn't support async, just async punt */

	if (force_nonblock && !io_file_supports_async(req->file, WRITE))

	if (force_nonblock && !io_file_supports_async(req, WRITE))

		goto copy_iov;



	/* file path doesn't support NOWAIT for non-direct_IO */
@@ -5173,7 +5190,7 @@ static bool io_arm_poll_handler(struct io_kiocb *req) 
	else

		return false;

	/* if we can't nonblock try, then no point in arming a poll handler */

	if (!io_file_supports_async(req->file, rw))

	if (!io_file_supports_async(req, rw))

		return false;



	apoll = kmalloc(sizeof(*apoll), GFP_ATOMIC);
@@ -6182,6 +6199,15 @@ static void io_wq_submit_work(struct io_wq_work *work) 
	}

}



#define FFS_ASYNC_READ		0x1UL

#define FFS_ASYNC_WRITE		0x2UL

#ifdef CONFIG_64BIT

#define FFS_ISREG		0x4UL

#else

#define FFS_ISREG		0x0UL

#endif

#define FFS_MASK		~(FFS_ASYNC_READ|FFS_ASYNC_WRITE|FFS_ISREG)



static inline struct file **io_fixed_file_slot(struct fixed_rsrc_data *file_data,

					       unsigned i)

{
@@ -6194,7 +6220,9 @@ static inline struct file **io_fixed_file_slot(struct fixed_rsrc_data *file_data 
static inline struct file *io_file_from_index(struct io_ring_ctx *ctx,

					      int index)

{

	return *io_fixed_file_slot(ctx->file_data, index);

	struct file **file_slot = io_fixed_file_slot(ctx->file_data, index);



	return (struct file *) ((unsigned long) *file_slot & FFS_MASK);

}



static struct file *io_file_get(struct io_submit_state *state,
@@ -6204,10 +6232,16 @@ static struct file *io_file_get(struct io_submit_state *state, 
	struct file *file;



	if (fixed) {

		unsigned long file_ptr;



		if (unlikely((unsigned int)fd >= ctx->nr_user_files))

			return NULL;

		fd = array_index_nospec(fd, ctx->nr_user_files);

		file = io_file_from_index(ctx, fd);

		file_ptr = (unsigned long) *io_fixed_file_slot(ctx->file_data, fd);

		file = (struct file *) (file_ptr & FFS_MASK);

		file_ptr &= ~FFS_MASK;

		/* mask in overlapping REQ_F and FFS bits */

		req->flags |= (file_ptr << REQ_F_ASYNC_READ_BIT);

		io_set_resource_node(req);

	} else {

		trace_io_uring_file_get(ctx, fd);
@@ -7556,6 +7590,8 @@ static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg, 
		goto out_free;



	for (i = 0; i < nr_args; i++, ctx->nr_user_files++) {

		unsigned long file_ptr;



		if (copy_from_user(&fd, &fds[i], sizeof(fd))) {

			ret = -EFAULT;

			goto out_fput;
@@ -7580,7 +7616,14 @@ static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg, 
			fput(file);

			goto out_fput;

		}

		*io_fixed_file_slot(file_data, i) = file;

		file_ptr = (unsigned long) file;

		if (__io_file_supports_async(file, READ))

			file_ptr |= FFS_ASYNC_READ;

		if (__io_file_supports_async(file, WRITE))

			file_ptr |= FFS_ASYNC_WRITE;

		if (S_ISREG(file_inode(file)->i_mode))

			file_ptr |= FFS_ISREG;

		*io_fixed_file_slot(file_data, i) = (struct file *) file_ptr;

	}



	ret = io_sqe_files_scm(ctx);
@@ -7713,7 +7756,8 @@ static int __io_sqe_files_update(struct io_ring_ctx *ctx, 
		file_slot = io_fixed_file_slot(ctx->file_data, i);



		if (*file_slot) {

			err = io_queue_file_removal(data, *file_slot);

			file = (struct file *) ((unsigned long) *file_slot & FFS_MASK);

			err = io_queue_file_removal(data, file);

			if (err)

				break;

			*file_slot = NULL;
@@ -9288,7 +9332,7 @@ static void __io_uring_show_fdinfo(struct io_ring_ctx *ctx, struct seq_file *m) 
	seq_printf(m, "SqThreadCpu:\t%d\n", sq ? task_cpu(sq->thread) : -1);

	seq_printf(m, "UserFiles:\t%u\n", ctx->nr_user_files);

	for (i = 0; has_lock && i < ctx->nr_user_files; i++) {

		struct file *f = *io_fixed_file_slot(ctx->file_data, i);

		struct file *f = io_file_from_index(ctx, i);



		if (f)

			seq_printf(m, "%5u: %s\n", i, file_dentry(f)->d_iname);