Commit c97d8a0f authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

io_uring: avoid touching inode in rw prep 



If we use fixed files, we can be sure (almost) that REQ_F_ISREG is set.
However, for non-reg files io_prep_rw() still will look into inode to
double check, and that's expensive and can be avoided.

The only caveat is that it only currently works with 64+ bit
architectures, see FFS_ISREG, so we should consider that.

Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/0a62780c491ca2522cd52db4ae3f16e03aafed0f.1628471125.git.asml.silence@gmail.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent b191e2df

fs/io_uring.c

+15 −10
Original line number Diff line number Diff line
@@ -1231,6 +1231,20 @@ static bool req_need_defer(struct io_kiocb *req, u32 seq) 
	return false;

}



#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 bool io_req_ffs_set(struct io_kiocb *req)

{

	return IS_ENABLED(CONFIG_64BIT) && (req->flags & REQ_F_FIXED_FILE);

}



static void io_req_track_inflight(struct io_kiocb *req)

{

	if (!(req->flags & REQ_F_INFLIGHT)) {
@@ -2682,7 +2696,7 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe) 
	unsigned ioprio;

	int ret;



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

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

		req->flags |= REQ_F_ISREG;



	kiocb->ki_pos = READ_ONCE(sqe->off);
@@ -6319,15 +6333,6 @@ 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 io_fixed_file *io_fixed_file_slot(struct io_file_table *table,

						       unsigned i)

{