[PATCH] fs: optimise kiocb_set_rw_flags()

[Pavel Begunkov]

Use a local var to collect flags in kiocb_set_rw_flags(). That spares
some memory writes and allows to replace most of the jumps with MOVEcc.

Signed-off-by: Pavel Begunkov <asml.sile...@gmail.com>
---

v2: fast exit on flags == 0 (Matthew Wilcox)

 include/linux/fs.h | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 8a00ba99284e..b7f1f1b7d691 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3282,22 +3282,28 @@ static inline int iocb_flags(struct file *file)
 
 static inline int kiocb_set_rw_flags(struct kiocb *ki, rwf_t flags)
 {
+       int kiocb_flags = 0;
+
+       if (!flags)
+               return 0;
        if (unlikely(flags & ~RWF_SUPPORTED))
                return -EOPNOTSUPP;
 
        if (flags & RWF_NOWAIT) {
                if (!(ki->ki_filp->f_mode & FMODE_NOWAIT))
                        return -EOPNOTSUPP;
-               ki->ki_flags |= IOCB_NOWAIT;
+               kiocb_flags |= IOCB_NOWAIT;
        }
        if (flags & RWF_HIPRI)
-               ki->ki_flags |= IOCB_HIPRI;
+               kiocb_flags |= IOCB_HIPRI;
        if (flags & RWF_DSYNC)
-               ki->ki_flags |= IOCB_DSYNC;
+               kiocb_flags |= IOCB_DSYNC;
        if (flags & RWF_SYNC)
-               ki->ki_flags |= (IOCB_DSYNC | IOCB_SYNC);
+               kiocb_flags |= (IOCB_DSYNC | IOCB_SYNC);
        if (flags & RWF_APPEND)
-               ki->ki_flags |= IOCB_APPEND;
+               kiocb_flags |= IOCB_APPEND;
+
+       ki->ki_flags |= kiocb_flags;
        return 0;
 }
 
-- 
2.24.0