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io_uring: io_kiocb_update_pos() should not touch file for non -1 offset

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commit 6f83ab22ad upstream.

-1 tells use to use the current position, but we check if the file is
a stream regardless of that. Fix up io_kiocb_update_pos() to only
dip into file if we need to. This is both more efficient and also drops
12 bytes of text on aarch64 and 64 bytes on x86-64.

Fixes: b4aec40015 ("io_uring: do not recalculate ppos unnecessarily")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jens Axboe 2022-04-11 09:48:30 -06:00 committed by Greg Kroah-Hartman
parent 487a086595
commit 311b298a33
1 changed files with 10 additions and 11 deletions
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21
io_uring/io_uring.c
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@ -3014,19 +3014,18 @@ static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret)
static inline loff_t *io_kiocb_update_pos(struct io_kiocb *req)
{
struct kiocb *kiocb = &req->rw.kiocb;
bool is_stream = req->file->f_mode & FMODE_STREAM;
if (kiocb->ki_pos == -1) {
if (!is_stream) {
req->flags |= REQ_F_CUR_POS;
kiocb->ki_pos = req->file->f_pos;
return &kiocb->ki_pos;
} else {
kiocb->ki_pos = 0;
return NULL;
}
if (kiocb->ki_pos != -1)
return &kiocb->ki_pos;
if (!(req->file->f_mode & FMODE_STREAM)) {
req->flags |= REQ_F_CUR_POS;
kiocb->ki_pos = req->file->f_pos;
return &kiocb->ki_pos;
}
return is_stream ? NULL : &kiocb->ki_pos;
kiocb->ki_pos = 0;
return NULL;
}
static void kiocb_done(struct kiocb *kiocb, ssize_t ret,