Re: [PATCH] Avoid compiler warning by storing the result of rq_data_dir() in an int variable

From: Hagen Paul Pfeifer
Date: Sun Aug 02 2015 - 09:58:39 EST


* Tomer Barletz | 2015-08-02 03:36:52 [-0700]:

>With gcc 5.1 I get:
>warning: switch condition has boolean value [-Wswitch-bool]
>
>Signed-off-by: Tomer Barletz <barletz@xxxxxxxxx>
>---
> drivers/mtd/mtd_blkdevs.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
>diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c
>index 41acc50..8c3715c 100644
>--- a/drivers/mtd/mtd_blkdevs.c
>+++ b/drivers/mtd/mtd_blkdevs.c
>@@ -79,6 +79,7 @@ static int do_blktrans_request(struct mtd_blktrans_ops *tr,
> {
> unsigned long block, nsect;
> char *buf;
>+ int rq;
>
> block = blk_rq_pos(req) << 9 >> tr->blkshift;
> nsect = blk_rq_cur_bytes(req) >> tr->blkshift;
>@@ -97,7 +98,8 @@ static int do_blktrans_request(struct mtd_blktrans_ops *tr,
> if (req->cmd_flags & REQ_DISCARD)
> return tr->discard(dev, block, nsect);
>
>- switch(rq_data_dir(req)) {
>+ rq = rq_data_dir(req);
>+ switch(rq) {

Gcc warning seems over the top here, but when then the coding guideline should
be meet:

switch (rw) {
[..]

On the other hand, rq_data_dir() *could* be simplified to:

#define rq_data_dir(rq) (((rq)->cmd_flags & 1)

Or just re-code the construct into a if else construct.

if (rw == READ) {
[...]
} else {
[...]
}

The default branch is superfluous anyway here.

Hagen
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