Re: [PATCH 2/3] Staging: dgnc: Use goto for error handling

From: Giedrius StatkeviÄius
Date: Wed Mar 11 2015 - 12:38:14 EST


On 2015.03.11 16:04, Quentin Lambert wrote:
> This patch introduces goto statments for error handling
> and in cases where a lock needs to be released.
>
> A simplified version of the semantic patch that finds this problem is as
> follows: (http://coccinelle.lip6.fr)
>
> @candidates exists@
> identifier f, label;
> statement s;
> position p1, p2, p3;
> @@
>
> f@p1(...) {
> ...when any
>
> if@p2(...) {
> ...when any
> s
>
> return@p3 ...;
> }
> ...when any
> }
>
> @good1 exists@
> identifier candidates.f, candidates.label;
> statement candidates.s;
> position candidates.p1, candidates.p2;
> @@
>
> f@p1(...) {
> ...when any
>
> if(...) {
> ...when any
> s
> return ...;
> }
> ...when any
>
> if@p2(...) {...}
> ...when any
> }
>
> @depends on good1@
> identifier candidates.f, candidates.label;
> position candidates.p1, candidates.p3;
> @@
>
> f@p1(...) {
> ...when any
> * return@p3 ...;
> }
>
> Signed-off-by: Quentin Lambert <lambert.quentin@xxxxxxxxx>
> ---
> drivers/staging/dgnc/dgnc_cls.c | 19 +++++++------------
> drivers/staging/dgnc/dgnc_driver.c | 14 +++-----------
> drivers/staging/dgnc/dgnc_neo.c | 30 ++++++++++++------------------
> 3 files changed, 22 insertions(+), 41 deletions(-)
>
> diff --git a/drivers/staging/dgnc/dgnc_cls.c b/drivers/staging/dgnc/dgnc_cls.c
> index bedc522..02f19f1 100644
> --- a/drivers/staging/dgnc/dgnc_cls.c
> +++ b/drivers/staging/dgnc/dgnc_cls.c
> @@ -1029,22 +1029,16 @@ static void cls_copy_data_from_queue_to_uart(struct channel_t *ch)
> spin_lock_irqsave(&ch->ch_lock, flags);
>
> /* No data to write to the UART */
> - if (ch->ch_w_tail == ch->ch_w_head) {
> - spin_unlock_irqrestore(&ch->ch_lock, flags);
> - return;
> - }
> + if (ch->ch_w_tail == ch->ch_w_head)
> + goto exit_unlock;
>
> /* If port is "stopped", don't send any data to the UART */
> if ((ch->ch_flags & CH_FORCED_STOP) ||
> - (ch->ch_flags & CH_BREAK_SENDING)) {
> - spin_unlock_irqrestore(&ch->ch_lock, flags);
> - return;
> - }
> + (ch->ch_flags & CH_BREAK_SENDING))
> + goto exit_unlock;
>
> - if (!(ch->ch_flags & (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM))) {
> - spin_unlock_irqrestore(&ch->ch_lock, flags);
> - return;
> - }
> + if (!(ch->ch_flags & (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM)))
> + goto exit_unlock;
>
> n = 32;
>
> @@ -1094,6 +1088,7 @@ static void cls_copy_data_from_queue_to_uart(struct channel_t *ch)
> if (len_written > 0)
> ch->ch_flags &= ~(CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
>
> +exit_unlock:
> spin_unlock_irqrestore(&ch->ch_lock, flags);
> }
>
> diff --git a/drivers/staging/dgnc/dgnc_driver.c b/drivers/staging/dgnc/dgnc_driver.c
> index b7fd2bf..9387a0e 100644
> --- a/drivers/staging/dgnc/dgnc_driver.c
> +++ b/drivers/staging/dgnc/dgnc_driver.c
> @@ -572,30 +572,19 @@ static int dgnc_found_board(struct pci_dev *pdev, int id)
>
> rc = dgnc_tty_register(brd);
> if (rc < 0) {
> - dgnc_tty_uninit(brd);
> pr_err(DRVSTR ": Can't register tty devices (%d)\n", rc);
> - brd->state = BOARD_FAILED;
> - brd->dpastatus = BD_NOFEP;
> goto failed;
> }
>
> rc = dgnc_finalize_board_init(brd);
> if (rc < 0) {
> - dgnc_tty_uninit(brd);
> pr_err(DRVSTR ": Can't finalize board init (%d)\n", rc);
> - brd->state = BOARD_FAILED;
> - brd->dpastatus = BD_NOFEP;
> -
> goto failed;
> }
>
> rc = dgnc_tty_init(brd);
> if (rc < 0) {
> - dgnc_tty_uninit(brd);
> pr_err(DRVSTR ": Can't init tty devices (%d)\n", rc);
> - brd->state = BOARD_FAILED;
> - brd->dpastatus = BD_NOFEP;
> -
> goto failed;
> }
>
> @@ -629,6 +618,9 @@ static int dgnc_found_board(struct pci_dev *pdev, int id)
> return 0;
>
> failed:
> + dgnc_tty_uninit(brd);
> + brd->state = BOARD_FAILED;
> + brd->dpastatus = BD_NOFEP;
You'll probably have to remake this patch without this change because a
patch I've submitted a few days ago completely removes these and 2
other ones depend on it. It's still not in staging-testing for some reason :(

--
Thanks,
Giedrius
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