Re: [PATCH] parport: fix if-statement empty body warnings

From: Randy Dunlap
Date: Thu Feb 27 2020 - 21:52:35 EST


On 2/27/20 6:32 PM, Joe Perches wrote:
> On Thu, 2020-02-27 at 18:08 -0800, Randy Dunlap wrote:
>> From: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
>>
>> When debugging via DPRINTK() is not enabled, make the DPRINTK()
>> macro be an empty do-while block.
>>
>> This fixes gcc warnings when -Wextra is set:
>>
>> ../drivers/parport/ieee1284.c:262:18: warning: suggest braces around empty body in an âifâ statement [-Wempty-body]
>> ../drivers/parport/ieee1284.c:285:17: warning: suggest braces around empty body in an âifâ statement [-Wempty-body]
>> ../drivers/parport/ieee1284.c:298:17: warning: suggest braces around empty body in an âifâ statement [-Wempty-body]
>> ../drivers/parport/ieee1284_ops.c:576:18: warning: suggest braces around empty body in an âifâ statement [-Wempty-body]
>>
>> I have verified that there is no object code change (with gcc 7.5.0).
>>
>> Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
>> Cc: Sudip Mukherjee <sudipm.mukherjee@xxxxxxxxx>
>> Cc: Sudip Mukherjee <sudip.mukherjee@xxxxxxxxxxxxxxx>
>> Cc: linux-parport@xxxxxxxxxxxxxxxxxxx
>> ---
>> drivers/parport/ieee1284.c | 2 +-
>> drivers/parport/ieee1284_ops.c | 2 +-
>> 2 files changed, 2 insertions(+), 2 deletions(-)
>>
>> --- linux-next-20200225.orig/drivers/parport/ieee1284.c
>> +++ linux-next-20200225/drivers/parport/ieee1284.c
>> @@ -34,7 +34,7 @@
>> #ifdef DEBUG
>> #define DPRINTK(stuff...) printk (stuff)
>> #else
>> -#define DPRINTK(stuff...)
>> +#define DPRINTK(stuff...) do {} while (0)
>
> It's frequently better to use noprintk

Hi Joe,

I can't find that one. Oh, it's no_printk.


> And perhaps this should just become
>
> #define DPRINTK pr_debug
>
> or perhaps a conversion of DPRINTK uses


I'm OK with any of those. If you would also fix ieee1284.c:

CC [M] drivers/parport/ieee1284.o
../drivers/parport/ieee1284.c: In function âparport_ieee1284_terminateâ:
../drivers/parport/ieee1284.c:262:18: warning: suggest braces around empty body in an âifâ statement [-Wempty-body]
port->name);
^
../drivers/parport/ieee1284.c:285:17: warning: suggest braces around empty body in an âifâ statement [-Wempty-body]
port->name);
^
../drivers/parport/ieee1284.c:298:17: warning: suggest braces around empty body in an âifâ statement [-Wempty-body]
port->name);
^

you can add my ack to the patch:
Acked-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>

Thanks.

> ---
> drivers/parport/ieee1284_ops.c | 67 +++++++++++++++---------------------------
> 1 file changed, 23 insertions(+), 44 deletions(-)
>
> diff --git a/drivers/parport/ieee1284_ops.c b/drivers/parport/ieee1284_ops.c
> index 5d41dd..b1c9f51 100644
> --- a/drivers/parport/ieee1284_ops.c
> +++ b/drivers/parport/ieee1284_ops.c
> @@ -27,12 +27,6 @@
> #undef DEBUG /* Don't want a garbled console */
> #endif
>
> -#ifdef DEBUG
> -#define DPRINTK(stuff...) printk (stuff)
> -#else
> -#define DPRINTK(stuff...)
> -#endif
> -
> /*** *
> * One-way data transfer functions. *
> * ***/
> @@ -115,7 +109,7 @@ size_t parport_ieee1284_write_compat (struct parport *port,
> if (signal_pending (current))
> break;
>
> - DPRINTK (KERN_DEBUG "%s: Timed out\n", port->name);
> + pr_debug("%s: Timed out\n", port->name);
> break;
>
> ready:
> @@ -178,9 +172,8 @@ size_t parport_ieee1284_read_nibble (struct parport *port,
> if (parport_wait_peripheral (port,
> PARPORT_STATUS_ACK, 0)) {
> /* Timeout -- no more data? */
> - DPRINTK (KERN_DEBUG
> - "%s: Nibble timeout at event 9 (%d bytes)\n",
> - port->name, i/2);
> + pr_debug("%s: Nibble timeout at event 9 (%d bytes)\n",
> + port->name, i / 2);
> parport_frob_control (port, PARPORT_CONTROL_AUTOFD, 0);
> break;
> }
> @@ -201,8 +194,7 @@ size_t parport_ieee1284_read_nibble (struct parport *port,
> PARPORT_STATUS_ACK,
> PARPORT_STATUS_ACK)) {
> /* Timeout -- no more data? */
> - DPRINTK (KERN_DEBUG
> - "%s: Nibble timeout at event 11\n",
> + pr_debug("%s: Nibble timeout at event 11\n",
> port->name);
> break;
> }
> @@ -219,9 +211,8 @@ size_t parport_ieee1284_read_nibble (struct parport *port,
> /* Read the last nibble without checking data avail. */
> if (parport_read_status (port) & PARPORT_STATUS_ERROR) {
> end_of_data:
> - DPRINTK (KERN_DEBUG
> - "%s: No more nibble data (%d bytes)\n",
> - port->name, i/2);
> + pr_debug("%s: No more nibble data (%d bytes)\n",
> + port->name, i / 2);
>
> /* Go to reverse idle phase. */
> parport_frob_control (port,
> @@ -272,8 +263,7 @@ size_t parport_ieee1284_read_byte (struct parport *port,
> /* Timeout -- no more data? */
> parport_frob_control (port, PARPORT_CONTROL_AUTOFD,
> 0);
> - DPRINTK (KERN_DEBUG "%s: Byte timeout at event 9\n",
> - port->name);
> + pr_debug("%s: Byte timeout at event 9\n", port->name);
> break;
> }
>
> @@ -288,8 +278,7 @@ size_t parport_ieee1284_read_byte (struct parport *port,
> PARPORT_STATUS_ACK,
> PARPORT_STATUS_ACK)) {
> /* Timeout -- no more data? */
> - DPRINTK (KERN_DEBUG "%s: Byte timeout at event 11\n",
> - port->name);
> + pr_debug("%s: Byte timeout at event 11\n", port->name);
> break;
> }
>
> @@ -307,8 +296,7 @@ size_t parport_ieee1284_read_byte (struct parport *port,
> /* Read the last byte without checking data avail. */
> if (parport_read_status (port) & PARPORT_STATUS_ERROR) {
> end_of_data:
> - DPRINTK (KERN_DEBUG
> - "%s: No more byte data (%zd bytes)\n",
> + pr_debug("%s: No more byte data (%zd bytes)\n",
> port->name, count);
>
> /* Go to reverse idle phase. */
> @@ -353,12 +341,10 @@ int ecp_forward_to_reverse (struct parport *port)
> PARPORT_STATUS_PAPEROUT, 0);
>
> if (!retval) {
> - DPRINTK (KERN_DEBUG "%s: ECP direction: reverse\n",
> - port->name);
> + pr_debug("%s: ECP direction: reverse\n", port->name);
> port->ieee1284.phase = IEEE1284_PH_REV_IDLE;
> } else {
> - DPRINTK (KERN_DEBUG "%s: ECP direction: failed to reverse\n",
> - port->name);
> + pr_debug("%s: ECP direction: failed to reverse\n", port->name);
> port->ieee1284.phase = IEEE1284_PH_ECP_DIR_UNKNOWN;
> }
>
> @@ -384,12 +370,10 @@ int ecp_reverse_to_forward (struct parport *port)
>
> if (!retval) {
> parport_data_forward (port);
> - DPRINTK (KERN_DEBUG "%s: ECP direction: forward\n",
> - port->name);
> + pr_debug("%s: ECP direction: forward\n", port->name);
> port->ieee1284.phase = IEEE1284_PH_FWD_IDLE;
> } else {
> - DPRINTK (KERN_DEBUG
> - "%s: ECP direction: failed to switch forward\n",
> + pr_debug("%s: ECP direction: failed to switch forward\n",
> port->name);
> port->ieee1284.phase = IEEE1284_PH_ECP_DIR_UNKNOWN;
> }
> @@ -450,7 +434,7 @@ size_t parport_ieee1284_ecp_write_data (struct parport *port,
> }
>
> /* Time for Host Transfer Recovery (page 41 of IEEE1284) */
> - DPRINTK (KERN_DEBUG "%s: ECP transfer stalled!\n", port->name);
> + pr_debug("%s: ECP transfer stalled!\n", port->name);
>
> parport_frob_control (port, PARPORT_CONTROL_INIT,
> PARPORT_CONTROL_INIT);
> @@ -466,8 +450,7 @@ size_t parport_ieee1284_ecp_write_data (struct parport *port,
> if (!(parport_read_status (port) & PARPORT_STATUS_PAPEROUT))
> break;
>
> - DPRINTK (KERN_DEBUG "%s: Host transfer recovered\n",
> - port->name);
> + pr_debug("%s: Host transfer recovered\n", port->name);
>
> if (time_after_eq (jiffies, expire)) break;
> goto try_again;
> @@ -565,23 +548,20 @@ size_t parport_ieee1284_ecp_read_data (struct parport *port,
> command or a normal data byte, don't accept it. */
> if (command) {
> if (byte & 0x80) {
> - DPRINTK (KERN_DEBUG "%s: stopping short at "
> - "channel command (%02x)\n",
> + pr_debug("%s: stopping short at channel command (%02x)\n",
> port->name, byte);
> goto out;
> }
> else if (port->ieee1284.mode != IEEE1284_MODE_ECPRLE)
> - DPRINTK (KERN_DEBUG "%s: device illegally "
> - "using RLE; accepting anyway\n",
> + pr_debug("%s: device illegally using RLE; accepting anyway\n",
> port->name);
>
> rle_count = byte + 1;
>
> /* Are we allowed to read that many bytes? */
> if (rle_count > (len - count)) {
> - DPRINTK (KERN_DEBUG "%s: leaving %d RLE bytes "
> - "for next time\n", port->name,
> - rle_count);
> + pr_debug("%s: leaving %d RLE bytes for next time\n",
> + port->name, rle_count);
> break;
> }
>
> @@ -596,7 +576,7 @@ size_t parport_ieee1284_ecp_read_data (struct parport *port,
> PARPORT_STATUS_ACK)) {
> /* It's gone wrong. Return what data we have
> to the caller. */
> - DPRINTK (KERN_DEBUG "ECP read timed out at 45\n");
> + pr_debug("ECP read timed out at 45\n");
>
> if (command)
> printk (KERN_WARNING
> @@ -620,7 +600,7 @@ size_t parport_ieee1284_ecp_read_data (struct parport *port,
> memset (buf, byte, rle_count);
> buf += rle_count;
> count += rle_count;
> - DPRINTK (KERN_DEBUG "%s: decompressed to %d bytes\n",
> + pr_debug("%s: decompressed to %d bytes\n",
> port->name, rle_count);
> } else {
> /* Normal data byte. */
> @@ -686,7 +666,7 @@ size_t parport_ieee1284_ecp_write_addr (struct parport *port,
> }
>
> /* Time for Host Transfer Recovery (page 41 of IEEE1284) */
> - DPRINTK (KERN_DEBUG "%s: ECP transfer stalled!\n", port->name);
> + pr_debug("%s: ECP transfer stalled!\n", port->name);
>
> parport_frob_control (port, PARPORT_CONTROL_INIT,
> PARPORT_CONTROL_INIT);
> @@ -702,8 +682,7 @@ size_t parport_ieee1284_ecp_write_addr (struct parport *port,
> if (!(parport_read_status (port) & PARPORT_STATUS_PAPEROUT))
> break;
>
> - DPRINTK (KERN_DEBUG "%s: Host transfer recovered\n",
> - port->name);
> + pr_debug("%s: Host transfer recovered\n", port->name);
>
> if (time_after_eq (jiffies, expire)) break;
> goto try_again;
>
>


--
~Randy
Reported-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>