| Message ID | 20190123123442.5256-1-yuehaibing@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [-next] usb: ftdi-elan: Fix if == else warnings in ftdi_elan_respond_engine | expand |
On Wed, Jan 23, 2019 at 08:34:42PM +0800, YueHaibing wrote: > ./drivers/usb/misc/ftdi-elan.c:972:10-12: WARNING: possible condition with no effect (if == else) > ./drivers/usb/misc/ftdi-elan.c:983:9-11: WARNING: possible condition with no effect (if == else) > ./drivers/usb/misc/ftdi-elan.c:2052:11-13: WARNING: possible condition with no effect (if == else) > > Signed-off-by: YueHaibing <yuehaibing@huawei.com> You can not just provide the output of a tool as a changelog text, sorry. Please explain what those lines mean, and why you are making the change that you are. > --- > drivers/usb/misc/ftdi-elan.c | 26 -------------------------- > 1 file changed, 26 deletions(-) > > diff --git a/drivers/usb/misc/ftdi-elan.c b/drivers/usb/misc/ftdi-elan.c > index 76c718a..257efac 100644 > --- a/drivers/usb/misc/ftdi-elan.c > +++ b/drivers/usb/misc/ftdi-elan.c > @@ -915,7 +915,6 @@ static int ftdi_elan_respond_engine(struct usb_ftdi *ftdi) > int bytes_read = 0; > int retry_on_empty = 1; > int retry_on_timeout = 3; > - int empty_packets = 0; > read:{ > int packet_bytes = 0; > int retval = usb_bulk_msg(ftdi->udev, > @@ -960,31 +959,6 @@ read:{ > dev_err(&ftdi->udev->dev, "error = %d with packet_bytes = %d with total %d bytes%s\n", > retval, packet_bytes, bytes_read, diag); > return retval; > - } else if (packet_bytes == 2) { > - unsigned char s0 = ftdi->bulk_in_buffer[0]; > - unsigned char s1 = ftdi->bulk_in_buffer[1]; > - empty_packets += 1; > - if (s0 == 0x31 && s1 == 0x60) { > - if (retry_on_empty-- > 0) { > - goto more; > - } else > - return 0; > - } else if (s0 == 0x31 && s1 == 0x00) { > - if (retry_on_empty-- > 0) { > - goto more; > - } else > - return 0; > - } else { > - if (retry_on_empty-- > 0) { > - goto more; > - } else > - return 0; > - } > - } else if (packet_bytes == 1) { > - if (retry_on_empty-- > 0) { > - goto more; > - } else > - return 0; Are you _sure_ that these lines are not needed and that the compiler is not really seeing them? As it doesn't look that way to me, what am I missing? thanks, greg k-h
On 2019/1/23 20:43, Greg KH wrote: > On Wed, Jan 23, 2019 at 08:34:42PM +0800, YueHaibing wrote: >> ./drivers/usb/misc/ftdi-elan.c:972:10-12: WARNING: possible condition with no effect (if == else) >> ./drivers/usb/misc/ftdi-elan.c:983:9-11: WARNING: possible condition with no effect (if == else) >> ./drivers/usb/misc/ftdi-elan.c:2052:11-13: WARNING: possible condition with no effect (if == else) >> >> Signed-off-by: YueHaibing <yuehaibing@huawei.com> > > You can not just provide the output of a tool as a changelog text, > sorry. > > Please explain what those lines mean, and why you are making the change > that you are. ok, will do that. > >> --- >> drivers/usb/misc/ftdi-elan.c | 26 -------------------------- >> 1 file changed, 26 deletions(-) >> >> diff --git a/drivers/usb/misc/ftdi-elan.c b/drivers/usb/misc/ftdi-elan.c >> index 76c718a..257efac 100644 >> --- a/drivers/usb/misc/ftdi-elan.c >> +++ b/drivers/usb/misc/ftdi-elan.c >> @@ -915,7 +915,6 @@ static int ftdi_elan_respond_engine(struct usb_ftdi *ftdi) >> int bytes_read = 0; >> int retry_on_empty = 1; >> int retry_on_timeout = 3; >> - int empty_packets = 0; >> read:{ >> int packet_bytes = 0; >> int retval = usb_bulk_msg(ftdi->udev, >> @@ -960,31 +959,6 @@ read:{ >> dev_err(&ftdi->udev->dev, "error = %d with packet_bytes = %d with total %d bytes%s\n", >> retval, packet_bytes, bytes_read, diag); >> return retval; >> - } else if (packet_bytes == 2) { >> - unsigned char s0 = ftdi->bulk_in_buffer[0]; >> - unsigned char s1 = ftdi->bulk_in_buffer[1]; >> - empty_packets += 1; >> - if (s0 == 0x31 && s1 == 0x60) { >> - if (retry_on_empty-- > 0) { >> - goto more; >> - } else >> - return 0; >> - } else if (s0 == 0x31 && s1 == 0x00) { >> - if (retry_on_empty-- > 0) { >> - goto more; >> - } else >> - return 0; >> - } else { >> - if (retry_on_empty-- > 0) { >> - goto more; >> - } else >> - return 0; >> - } >> - } else if (packet_bytes == 1) { >> - if (retry_on_empty-- > 0) { >> - goto more; >> - } else >> - return 0; > > Are you _sure_ that these lines are not needed and that the compiler is > not really seeing them? As it doesn't look that way to me, what am I > missing? I checked and make sure that All these if/else if branch just do the same thing: if (retry_on_empty-- > 0) { goto more; } else return 0; so it can be merged into the last else branch. Also the variable 'empty_packets' doesn't use in any place, except for self increment > > thanks, > > greg k-h > > . >
On Wed, Jan 23, 2019 at 09:17:38PM +0800, YueHaibing wrote: > On 2019/1/23 20:43, Greg KH wrote: > > On Wed, Jan 23, 2019 at 08:34:42PM +0800, YueHaibing wrote: > >> ./drivers/usb/misc/ftdi-elan.c:972:10-12: WARNING: possible condition with no effect (if == else) > >> ./drivers/usb/misc/ftdi-elan.c:983:9-11: WARNING: possible condition with no effect (if == else) > >> ./drivers/usb/misc/ftdi-elan.c:2052:11-13: WARNING: possible condition with no effect (if == else) > >> > >> Signed-off-by: YueHaibing <yuehaibing@huawei.com> > > > > You can not just provide the output of a tool as a changelog text, > > sorry. > > > > Please explain what those lines mean, and why you are making the change > > that you are. > > ok, will do that. > > > > >> --- > >> drivers/usb/misc/ftdi-elan.c | 26 -------------------------- > >> 1 file changed, 26 deletions(-) > >> > >> diff --git a/drivers/usb/misc/ftdi-elan.c b/drivers/usb/misc/ftdi-elan.c > >> index 76c718a..257efac 100644 > >> --- a/drivers/usb/misc/ftdi-elan.c > >> +++ b/drivers/usb/misc/ftdi-elan.c > >> @@ -915,7 +915,6 @@ static int ftdi_elan_respond_engine(struct usb_ftdi *ftdi) > >> int bytes_read = 0; > >> int retry_on_empty = 1; > >> int retry_on_timeout = 3; > >> - int empty_packets = 0; > >> read:{ > >> int packet_bytes = 0; > >> int retval = usb_bulk_msg(ftdi->udev, > >> @@ -960,31 +959,6 @@ read:{ > >> dev_err(&ftdi->udev->dev, "error = %d with packet_bytes = %d with total %d bytes%s\n", > >> retval, packet_bytes, bytes_read, diag); > >> return retval; > >> - } else if (packet_bytes == 2) { > >> - unsigned char s0 = ftdi->bulk_in_buffer[0]; > >> - unsigned char s1 = ftdi->bulk_in_buffer[1]; > >> - empty_packets += 1; > >> - if (s0 == 0x31 && s1 == 0x60) { > >> - if (retry_on_empty-- > 0) { > >> - goto more; > >> - } else > >> - return 0; > >> - } else if (s0 == 0x31 && s1 == 0x00) { > >> - if (retry_on_empty-- > 0) { > >> - goto more; > >> - } else > >> - return 0; > >> - } else { > >> - if (retry_on_empty-- > 0) { > >> - goto more; > >> - } else > >> - return 0; > >> - } > >> - } else if (packet_bytes == 1) { > >> - if (retry_on_empty-- > 0) { > >> - goto more; > >> - } else > >> - return 0; > > > > Are you _sure_ that these lines are not needed and that the compiler is > > not really seeing them? As it doesn't look that way to me, what am I > > missing? > > I checked and make sure that All these if/else if branch just do the same thing: > > if (retry_on_empty-- > 0) { > goto more; > } else > return 0; > > so it can be merged into the last else branch. > > Also the variable 'empty_packets' doesn't use in any place, except for self increment Don't do two different things in the same patch :)
On 2019/1/23 21:41, Greg KH wrote: > On Wed, Jan 23, 2019 at 09:17:38PM +0800, YueHaibing wrote: >> On 2019/1/23 20:43, Greg KH wrote: >>> On Wed, Jan 23, 2019 at 08:34:42PM +0800, YueHaibing wrote: >>>> ./drivers/usb/misc/ftdi-elan.c:972:10-12: WARNING: possible condition with no effect (if == else) >>>> ./drivers/usb/misc/ftdi-elan.c:983:9-11: WARNING: possible condition with no effect (if == else) >>>> ./drivers/usb/misc/ftdi-elan.c:2052:11-13: WARNING: possible condition with no effect (if == else) >>>> >>>> Signed-off-by: YueHaibing <yuehaibing@huawei.com> >>> >>> You can not just provide the output of a tool as a changelog text, >>> sorry. >>> >>> Please explain what those lines mean, and why you are making the change >>> that you are. >> >> ok, will do that. >> >>> >>>> --- >>>> drivers/usb/misc/ftdi-elan.c | 26 -------------------------- >>>> 1 file changed, 26 deletions(-) >>>> >>>> diff --git a/drivers/usb/misc/ftdi-elan.c b/drivers/usb/misc/ftdi-elan.c >>>> index 76c718a..257efac 100644 >>>> --- a/drivers/usb/misc/ftdi-elan.c >>>> +++ b/drivers/usb/misc/ftdi-elan.c >>>> @@ -915,7 +915,6 @@ static int ftdi_elan_respond_engine(struct usb_ftdi *ftdi) >>>> int bytes_read = 0; >>>> int retry_on_empty = 1; >>>> int retry_on_timeout = 3; >>>> - int empty_packets = 0; >>>> read:{ >>>> int packet_bytes = 0; >>>> int retval = usb_bulk_msg(ftdi->udev, >>>> @@ -960,31 +959,6 @@ read:{ >>>> dev_err(&ftdi->udev->dev, "error = %d with packet_bytes = %d with total %d bytes%s\n", >>>> retval, packet_bytes, bytes_read, diag); >>>> return retval; >>>> - } else if (packet_bytes == 2) { >>>> - unsigned char s0 = ftdi->bulk_in_buffer[0]; >>>> - unsigned char s1 = ftdi->bulk_in_buffer[1]; >>>> - empty_packets += 1; >>>> - if (s0 == 0x31 && s1 == 0x60) { >>>> - if (retry_on_empty-- > 0) { >>>> - goto more; >>>> - } else >>>> - return 0; >>>> - } else if (s0 == 0x31 && s1 == 0x00) { >>>> - if (retry_on_empty-- > 0) { >>>> - goto more; >>>> - } else >>>> - return 0; >>>> - } else { >>>> - if (retry_on_empty-- > 0) { >>>> - goto more; >>>> - } else >>>> - return 0; >>>> - } >>>> - } else if (packet_bytes == 1) { >>>> - if (retry_on_empty-- > 0) { >>>> - goto more; >>>> - } else >>>> - return 0; >>> >>> Are you _sure_ that these lines are not needed and that the compiler is >>> not really seeing them? As it doesn't look that way to me, what am I >>> missing? >> >> I checked and make sure that All these if/else if branch just do the same thing: >> >> if (retry_on_empty-- > 0) { >> goto more; >> } else >> return 0; >> >> so it can be merged into the last else branch. >> >> Also the variable 'empty_packets' doesn't use in any place, except for self increment > > Don't do two different things in the same patch :) Thanks, I will split it into two. > > > . >
diff --git a/drivers/usb/misc/ftdi-elan.c b/drivers/usb/misc/ftdi-elan.c index 76c718a..257efac 100644 --- a/drivers/usb/misc/ftdi-elan.c +++ b/drivers/usb/misc/ftdi-elan.c @@ -915,7 +915,6 @@ static int ftdi_elan_respond_engine(struct usb_ftdi *ftdi) int bytes_read = 0; int retry_on_empty = 1; int retry_on_timeout = 3; - int empty_packets = 0; read:{ int packet_bytes = 0; int retval = usb_bulk_msg(ftdi->udev, @@ -960,31 +959,6 @@ read:{ dev_err(&ftdi->udev->dev, "error = %d with packet_bytes = %d with total %d bytes%s\n", retval, packet_bytes, bytes_read, diag); return retval; - } else if (packet_bytes == 2) { - unsigned char s0 = ftdi->bulk_in_buffer[0]; - unsigned char s1 = ftdi->bulk_in_buffer[1]; - empty_packets += 1; - if (s0 == 0x31 && s1 == 0x60) { - if (retry_on_empty-- > 0) { - goto more; - } else - return 0; - } else if (s0 == 0x31 && s1 == 0x00) { - if (retry_on_empty-- > 0) { - goto more; - } else - return 0; - } else { - if (retry_on_empty-- > 0) { - goto more; - } else - return 0; - } - } else if (packet_bytes == 1) { - if (retry_on_empty-- > 0) { - goto more; - } else - return 0; } else { if (retry_on_empty-- > 0) { goto more;
./drivers/usb/misc/ftdi-elan.c:972:10-12: WARNING: possible condition with no effect (if == else) ./drivers/usb/misc/ftdi-elan.c:983:9-11: WARNING: possible condition with no effect (if == else) ./drivers/usb/misc/ftdi-elan.c:2052:11-13: WARNING: possible condition with no effect (if == else) Signed-off-by: YueHaibing <yuehaibing@huawei.com> --- drivers/usb/misc/ftdi-elan.c | 26 -------------------------- 1 file changed, 26 deletions(-)