| Message ID | 20200825092037.7ded996d@endymion |
|---|---|
| State | Accepted |
| Delegated to: | Bartosz Golaszewski |
| Headers | show |
| Series | [v2] eeprom: at24: Tidy at24_read() | expand |
On Tue, Aug 25, 2020 at 9:20 AM Jean Delvare <jdelvare@suse.de> wrote: > > The elegant code in at24_read() has the drawback that we now need > to make a copy of all parameters to pass them to the post-processing > callback function if there is one. Rewrite the loop in such a way that > the parameters are not modified, so saving them is no longer needed. > > Signed-off-by: Jean Delvare <jdelvare@suse.de> > Cc: Bartosz Golaszewski <bgolaszewski@baylibre.com> > Cc: Arnd Bergmann <arnd@arndb.de> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > --- > This has the drawback of creating an asymetry with at24_write(), so > I'm not 100% if we want to apply this. If anyone has a better idea, > please let me know. > > Changes since v1: > * Turn the "while" loop into a "for" loop to make the code neater. > Suggested by Bartosz. > > drivers/misc/eeprom/at24.c | 14 ++++---------- > 1 file changed, 4 insertions(+), 10 deletions(-) > > --- linux-5.7.orig/drivers/misc/eeprom/at24.c 2020-08-24 19:25:52.967519228 +0200 > +++ linux-5.7/drivers/misc/eeprom/at24.c 2020-08-25 08:25:23.033990857 +0200 > @@ -422,10 +422,7 @@ static int at24_read(void *priv, unsigne > struct at24_data *at24; > struct device *dev; > char *buf = val; > - int ret; > - unsigned int orig_off = off; > - char *orig_buf = buf; > - size_t orig_count = count; > + int i, ret; > > at24 = priv; > dev = at24_base_client_dev(at24); > @@ -448,16 +445,13 @@ static int at24_read(void *priv, unsigne > */ > mutex_lock(&at24->lock); > > - while (count) { > - ret = at24_regmap_read(at24, buf, off, count); > + for (i = 0; count; i += ret, count -= ret) { > + ret = at24_regmap_read(at24, buf + i, off + i, count); > if (ret < 0) { > mutex_unlock(&at24->lock); > pm_runtime_put(dev); > return ret; > } > - buf += ret; > - off += ret; > - count -= ret; > } > > mutex_unlock(&at24->lock); > @@ -465,7 +459,7 @@ static int at24_read(void *priv, unsigne > pm_runtime_put(dev); > > if (unlikely(at24->read_post)) > - at24->read_post(orig_off, orig_buf, orig_count); > + at24->read_post(off, buf, i); > > return 0; > } > > > -- > Jean Delvare > SUSE L3 Support Patch queued for v5.10. Thanks! Bartosz
--- linux-5.7.orig/drivers/misc/eeprom/at24.c 2020-08-24 19:25:52.967519228 +0200 +++ linux-5.7/drivers/misc/eeprom/at24.c 2020-08-25 08:25:23.033990857 +0200 @@ -422,10 +422,7 @@ static int at24_read(void *priv, unsigne struct at24_data *at24; struct device *dev; char *buf = val; - int ret; - unsigned int orig_off = off; - char *orig_buf = buf; - size_t orig_count = count; + int i, ret; at24 = priv; dev = at24_base_client_dev(at24); @@ -448,16 +445,13 @@ static int at24_read(void *priv, unsigne */ mutex_lock(&at24->lock); - while (count) { - ret = at24_regmap_read(at24, buf, off, count); + for (i = 0; count; i += ret, count -= ret) { + ret = at24_regmap_read(at24, buf + i, off + i, count); if (ret < 0) { mutex_unlock(&at24->lock); pm_runtime_put(dev); return ret; } - buf += ret; - off += ret; - count -= ret; } mutex_unlock(&at24->lock); @@ -465,7 +459,7 @@ static int at24_read(void *priv, unsigne pm_runtime_put(dev); if (unlikely(at24->read_post)) - at24->read_post(orig_off, orig_buf, orig_count); + at24->read_post(off, buf, i); return 0; }
The elegant code in at24_read() has the drawback that we now need to make a copy of all parameters to pass them to the post-processing callback function if there is one. Rewrite the loop in such a way that the parameters are not modified, so saving them is no longer needed. Signed-off-by: Jean Delvare <jdelvare@suse.de> Cc: Bartosz Golaszewski <bgolaszewski@baylibre.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- This has the drawback of creating an asymetry with at24_write(), so I'm not 100% if we want to apply this. If anyone has a better idea, please let me know. Changes since v1: * Turn the "while" loop into a "for" loop to make the code neater. Suggested by Bartosz. drivers/misc/eeprom/at24.c | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-)