| Message ID | 20190730175555.14098-2-wsa+renesas@sang-engineering.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | media: ir-kbd-i2c: convert to devm_i2c_new_dummy_device & minor cleanup | expand |
Em Tue, 30 Jul 2019 19:55:54 +0200 Wolfram Sang <wsa+renesas@sang-engineering.com> escreveu: > Convert this driver to use the new i2c_new_dummy_device() call and bail > out if the dummy device cannot be registered to make failure more > visible to the user. > Please don't do that. At first glance, devm_* sounds a good idea, but we had enough issues using it on media system. I don't mind mind much if some SoC specific would use it, but doing it on generic drivers is a very bad idea. We have removed almost all devm_* calls from the media system. The problem with devm is that it the de-allocation routines aren't called during device unbind. They happen a way later, only when the device itself is physically removed, or the driver is removed. That caused lots of headaches to debug memory lifetime issues on media. > Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> > --- > > Change since v1: > > * reworded commit message because there was no NULL ptr access > > drivers/media/i2c/ir-kbd-i2c.c | 13 +++++-------- > 1 file changed, 5 insertions(+), 8 deletions(-) > > diff --git a/drivers/media/i2c/ir-kbd-i2c.c b/drivers/media/i2c/ir-kbd-i2c.c > index 876d7587a1da..f46717052efc 100644 > --- a/drivers/media/i2c/ir-kbd-i2c.c > +++ b/drivers/media/i2c/ir-kbd-i2c.c > @@ -885,9 +885,12 @@ static int ir_probe(struct i2c_client *client, const struct i2c_device_id *id) > INIT_DELAYED_WORK(&ir->work, ir_work); > > if (probe_tx) { > - ir->tx_c = i2c_new_dummy(client->adapter, 0x70); > - if (!ir->tx_c) { > + ir->tx_c = devm_i2c_new_dummy_device(&client->dev, > + client->adapter, 0x70); > + if (IS_ERR(ir->tx_c)) { > dev_err(&client->dev, "failed to setup tx i2c address"); > + err = PTR_ERR(ir->tx_c); > + goto err_out_free; > } else if (!zilog_init(ir)) { > ir->carrier = 38000; > ir->duty_cycle = 40; > @@ -904,9 +907,6 @@ static int ir_probe(struct i2c_client *client, const struct i2c_device_id *id) > return 0; > > err_out_free: > - if (ir->tx_c) > - i2c_unregister_device(ir->tx_c); > - > /* Only frees rc if it were allocated internally */ > rc_free_device(rc); > return err; > @@ -919,9 +919,6 @@ static int ir_remove(struct i2c_client *client) > /* kill outstanding polls */ > cancel_delayed_work_sync(&ir->work); > > - if (ir->tx_c) > - i2c_unregister_device(ir->tx_c); > - > /* unregister device */ > rc_unregister_device(ir->rc); > Thanks, Mauro
On Sat, Aug 03, 2019 at 01:17:49PM -0300, Mauro Carvalho Chehab wrote: > Em Tue, 30 Jul 2019 19:55:54 +0200 > Wolfram Sang <wsa+renesas@sang-engineering.com> escreveu: > > > Convert this driver to use the new i2c_new_dummy_device() call and bail > > out if the dummy device cannot be registered to make failure more > > visible to the user. > > > > Please don't do that. > > At first glance, devm_* sounds a good idea, but we had enough issues > using it on media system. > > I don't mind mind much if some SoC specific would use it, but doing > it on generic drivers is a very bad idea. We have removed almost all > devm_* calls from the media system. > > The problem with devm is that it the de-allocation routines aren't > called during device unbind. They happen a way later, only when the > device itself is physically removed, or the driver is removed. Yes, good point. > That caused lots of headaches to debug memory lifetime issues on > media. Indeed this becomes much more complex. Explicit freeing is much better. Thanks, Sean
diff --git a/drivers/media/i2c/ir-kbd-i2c.c b/drivers/media/i2c/ir-kbd-i2c.c index 876d7587a1da..f46717052efc 100644 --- a/drivers/media/i2c/ir-kbd-i2c.c +++ b/drivers/media/i2c/ir-kbd-i2c.c @@ -885,9 +885,12 @@ static int ir_probe(struct i2c_client *client, const struct i2c_device_id *id) INIT_DELAYED_WORK(&ir->work, ir_work); if (probe_tx) { - ir->tx_c = i2c_new_dummy(client->adapter, 0x70); - if (!ir->tx_c) { + ir->tx_c = devm_i2c_new_dummy_device(&client->dev, + client->adapter, 0x70); + if (IS_ERR(ir->tx_c)) { dev_err(&client->dev, "failed to setup tx i2c address"); + err = PTR_ERR(ir->tx_c); + goto err_out_free; } else if (!zilog_init(ir)) { ir->carrier = 38000; ir->duty_cycle = 40; @@ -904,9 +907,6 @@ static int ir_probe(struct i2c_client *client, const struct i2c_device_id *id) return 0; err_out_free: - if (ir->tx_c) - i2c_unregister_device(ir->tx_c); - /* Only frees rc if it were allocated internally */ rc_free_device(rc); return err; @@ -919,9 +919,6 @@ static int ir_remove(struct i2c_client *client) /* kill outstanding polls */ cancel_delayed_work_sync(&ir->work); - if (ir->tx_c) - i2c_unregister_device(ir->tx_c); - /* unregister device */ rc_unregister_device(ir->rc);
Convert this driver to use the new i2c_new_dummy_device() call and bail out if the dummy device cannot be registered to make failure more visible to the user. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> --- Change since v1: * reworded commit message because there was no NULL ptr access drivers/media/i2c/ir-kbd-i2c.c | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-)