Subject: Re: linux-next: manual merge of the v4l-dvb tree with the i2c tree

From: Romain Gantois <[email-masked]>
Date: Fri, 30 May 2025 10:13:58 +0200

Hi Stephen,

On Thursday, 29 May 2025 04:49:29 CEST Stephen Rothwell wrote:
> Hi all,
> 
> On Mon, 28 Apr 2025 11:30:52 +1000 Stephen Rothwell <[email-masked]> 
wrote:
> > On Mon, 28 Apr 2025 11:22:00 +1000 Stephen Rothwell <[email-masked]> 
wrote:
> > > On Mon, 28 Apr 2025 10:49:05 +1000 Stephen Rothwell 
<[email-masked]> wrote:
> > > > Today's linux-next merge of the v4l-dvb tree got a conflict in:
> > > >   drivers/media/i2c/ds90ub960.c
> > > > 
> > > > between commits:
> > > >   3ec29d51b546 ("media: i2c: ds90ub960: Protect alias_use_mask with a
> > > >   mutex")
> > > >   818bd489f137 ("i2c: use client addresses directly in ATR interface")
> > > > 
> > > > from the i2c tree and commits:
> > > >   24868501a744 ("media: i2c: ds90ub9xx: Add err parameter to
> > > >   read/write funcs") 2ca499384e98 ("media: i2c: ds90ub960: Add RX
> > > >   port iteration support")> > > 
> > > > from the v4l-dvb tree.
> > > > 
> > > > I fixed it up (see below) and can carry the fix as necessary. This
> > > > is now fixed as far as linux-next is concerned, but any non trivial
> > > > conflicts should be mentioned to your upstream maintainer when your
> > > > tree
> > > > is submitted for merging.  You may also want to consider cooperating
> > > > with the maintainer of the conflicting tree to minimise any
> > > > particularly
> > > > complex conflicts.
> > > 
> > > The actual resolution is below ...
> > 
> > I hit the wrong key :-(   Resolution below.
> 
> This is now a conflict between the i2c tree and Linus' tree.

Below is the resolution I came up with.

Thanks,

-- 
Romain Gantois, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

diff --cc drivers/media/i2c/ds90ub960.c
index ed9ace1a54766,94b20ba6cb86f..54c2546551451
--- a/drivers/media/i2c/ds90ub960.c
+++ b/drivers/media/i2c/ds90ub960.c
@@@ -1271,10 -1056,11 +1274,12 @@@ static int ub960_atr_attach_addr(struc
        struct ub960_rxport *rxport = priv->rxports[chan_id];
        struct device *dev = &priv->client->dev;
        unsigned int reg_idx;
 +      int ret = 0;
  
-       for (reg_idx = 0; reg_idx < ARRAY_SIZE(rxport->aliased_clients); 
reg_idx++) {
-               if (!rxport->aliased_clients[reg_idx])
+       guard(mutex)(&rxport->aliased_addrs_lock);
+ 
+       for (reg_idx = 0; reg_idx < ARRAY_SIZE(rxport->aliased_addrs); 
reg_idx++) {
+               if (!rxport->aliased_addrs[reg_idx])
                        break;
        }
  
@@@ -1283,18 -1069,15 +1288,18 @@@
                return -EADDRNOTAVAIL;
        }
  
-       rxport->aliased_clients[reg_idx] = client;
+       rxport->aliased_addrs[reg_idx] = addr;
  
        ub960_rxport_write(priv, chan_id, UB960_RR_SLAVE_ID(reg_idx),
-                          client->addr << 1, &ret);
 -                         addr << 1);
++                         addr << 1, &ret);
        ub960_rxport_write(priv, chan_id, UB960_RR_SLAVE_ALIAS(reg_idx),
 -                         alias << 1);
 +                         alias << 1, &ret);
 +
 +      if (ret)
 +              return ret;
  
        dev_dbg(dev, "rx%u: client 0x%02x assigned alias 0x%02x at slot %u\n",
-               rxport->nport, client->addr, alias, reg_idx);
+               rxport->nport, addr, alias, reg_idx);
  
        return 0;
  }
@@@ -1306,10 -1089,11 +1311,12 @@@ static void ub960_atr_detach_addr(struc
        struct ub960_rxport *rxport = priv->rxports[chan_id];
        struct device *dev = &priv->client->dev;
        unsigned int reg_idx;
 +      int ret;
  
-       for (reg_idx = 0; reg_idx < ARRAY_SIZE(rxport->aliased_clients); 
reg_idx++) {
-               if (rxport->aliased_clients[reg_idx] == client)
+       guard(mutex)(&rxport->aliased_addrs_lock);
+ 
+       for (reg_idx = 0; reg_idx < ARRAY_SIZE(rxport->aliased_addrs); 
reg_idx++) {
+               if (rxport->aliased_addrs[reg_idx] == addr)
                        break;
        }
  
@@@ -1319,18 -1103,12 +1326,18 @@@
                return;
        }
  
-       rxport->aliased_clients[reg_idx] = NULL;
+       rxport->aliased_addrs[reg_idx] = 0;
  
 -      ub960_rxport_write(priv, chan_id, UB960_RR_SLAVE_ALIAS(reg_idx), 0);
 +      ret = ub960_rxport_write(priv, chan_id, UB960_RR_SLAVE_ALIAS(reg_idx),
 +                               0, NULL);
 +      if (ret) {
 +              dev_err(dev, "rx%u: unable to fully unmap client 0x%02x: 
%d\n",
 +                      rxport->nport, client->addr, ret);
 +              return;
 +      }
  
        dev_dbg(dev, "rx%u: client 0x%02x released at slot %u\n", rxport-
>nport,
-               client->addr, reg_idx);
+               addr, reg_idx);
  }
  
  static const struct i2c_atr_ops ub960_atr_ops = {
@@@ -4370,12 -3231,21 +4376,14 @@@ static void ub960_txport_free_ports(str
  
  static void ub960_rxport_free_ports(struct ub960_data *priv)
  {
 -      unsigned int nport;
 -
 -      for (nport = 0; nport < priv->hw_data->num_rxports; nport++) {
 -              struct ub960_rxport *rxport = priv->rxports[nport];
 -
 -              if (!rxport)
 -                      continue;
 -
 -              fwnode_handle_put(rxport->source.ep_fwnode);
 -              fwnode_handle_put(rxport->ser.fwnode);
 +      for_each_active_rxport(priv, it) {
 +              fwnode_handle_put(it.rxport->source.ep_fwnode);
 +              fwnode_handle_put(it.rxport->ser.fwnode);
  
+               mutex_destroy(&rxport->aliased_addrs_lock);
+ 
 -              kfree(rxport);
 -              priv->rxports[nport] = NULL;
 +              kfree(it.rxport);
 +              priv->rxports[it.nport] = NULL;
        }
  }