linux-kernel - Re: [PATCH] firewire: reread config ROM when device reset the bus

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Date:	Mon, 03 Mar 2008 17:51:33 +0100
From:	Stefan Richter <stefanr@...6.in-berlin.de>
To:	Kristian Høgsberg <krh@...planet.net>
CC:	linux1394-devel@...ts.sourceforge.net, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] firewire: reread config ROM when device reset the bus

Kristian Høgsberg wrote:
> I would just add a
> 
>   case REREAD_BIB_CHANGED:
>     break;
> 
> to the switch to make that clear,

Yes, that's nicer.

> but otherwise
> 
> Signed-off-by: Kristian Høgsberg <krh@...hat.com>

Thanks.

...
>>  --- linux.orig/drivers/firewire/fw-cdev.c
>>  +++ linux/drivers/firewire/fw-cdev.c
>>  @@ -269,20 +270,25 @@ static int ioctl_get_info(struct client
>>   {
>>         struct fw_cdev_get_info *get_info = buffer;
>>         struct fw_cdev_event_bus_reset bus_reset;
>>  +       struct fw_device *device = client->device;
>>  +       unsigned long ret = 0;
>>
>>         client->version = get_info->version;
>>         get_info->version = FW_CDEV_VERSION;
>>
>>  +       down(&device->device.sem);
>>         if (get_info->rom != 0) {
>>                 void __user *uptr = u64_to_uptr(get_info->rom);
>>                 size_t want = get_info->rom_length;
>>  -               size_t have = client->device->config_rom_length * 4;
>>  +               size_t have;
>>
>>  -               if (copy_to_user(uptr, client->device->config_rom,
>>  -                                min(want, have)))
>>  -                       return -EFAULT;
>>  +               have = device->config_rom_length * 4;
>>  +               ret = copy_to_user(uptr, device->config_rom, min(want, have));
>>         }
>>  -       get_info->rom_length = client->device->config_rom_length * 4;
>>  +       get_info->rom_length = device->config_rom_length * 4;
>>  +       up(&device->device.sem);
>>  +       if (ret != 0)
>>  +               return -EFAULT;
>>
>>         client->bus_reset_closure = get_info->bus_reset_closure;
>>         if (get_info->bus_reset != 0) {

Maybe I should rather use fw-device.c::idr_rwsem instead of device.sem, 
to have better control over who takes the mutex when.  Could also be a 
new dedicated mutex but we don't want to end up with too many of them... 
Do you have an opinion?
-- 
Stefan Richter
-=====-==--- --== ---==
http://arcgraph.de/sr/
--
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