Re: [PATCH] PCI: export MSI mode using attributes, not kobjects

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Thu, Dec 12, 2013 at 03:17:50PM -0800, Yinghai Lu wrote:
> On Sat, Dec 7, 2013 at 12:41 PM, Bjorn Helgaas <bhelgaas@google.com> wrote:
> > On Wed, Nov 27, 2013 at 11:46 AM, Greg Kroah-Hartman
> > <gregkh@linuxfoundation.org> wrote:
> >> From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> >>
> >> The PCI MSI sysfs code is a mess with kobjects for things that don't
> >> really need to be kobjects.  This patch creates attributes dynamically
> >> for the MSI interrupts instead of using kobjects.
> >>
> >> Note, this removes a directory from the current MSI interrupt sysfs
> >> code:
> >>
> >> old MSI kobjects:
> >> pci_device
> >>    └── msi_irqs
> >>        └── 40
> >>            └── mode
> >>
> >> new MSI attributes:
> >> pci_device
> >>    └── msi_irqs
> >>        └── 40
> >>
> >> As there was only one file "mode" with the kobject model, the interrupt
> >> number is now a file that returns the "mode" of the interrupt (msi vs.
> >> msix).
> >>
> >> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> >
> > I added the acks from Neil and Veaceslav, folded in the
> > Documentation/ABI update, and applied the whole thing to my pci/misc
> > branch for v3.14.  Thanks!
> 
> got:
> [   71.429735] BUG: key ffff887fcf082a58 not in .data!
> [   71.429737] ------------[ cut here ]------------
> [   71.429742] WARNING: CPU: 0 PID: 4 at kernel/locking/lockdep.c:2987 lockdep_i
> nit_map+0x127/0x5b0()
> [   71.429743] DEBUG_LOCKS_WARN_ON(1)
> [   71.429744] Modules linked in:
> [   71.429747] CPU: 0 PID: 4 Comm: kworker/0:0 Tainted: G          I  3.13.0-rc3
> -yh-01187-ge0e4e4e-dirty #45
> [   71.429757] Workqueue: events work_for_cpu_fn
> [   71.429792]  0000000000000009 ffff881fcf95da58 ffffffff82020475 ffff881fcf95d
> aa0
> [   71.429800]  ffff881fcf95da90 ffffffff81097c3d ffff887fcf082a58 ffff88dfcec1a
> d28
> [   71.429809]  0000000000000000 0000000000000000 ffff889fcf2eecd0 ffff881fcf95d
> af0
> [   71.429809] Call Trace:
> [   71.429814]  [<ffffffff82020475>] dump_stack+0x45/0x56
> [   71.429818]  [<ffffffff81097c3d>] warn_slowpath_common+0x7d/0xa0
> [   71.429822]  [<ffffffff81097cac>] warn_slowpath_fmt+0x4c/0x50
> [   71.429826]  [<ffffffff810e3d97>] lockdep_init_map+0x127/0x5b0
> [   71.429835]  [<ffffffff81242fe8>] ? sysfs_new_dirent+0x98/0x140
> [   71.429839]  [<ffffffff81242033>] sysfs_add_file_mode_ns+0x63/0xc0
> [   71.429843]  [<ffffffff8124491d>] internal_create_group+0x18d/0x260
> [   71.429853]  [<ffffffff81556345>] ? populate_msi_sysfs+0x185/0x1d0
> [   71.429857]  [<ffffffff81244a52>] sysfs_create_groups+0x42/0xa0
> [   71.429861]  [<ffffffff81556367>] populate_msi_sysfs+0x1a7/0x1d0
> [   71.429865]  [<ffffffff81556b67>] pci_enable_msi_block+0x1f7/0x2a0
> [   71.429870]  [<ffffffff81549795>] pcie_port_device_register+0x335/0x520
> [   71.429874]  [<ffffffff81549f08>] pcie_portdrv_probe+0x68/0xa0
> [   71.429883]  [<ffffffff8153cf75>] local_pci_probe+0x45/0xa0
> [   71.429887]  [<ffffffff810b0af4>] work_for_cpu_fn+0x14/0x20
> [   71.429891]  [<ffffffff810b431b>] process_one_work+0x28b/0x4a0
> [   71.429895]  [<ffffffff810b4292>] ? process_one_work+0x202/0x4a0
> [   71.429899]  [<ffffffff810b55db>] worker_thread+0x26b/0x3a0
> [   71.429903]  [<ffffffff810e262d>] ? trace_hardirqs_on+0xd/0x10
> [   71.429906]  [<ffffffff810b5370>] ? manage_workers.isra.17+0x340/0x340
> [   71.429912]  [<ffffffff810bc031>] kthread+0x111/0x120
> [   71.429919]  [<ffffffff810cddab>] ? local_clock+0x2b/0x40
> [   71.429923]  [<ffffffff810bbf20>] ? kthread_stop+0xf0/0xf0
> [   71.429927]  [<ffffffff8203842c>] ret_from_fork+0x7c/0xb0
> [   71.429931]  [<ffffffff810bbf20>] ? kthread_stop+0xf0/0xf0
> [   71.429933] ---[ end trace c511e3d74efea94e ]---
> 
> looks like Greg forgot adding attr init.
> 
> Can you fold attached patch into Greg's patch ?
> 
> Index: linux-2.6/drivers/pci/msi.c
> ===================================================================
> --- linux-2.6.orig/drivers/pci/msi.c
> +++ linux-2.6/drivers/pci/msi.c
> @@ -547,6 +547,7 @@ static int populate_msi_sysfs(struct pci
>                 msi_dev_attr = kzalloc(sizeof(*msi_dev_attr), GFP_KERNEL);
>                 if (!msi_dev_attr)
>                         return -ENOMEM;
> +               sysfs_attr_init(&msi_dev_attr->attr);
>                 sprintf(name, "%d", entry->irq);
>                 msi_dev_attr->attr.name = name;
>                 msi_dev_attr->attr.mode = S_IRUGO;

> ---
>  drivers/pci/msi.c |    1 +
>  1 file changed, 1 insertion(+)
> 
> Index: linux-2.6/drivers/pci/msi.c
> ===================================================================
> --- linux-2.6.orig/drivers/pci/msi.c
> +++ linux-2.6/drivers/pci/msi.c
> @@ -547,6 +547,7 @@ static int populate_msi_sysfs(struct pci
>  		msi_dev_attr = kzalloc(sizeof(*msi_dev_attr), GFP_KERNEL);
>  		if (!msi_dev_attr)
>  			return -ENOMEM;
> +		sysfs_attr_init(&msi_dev_attr->attr);
>  		sprintf(name, "%d", entry->irq);
>  		msi_dev_attr->attr.name = name;
>  		msi_dev_attr->attr.mode = S_IRUGO;

Ah, crap, yes, you are right, my fault, very nice catch.

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

greg k-h