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Message-ID: <2560973.EJVuxm6PHt@vostro.rjw.lan>
Date: Fri, 02 Aug 2013 15:43:58 +0200
From: "Rafael J. Wysocki" <rjw@...k.pl>
To: Lan Tianyu <lantianyu1986@...il.com>
Cc: ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
LKML <linux-kernel@...r.kernel.org>,
Bjorn Helgaas <bhelgaas@...gle.com>,
Toshi Kani <toshi.kani@...com>
Subject: Re: [PATCH] ACPI: Do not fail acpi_bind_one() if device is already bound correctly
On Friday, August 02, 2013 10:48:49 AM Lan Tianyu wrote:
> 2013/8/2 Rafael J. Wysocki <rjw@...k.pl>:
> > From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> >
> > Modify acpi_bind_one() so that it doesn't fail if the device
> > represented by its first argument has already been bound to the
> > given ACPI handle (second argument), because that is not a good
> > enough reason for returning an error code.
> >
> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> > ---
> > drivers/acpi/glue.c | 15 +++++++++++----
> > 1 file changed, 11 insertions(+), 4 deletions(-)
> >
> > Index: linux-pm/drivers/acpi/glue.c
> > ===================================================================
> > --- linux-pm.orig/drivers/acpi/glue.c
> > +++ linux-pm/drivers/acpi/glue.c
> > @@ -143,7 +143,10 @@ int acpi_bind_one(struct device *dev, ac
> > list_for_each_entry(pn, &acpi_dev->physical_node_list, node)
> > if (pn->dev == dev) {
> > dev_warn(dev, "Already associated with ACPI node\n");
> > - goto err_free;
> > + if (ACPI_HANDLE(dev) == handle)
> > + retval = 0;
> > +
> > + goto out_free;
> > }
> >
> > /* allocate physical node id according to physical_node_id_bitmap */
> > @@ -152,7 +155,7 @@ int acpi_bind_one(struct device *dev, ac
> > ACPI_MAX_PHYSICAL_NODE);
> > if (physical_node->node_id >= ACPI_MAX_PHYSICAL_NODE) {
> > retval = -ENOSPC;
> > - goto err_free;
> > + goto out_free;
> > }
> >
> > set_bit(physical_node->node_id, acpi_dev->physical_node_id_bitmap);
> > @@ -185,10 +188,14 @@ int acpi_bind_one(struct device *dev, ac
> > put_device(dev);
> > return retval;
> >
> > - err_free:
> > + out_free:
> > mutex_unlock(&acpi_dev->physical_node_lock);
> > kfree(physical_node);
> > - goto err;
> > + if (retval)
> > + goto err;
> > +
> > + put_device(dev);
> > + return 0;
> > }
> > EXPORT_SYMBOL_GPL(acpi_bind_one);
>
> Hi Rafael:
> How about the following change?
It is incorrect, because the "problem" it attempts to "fix" is actually
intentional behavior. [And you could ask if it was intentional in the first
place instead of assuming that it was a mistake. It wasn't.]
Do you have any problems with my $subject patch?
Rafael
>
> diff --git a/drivers/acpi/glue.c b/drivers/acpi/glue.c
> index f70cc45..35f375e 100644
> --- a/drivers/acpi/glue.c
> +++ b/drivers/acpi/glue.c
> @@ -183,19 +183,15 @@ int acpi_bind_one(struct device *dev, acpi_handle handle)
>
> return 0;
>
> - err:
> - ACPI_HANDLE_SET(dev, NULL);
> - put_device(dev);
> - return retval;
> -
> out_free:
> mutex_unlock(&acpi_dev->physical_node_lock);
> kfree(physical_node);
> - if (retval)
> - goto err;
>
> + err:
> + if (retval)
> + ACPI_HANDLE_SET(dev, NULL);
> put_device(dev);
> - return 0;
> + return retval;
> }
> EXPORT_SYMBOL_GPL(acpi_bind_one);
> ---------------
>
> When I reviewed this patch, found the dev's acpi handle always
> is set to NULL if there is error. This seems make no sense for
> the case that the handle has been set to dev before binding.
>
> For this case, the acpi handle has been found before binding.
> Actually, the device driver could control any resources under ACPI
> node even if the binding failed. So adding one flag to differentiate
> it.
>
> diff --git a/drivers/acpi/glue.c b/drivers/acpi/glue.c
> index 35f375e..c868e51 100644
> --- a/drivers/acpi/glue.c
> +++ b/drivers/acpi/glue.c
> @@ -113,6 +113,7 @@ int acpi_bind_one(struct device *dev, acpi_handle handle)
> acpi_status status;
> struct acpi_device_physical_node *physical_node, *pn;
> char physical_node_name[sizeof(PHYSICAL_NODE_STRING) + 2];
> + bool has_handle = false;
> int retval = -EINVAL;
>
> if (ACPI_HANDLE(dev)) {
> @@ -121,6 +122,7 @@ int acpi_bind_one(struct device *dev, acpi_handle handle)
> return -EINVAL;
> } else {
> handle = ACPI_HANDLE(dev);
> + has_handle = true;
> }
> }
> if (!handle)
> @@ -188,7 +190,7 @@ int acpi_bind_one(struct device *dev, acpi_handle handle)
> kfree(physical_node);
>
> err:
> - if (retval)
> + if (retval && !has_handle)
> ACPI_HANDLE_SET(dev, NULL);
> put_device(dev);
> return retval;
>
>
>
> >
> >
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-acpi" in
> > the body of a message to majordomo@...r.kernel.org
> > More majordomo info at http://vger.kernel.org/majordomo-info.html
>
>
>
>
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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