* [PATCH][UHCI-DEBUG] Don't kmalloc with BKL held
@ 2009-10-02 9:12 Sven-Thorsten Dietrich
2009-10-02 9:20 ` Frederik Deweerdt
2009-10-02 12:01 ` Oliver Neukum
0 siblings, 2 replies; 6+ messages in thread
From: Sven-Thorsten Dietrich @ 2009-10-02 9:12 UTC (permalink / raw)
To: LKML; +Cc: linux-rt-users
Subject: Don't kmalloc with BKL held.
From: Sven-Thorsten Dietrich <sdietrich@suse.de>
I'm eyeballing this file for complete removal of lock_kernel but
at first glance, we definitely don't need BKL to kmalloc().
Signed-off-by: Sven-Thorsten Dietrich <sdietrich@suse.de>
diff --git a/drivers/usb/host/uhci-debug.c b/drivers/usb/host/uhci-debug.c
index e52b954..325d508 100644
--- a/drivers/usb/host/uhci-debug.c
+++ b/drivers/usb/host/uhci-debug.c
@@ -497,7 +497,6 @@ static int uhci_debug_open(struct inode *inode, struct file *file)
int ret = -ENOMEM;
unsigned long flags;
- lock_kernel();
up = kmalloc(sizeof(*up), GFP_KERNEL);
if (!up)
goto out;
@@ -509,6 +508,8 @@ static int uhci_debug_open(struct inode *inode, struct file *file)
}
up->size = 0;
+
+ lock_kernel();
spin_lock_irqsave(&uhci->lock, flags);
if (uhci->is_initialized)
up->size = uhci_sprint_schedule(uhci, up->data, MAX_OUTPUT);
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH][UHCI-DEBUG] Don't kmalloc with BKL held
2009-10-02 9:12 [PATCH][UHCI-DEBUG] Don't kmalloc with BKL held Sven-Thorsten Dietrich
@ 2009-10-02 9:20 ` Frederik Deweerdt
2009-10-03 12:35 ` Sven-Thorsten Dietrich
2009-10-02 12:01 ` Oliver Neukum
1 sibling, 1 reply; 6+ messages in thread
From: Frederik Deweerdt @ 2009-10-02 9:20 UTC (permalink / raw)
To: Sven-Thorsten Dietrich; +Cc: LKML, linux-rt-users
Hi Sven-Thorsten,
On Fri, Oct 02, 2009 at 11:12:24AM +0200, Sven-Thorsten Dietrich wrote:
> Subject: Don't kmalloc with BKL held.
> From: Sven-Thorsten Dietrich <sdietrich@suse.de>
>
> I'm eyeballing this file for complete removal of lock_kernel but
> at first glance, we definitely don't need BKL to kmalloc().
You need to move the unlock_kernel() above the out: label too.
Regards,
Frederik
>
> Signed-off-by: Sven-Thorsten Dietrich <sdietrich@suse.de>
>
>
> diff --git a/drivers/usb/host/uhci-debug.c b/drivers/usb/host/uhci-debug.c
> index e52b954..325d508 100644
> --- a/drivers/usb/host/uhci-debug.c
> +++ b/drivers/usb/host/uhci-debug.c
> @@ -497,7 +497,6 @@ static int uhci_debug_open(struct inode *inode, struct file *file)
> int ret = -ENOMEM;
> unsigned long flags;
>
> - lock_kernel();
> up = kmalloc(sizeof(*up), GFP_KERNEL);
> if (!up)
> goto out;
> @@ -509,6 +508,8 @@ static int uhci_debug_open(struct inode *inode, struct file *file)
> }
>
> up->size = 0;
> +
> + lock_kernel();
> spin_lock_irqsave(&uhci->lock, flags);
> if (uhci->is_initialized)
> up->size = uhci_sprint_schedule(uhci, up->data, MAX_OUTPUT);
>
>
> --
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^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH][UHCI-DEBUG] Don't kmalloc with BKL held
2009-10-02 9:12 [PATCH][UHCI-DEBUG] Don't kmalloc with BKL held Sven-Thorsten Dietrich
2009-10-02 9:20 ` Frederik Deweerdt
@ 2009-10-02 12:01 ` Oliver Neukum
1 sibling, 0 replies; 6+ messages in thread
From: Oliver Neukum @ 2009-10-02 12:01 UTC (permalink / raw)
To: Sven-Thorsten Dietrich; +Cc: LKML, linux-rt-users
Am Freitag, 2. Oktober 2009 11:12:24 schrieb Sven-Thorsten Dietrich:
> Subject: Don't kmalloc with BKL held.
> From: Sven-Thorsten Dietrich <sdietrich@suse.de>
>
> I'm eyeballing this file for complete removal of lock_kernel but
> at first glance, we definitely don't need BKL to kmalloc().
The reasoning is correct, but this patch screws up the error case.
You also need to move the label.
Regards
Oliver
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH][UHCI-DEBUG] Don't kmalloc with BKL held
2009-10-02 9:20 ` Frederik Deweerdt
@ 2009-10-03 12:35 ` Sven-Thorsten Dietrich
2009-10-06 7:51 ` Frederik Deweerdt
2009-10-06 10:09 ` Thomas Gleixner
0 siblings, 2 replies; 6+ messages in thread
From: Sven-Thorsten Dietrich @ 2009-10-03 12:35 UTC (permalink / raw)
To: Frederik Deweerdt; +Cc: LKML, linux-rt-users
On Fri, 2009-10-02 at 09:20 +0000, Frederik Deweerdt wrote:
> Hi Sven-Thorsten,
>
> On Fri, Oct 02, 2009 at 11:12:24AM +0200, Sven-Thorsten Dietrich wrote:
> > Subject: Don't kmalloc with BKL held.
> > From: Sven-Thorsten Dietrich <sdietrich@suse.de>
> >
> > I'm eyeballing this file for complete removal of lock_kernel but
> > at first glance, we definitely don't need BKL to kmalloc().
> You need to move the unlock_kernel() above the out: label too.
>
How about this ?
Subject: Don't kmalloc with BKL held.
From: Sven-Thorsten Dietrich sdietrich@suse.de Sat Oct 3 01:27:27 2009 -0700
Date: Sat Oct 3 01:27:27 2009 -0700:
Git: 4f62eb81e827eb857129101e49757d84ac9ee7eb
We don't need BKL to kmalloc
diff --git a/drivers/usb/host/uhci-debug.c b/drivers/usb/host/uhci-debug.c
index e52b954..3fd5602 100644
--- a/drivers/usb/host/uhci-debug.c
+++ b/drivers/usb/host/uhci-debug.c
@@ -494,32 +494,30 @@ static int uhci_debug_open(struct inode *inode, struct file *file)
{
struct uhci_hcd *uhci = inode->i_private;
struct uhci_debug *up;
- int ret = -ENOMEM;
unsigned long flags;
- lock_kernel();
up = kmalloc(sizeof(*up), GFP_KERNEL);
if (!up)
- goto out;
+ return -ENOMEM;
up->data = kmalloc(MAX_OUTPUT, GFP_KERNEL);
if (!up->data) {
kfree(up);
- goto out;
+ return -ENOMEM;
}
up->size = 0;
+
+ lock_kernel();
spin_lock_irqsave(&uhci->lock, flags);
if (uhci->is_initialized)
up->size = uhci_sprint_schedule(uhci, up->data, MAX_OUTPUT);
spin_unlock_irqrestore(&uhci->lock, flags);
file->private_data = up;
-
- ret = 0;
-out:
unlock_kernel();
- return ret;
+
+ return 0;
}
static loff_t uhci_debug_lseek(struct file *file, loff_t off, int whence)
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH][UHCI-DEBUG] Don't kmalloc with BKL held
2009-10-03 12:35 ` Sven-Thorsten Dietrich
@ 2009-10-06 7:51 ` Frederik Deweerdt
2009-10-06 10:09 ` Thomas Gleixner
1 sibling, 0 replies; 6+ messages in thread
From: Frederik Deweerdt @ 2009-10-06 7:51 UTC (permalink / raw)
To: Sven-Thorsten Dietrich; +Cc: Frederik Deweerdt, LKML, linux-rt-users
On Sat, Oct 03, 2009 at 05:35:59AM -0700, Sven-Thorsten Dietrich wrote:
> On Fri, 2009-10-02 at 09:20 +0000, Frederik Deweerdt wrote:
> > Hi Sven-Thorsten,
> >
> > On Fri, Oct 02, 2009 at 11:12:24AM +0200, Sven-Thorsten Dietrich wrote:
> > > Subject: Don't kmalloc with BKL held.
> > > From: Sven-Thorsten Dietrich <sdietrich@suse.de>
> > >
> > > I'm eyeballing this file for complete removal of lock_kernel but
> > > at first glance, we definitely don't need BKL to kmalloc().
> > You need to move the unlock_kernel() above the out: label too.
> >
>
> How about this ?
Yes, looks good to me.
>
> Subject: Don't kmalloc with BKL held.
> From: Sven-Thorsten Dietrich sdietrich@suse.de Sat Oct 3 01:27:27 2009 -0700
> Date: Sat Oct 3 01:27:27 2009 -0700:
> Git: 4f62eb81e827eb857129101e49757d84ac9ee7eb
>
> We don't need BKL to kmalloc
>
> diff --git a/drivers/usb/host/uhci-debug.c b/drivers/usb/host/uhci-debug.c
> index e52b954..3fd5602 100644
> --- a/drivers/usb/host/uhci-debug.c
> +++ b/drivers/usb/host/uhci-debug.c
> @@ -494,32 +494,30 @@ static int uhci_debug_open(struct inode *inode, struct file *file)
> {
> struct uhci_hcd *uhci = inode->i_private;
> struct uhci_debug *up;
> - int ret = -ENOMEM;
> unsigned long flags;
>
> - lock_kernel();
> up = kmalloc(sizeof(*up), GFP_KERNEL);
> if (!up)
> - goto out;
> + return -ENOMEM;
>
> up->data = kmalloc(MAX_OUTPUT, GFP_KERNEL);
> if (!up->data) {
> kfree(up);
> - goto out;
> + return -ENOMEM;
> }
>
> up->size = 0;
> +
> + lock_kernel();
> spin_lock_irqsave(&uhci->lock, flags);
> if (uhci->is_initialized)
> up->size = uhci_sprint_schedule(uhci, up->data, MAX_OUTPUT);
> spin_unlock_irqrestore(&uhci->lock, flags);
>
> file->private_data = up;
> -
> - ret = 0;
> -out:
> unlock_kernel();
> - return ret;
> +
> + return 0;
> }
>
> static loff_t uhci_debug_lseek(struct file *file, loff_t off, int whence)
>
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH][UHCI-DEBUG] Don't kmalloc with BKL held
2009-10-03 12:35 ` Sven-Thorsten Dietrich
2009-10-06 7:51 ` Frederik Deweerdt
@ 2009-10-06 10:09 ` Thomas Gleixner
1 sibling, 0 replies; 6+ messages in thread
From: Thomas Gleixner @ 2009-10-06 10:09 UTC (permalink / raw)
To: Sven-Thorsten Dietrich; +Cc: Frederik Deweerdt, LKML, linux-rt-users
On Sat, 3 Oct 2009, Sven-Thorsten Dietrich wrote:
> On Fri, 2009-10-02 at 09:20 +0000, Frederik Deweerdt wrote:
> > Hi Sven-Thorsten,
> >
> > On Fri, Oct 02, 2009 at 11:12:24AM +0200, Sven-Thorsten Dietrich wrote:
> > > Subject: Don't kmalloc with BKL held.
> > > From: Sven-Thorsten Dietrich <sdietrich@suse.de>
> > >
> > > I'm eyeballing this file for complete removal of lock_kernel but
> > > at first glance, we definitely don't need BKL to kmalloc().
> > You need to move the unlock_kernel() above the out: label too.
> >
>
> How about this ?
>
> Subject: Don't kmalloc with BKL held.
> From: Sven-Thorsten Dietrich sdietrich@suse.de Sat Oct 3 01:27:27 2009 -0700
> Date: Sat Oct 3 01:27:27 2009 -0700:
> Git: 4f62eb81e827eb857129101e49757d84ac9ee7eb
>
> We don't need BKL to kmalloc
>
> diff --git a/drivers/usb/host/uhci-debug.c b/drivers/usb/host/uhci-debug.c
> index e52b954..3fd5602 100644
> --- a/drivers/usb/host/uhci-debug.c
> +++ b/drivers/usb/host/uhci-debug.c
> @@ -494,32 +494,30 @@ static int uhci_debug_open(struct inode *inode, struct file *file)
> {
> struct uhci_hcd *uhci = inode->i_private;
> struct uhci_debug *up;
> - int ret = -ENOMEM;
> unsigned long flags;
>
> - lock_kernel();
> up = kmalloc(sizeof(*up), GFP_KERNEL);
> if (!up)
> - goto out;
> + return -ENOMEM;
>
> up->data = kmalloc(MAX_OUTPUT, GFP_KERNEL);
> if (!up->data) {
> kfree(up);
> - goto out;
> + return -ENOMEM;
> }
>
> up->size = 0;
> +
> + lock_kernel();
Why don't you remove it completely ? That lock_kernel() protects
exactly nothing.
Thanks,
tglx
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2009-10-06 10:10 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
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2009-10-02 9:12 [PATCH][UHCI-DEBUG] Don't kmalloc with BKL held Sven-Thorsten Dietrich
2009-10-02 9:20 ` Frederik Deweerdt
2009-10-03 12:35 ` Sven-Thorsten Dietrich
2009-10-06 7:51 ` Frederik Deweerdt
2009-10-06 10:09 ` Thomas Gleixner
2009-10-02 12:01 ` Oliver Neukum
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