linux-kernel - RE: [PATCH] ACPI - change GFP_ATOMIC to GFP

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Date:	Sun, 23 Jul 2006 16:20:44 +0200 (CEST)
From:	Jiri Kosina <jikos@...os.cz>
To:	"Brown, Len" <len.brown@...el.com>
cc:	linux-acpi <linux-acpi@...el.com>, linux-kernel@...r.kernel.org
Subject: RE: [PATCH] ACPI - change GFP_ATOMIC to GFP_KERNEL for non-atomic
 allocation

On Sat, 22 Jul 2006, Brown, Len wrote:

> > drivers/acpi/pci_link.c::acpi_pci_link_set() sets the GFP_ATOMIC for
> > kmalloc() allocation for no first-sight obvious reason; as far as I
> > can see this is always called outside the atomic/interrupt context, so
> > GFP_KERNEL allocation should be used instead.
> this would oops on a resume from suspend -- when it is called with
> interrupts off.

But in such a case I guess the following callchain has a problem:

acpi_pci_link_resume -> acpi_pci_link_set -> acpi_set_current_resources ->
acpi_rs_set_srs_method_data -> acpi_ut_create_internal_object_dbg ->
acpi_ut_allocate_object_desc_dbg -> acpi_os_acquire_object ->
kmem_cache_alloc with GFP_KERNEL flag.

What about the following patch to handle both cases without oopsing? (I am 
not using the acpi_in_resume flag, as it is makred for removal)


Signed-off-by: Jiri Kosina <jikos@...os.cz>

--- drivers/acpi/osl.c.orig	2006-07-15 21:00:43.000000000 +0200
+++ drivers/acpi/osl.c	2006-07-23 16:03:08.000000000 +0200
@@ -1141,7 +1141,13 @@ acpi_status acpi_os_release_object(acpi_
 
 void *acpi_os_acquire_object(acpi_cache_t * cache)
 {
-	void *object = kmem_cache_alloc(cache, GFP_KERNEL);
+	void *object;
+
+	/* irqs could be disabled when resuming from suspend */
+	if (irqs_disabled())
+		object = kmem_cache_alloc(cache, GFP_ATOMIC);
+	else
+		object = kmem_cache_alloc(cache, GFP_KERNEL);
 	WARN_ON(!object);
 	return object;
 }
--- drivers/acpi/pci_link.c.orig	2006-07-15 21:00:43.000000000 +0200
+++ drivers/acpi/pci_link.c	2006-07-23 16:01:42.000000000 +0200
@@ -318,7 +318,12 @@ static int acpi_pci_link_set(struct acpi
 	if (!link || !irq)
 		return_VALUE(-EINVAL);
 
-	resource = kmalloc(sizeof(*resource) + 1, GFP_ATOMIC);
+	/* irqs could be disabled when resuming from suspend */
+	if (irqs_disabled())
+		resource = kmalloc(sizeof(*resource) + 1, GFP_ATOMIC);
+	else
+		resource = kmalloc(sizeof(*resource) + 1, GFP_KERNEL);
+	
 	if (!resource)
 		return_VALUE(-ENOMEM);
 

-- 
JiKos.
-
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