From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <48F1D15F.3010902@domain.hid>
Date: Sun, 12 Oct 2008 12:28:47 +0200
From: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Subject: [Xenomai-core] Comedi buffer management.
List-Id: "Xenomai life and development \(bug reports, patches,
	discussions\)" <xenomai.xenomai.org>
List-Unsubscribe: <https://mail.gna.org/listinfo/xenomai-core>,
	<mailto:xenomai-core-request@domain.hid>
List-Archive: </public/xenomai-core>
List-Post: <mailto:xenomai@xenomai.org>
List-Help: <mailto:xenomai-core-request@domain.hid>
List-Subscribe: <https://mail.gna.org/listinfo/xenomai-core>,
	<mailto:xenomai-core-request@domain.hid>
To: Alexis Berlemont <berlemont.hauw@domain.hid>
Cc: Xenomai core <Xenomai-core@domain.hid>


Hi Alex,

I commited in trunk a fix of Xenomai heap management for the highmem 
case. What the patch does is essentially replacing __va_to_kva (which 
does not work correctly with highmem) with vmalloc_to_page, which is 
available on all linux versions Xenomai supports.

However, I found that comedi buffer management also uses __va_to_kva. We 
can fix SetPageReserved and ClearPageReserved easily to use 
vmalloc_to_page, however, I do not see what pg_list is used for, so do 
not really know how to fix it. Here is a proposed patch:

Index: ksrc/drivers/comedi/buffer.c
===================================================================
--- ksrc/drivers/comedi/buffer.c	(revision 4211)
+++ ksrc/drivers/comedi/buffer.c	(working copy)
@@ -46,7 +46,7 @@ void comedi_free_buffer(comedi_buf_t * b
 		unsigned long vaddr, vabase = (unsigned long)buf_desc->buf;
 		for (vaddr = vabase; vaddr < vabase + buf_desc->size;
 		     vaddr += PAGE_SIZE)
-			ClearPageReserved(virt_to_page(__va_to_kva(vaddr)));
+			ClearPageReserved(vmalloc_to_page(vaddr));
 		vfree(buf_desc->buf);
 		buf_desc->buf = NULL;
 	}
@@ -73,7 +73,7 @@ int comedi_alloc_buffer(comedi_buf_t * b
 
 	for (vaddr = vabase; vaddr < vabase + buf_desc->size;
 	     vaddr += PAGE_SIZE)
-		SetPageReserved(virt_to_page(__va_to_kva(vaddr)));
+		SetPageReserved(vmalloc_to_page(vaddr));
 
 	buf_desc->pg_list = comedi_kmalloc(((buf_desc->size) >> PAGE_SHIFT) *
 					   sizeof(unsigned long));
@@ -85,7 +85,7 @@ int comedi_alloc_buffer(comedi_buf_t * b
 	for (vaddr = vabase; vaddr < vabase + buf_desc->size;
 	     vaddr += PAGE_SIZE)
 		buf_desc->pg_list[(vaddr - vabase) >> PAGE_SHIFT] =
-		    __va_to_kva(vaddr);
+			(unsigned long) vmalloc_to_page(vaddr);
 
       out_virt_contig_alloc:
 	if (ret != 0)

Cheers.

-- 
					    Gilles.