WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-ppc-devel

[Xen-devel] [patch] grant_entry.flags accessors

To: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Subject: [Xen-devel] [patch] grant_entry.flags accessors
From: Hollis Blanchard <hollisb@xxxxxxxxxx>
Date: Thu, 29 Jun 2006 16:19:11 -0500
Cc: xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>, xen-ppc-devel <xen-ppc-devel@xxxxxxxxxxxxxxxxxxx>
Delivery-date: Thu, 29 Jun 2006 14:19:14 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <1151097564.14454.44.camel@xxxxxxxxxxxxxxxxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
Organization: IBM Linux Technology Center
References: <1151097564.14454.44.camel@xxxxxxxxxxxxxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Hi Keir, here is the resend based on your feedback. The Linux patch
applies with small offsets to the sparse tree. The Xen patch follows
that.

Use explicit accessors to handle unusually-sized atomic operations in
grant table code.
Signed-off-by: Hollis Blanchard <hollisb@xxxxxxxxxx>

diff -r 6f3d44537b76 drivers/xen/core/gnttab.c
--- a/drivers/xen/core/gnttab.c Fri Jun 16 16:07:38 2006 -0500
+++ b/drivers/xen/core/gnttab.c Fri Jun 23 15:57:39 2006 -0500
@@ -201,7 +201,7 @@ gnttab_end_foreign_access_ref(grant_ref_
                        printk(KERN_ALERT "WARNING: g.e. still in use!\n");
                        return 0;
                }
-       } while ((nflags = synch_cmpxchg(&shared[ref].flags, flags, 0)) !=
+       } while ((nflags = synch_cmpxchg_subword(&shared[ref].flags, flags, 0)) 
!=
                 flags);
 
        return 1;
@@ -256,7 +256,7 @@ gnttab_end_foreign_transfer_ref(grant_re
          * reference and return failure (== 0).
          */
        while (!((flags = shared[ref].flags) & GTF_transfer_committed)) {
-               if (synch_cmpxchg(&shared[ref].flags, flags, 0) == flags)
+               if (synch_cmpxchg_subword(&shared[ref].flags, flags, 0) == 
flags)
                        return 0;
                cpu_relax();
        }
diff -r 6f3d44537b76 include/asm-i386/mach-xen/asm/synch_bitops.h
--- a/include/asm-i386/mach-xen/asm/synch_bitops.h      Fri Jun 16 16:07:38 
2006 -0500
+++ b/include/asm-i386/mach-xen/asm/synch_bitops.h      Fri Jun 23 15:57:39 
2006 -0500
@@ -138,4 +138,6 @@ static __inline__ int synch_var_test_bit
  synch_const_test_bit((nr),(addr)) : \
  synch_var_test_bit((nr),(addr)))
 
+#define synch_cmpxchg_subword synch_cmpxchg
+
 #endif /* __XEN_SYNCH_BITOPS_H__ */
diff -r 6f3d44537b76 include/asm-ia64/synch_bitops.h
--- a/include/asm-ia64/synch_bitops.h   Fri Jun 16 16:07:38 2006 -0500
+++ b/include/asm-ia64/synch_bitops.h   Fri Jun 23 15:57:39 2006 -0500
@@ -58,4 +58,6 @@ static __inline__ int synch_var_test_bit
  synch_const_test_bit((nr),(addr)) : \
  synch_var_test_bit((nr),(addr)))
 
+#define synch_cmpxchg_subword synch_cmpxchg
+
 #endif /* __XEN_SYNCH_BITOPS_H__ */

The Xen patch:

diff -r e06866a6e2b7 xen/common/grant_table.c
--- a/xen/common/grant_table.c  Thu Jun 29 13:10:42 2006 -0400
+++ b/xen/common/grant_table.c  Thu Jun 29 15:27:06 2006 -0500
@@ -287,10 +287,10 @@ __gnttab_map_grant_ref(
 
     if ( !(op->flags & GNTMAP_readonly) &&
          !(act->pin & (GNTPIN_hstw_mask|GNTPIN_devw_mask)) )
-        clear_bit(_GTF_writing, &sha->flags);
+        gnttab_clear_flag(_GTF_writing, &sha->flags);
 
     if ( !act->pin )
-        clear_bit(_GTF_reading, &sha->flags);
+        gnttab_clear_flag(_GTF_reading, &sha->flags);
 
  unlock_out:
     spin_unlock(&rd->grant_table->lock);
@@ -425,10 +425,10 @@ __gnttab_unmap_grant_ref(
 
     if ( ((act->pin & (GNTPIN_devw_mask|GNTPIN_hstw_mask)) == 0) &&
          !(flags & GNTMAP_readonly) )
-        clear_bit(_GTF_writing, &sha->flags);
+        gnttab_clear_flag(_GTF_writing, &sha->flags);
 
     if ( act->pin == 0 )
-        clear_bit(_GTF_reading, &sha->flags);
+        gnttab_clear_flag(_GTF_reading, &sha->flags);
 
  unmap_out:
     op->status = rc;
@@ -889,11 +889,11 @@ gnttab_release_mappings(
             }
 
             if ( (act->pin & (GNTPIN_devw_mask|GNTPIN_hstw_mask)) == 0 )
-                clear_bit(_GTF_writing, &sha->flags);
+                gnttab_clear_flag(_GTF_writing, &sha->flags);
         }
 
         if ( act->pin == 0 )
-            clear_bit(_GTF_reading, &sha->flags);
+            gnttab_clear_flag(_GTF_reading, &sha->flags);
 
         spin_unlock(&rd->grant_table->lock);
 
diff -r e06866a6e2b7 xen/include/asm-ia64/grant_table.h
--- a/xen/include/asm-ia64/grant_table.h        Thu Jun 29 13:10:42 2006 -0400
+++ b/xen/include/asm-ia64/grant_table.h        Thu Jun 29 15:27:06 2006 -0500
@@ -55,4 +55,9 @@ void guest_physmap_add_page(struct domai
 
 #define gnttab_log_dirty(d, f) ((void)0)
 
+static inline void gnttab_clear_flag(unsigned long nr, uint16_t *addr)
+{
+       clear_bit(nr, addr);
+}
+
 #endif /* __ASM_GRANT_TABLE_H__ */
diff -r e06866a6e2b7 xen/include/asm-x86/grant_table.h
--- a/xen/include/asm-x86/grant_table.h Thu Jun 29 13:10:42 2006 -0400
+++ b/xen/include/asm-x86/grant_table.h Thu Jun 29 15:27:06 2006 -0500
@@ -33,4 +33,9 @@ int destroy_grant_host_mapping(
 
 #define gnttab_log_dirty(d, f) mark_dirty((d), (f))
 
+static inline void gnttab_clear_flag(unsigned long nr, uint16_t *addr)
+{
+       clear_bit(nr, addr);
+}
+
 #endif /* __ASM_GRANT_TABLE_H__ */



-- 
Hollis Blanchard
IBM Linux Technology Center


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel