[PATCH 1/3] Do not use DEFINE_RWLOCK Macro

[PATCH 1/3] Do not use DEFINE_RWLOCK Macro

[Ben Guthro]

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Do not use the DEFINE_RWLOCK macro, as it is not available when compiled 
against
older kernels, such as SLES9's 2.6.5

Signed-off-by: Ben Guthro <bguthro@virtualron.com>

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[-- Type: text/x-patch, Size: 733 bytes --]

diff -r ef25e071a074 unmodified_drivers/linux-2.6/platform-pci/machine_reboot.c
--- a/unmodified_drivers/linux-2.6/platform-pci/machine_reboot.c	Wed Aug 29 13:38:54 2007 -0400
+++ b/unmodified_drivers/linux-2.6/platform-pci/machine_reboot.c	Wed Aug 29 13:41:20 2007 -0400
@@ -15,8 +15,10 @@ struct ap_suspend_info {
 /*
  * Use a rwlock to protect the hypercall page from being executed in AP context
  * while the BSP is re-initializing it after restore.
+ * Do not use the DEFINE_RWLOCK macro, as it is not available when compiled against
+ *  older kernels
  */
-static DEFINE_RWLOCK(suspend_lock);
+static rwlock_t suspend_lock = RW_LOCK_UNLOCKED;
 
 /*
  * Spinning prevents, for example, APs touching grant table entries while

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Re: [PATCH 1/3] Do not use DEFINE_RWLOCK Macro

[Ian Campbell]

On Wed, 2007-08-29 at 14:20 -0400, Ben Guthro wrote:
> Do not use the DEFINE_RWLOCK macro, as it is not available when compiled 
> against older kernels, such as SLES9's 2.6.5

Things like this should generally be done by adding a suitably guarded
definition of DEFINE_RWLOCK to the platform-compat.h header in
unmodified_drivers/linux-2.6/compat-include/xen/platform-compat.h.

Ian.

Re: [PATCH 1/3] Do not use DEFINE_RWLOCK Macro

[Ben Guthro]

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Revised patch attached.

Note that I did run into a problem with a buggy kernel in RHEL4-U3.
It seems that in this macro, rw_lock_t was used instead of rwlock_t. I 
added a line to platform-compat.h to account for this.

Ben

Signed-off-by: Ben Guthro <bguthro@virtualiron.com>


Ian Campbell wrote:
> On Wed, 2007-08-29 at 14:20 -0400, Ben Guthro wrote:
>   
>> Do not use the DEFINE_RWLOCK macro, as it is not available when compiled 
>> against older kernels, such as SLES9's 2.6.5
>>     
>
> Things like this should generally be done by adding a suitably guarded
> definition of DEFINE_RWLOCK to the platform-compat.h header in
> unmodified_drivers/linux-2.6/compat-include/xen/platform-compat.h.
>
> Ian.
>
>   


[-- Attachment #2: xen-legacy-reboot.patch --]
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diff -r a381118a247a unmodified_drivers/linux-2.6/compat-include/xen/platform-compat.h
--- a/unmodified_drivers/linux-2.6/compat-include/xen/platform-compat.h	Wed Aug 29 15:30:40 2007 -0400
+++ b/unmodified_drivers/linux-2.6/compat-include/xen/platform-compat.h	Wed Aug 29 16:26:33 2007 -0400
@@ -116,4 +116,13 @@ extern char *kasprintf(gfp_t gfp, const 
 #define DEFINE_SEQLOCK(x) seqlock_t x = SEQLOCK_UNLOCKED
 #endif
 
+#if defined(__LINUX_SPINLOCK_H) && !defined(DEFINE_RWLOCK)
+#define DEFINE_RWLOCK(x) rwlock_t x = RW_LOCK_UNLOCKED
 #endif
+
+/* Bug in RHEL4-U3 rw_lock_t is mistakenly defined in this macro */
+#if defined(__LINUX_SPINLOCK_H) && defined(DEFINE_RWLOCK)
+#define rw_lock_t rwlock_t
+#endif
+
+#endif

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