[ofw] Patch: Replace memory allocator with a memory allocator that works natively with 0 bytes allocations

[Tzachi Dar]

Here is a new and much smaller version of the patch that does not introduce new functions or new abstractions. It also only touches a very small number of places.

I hope this time it is OK.

Index: core/complib/kernel/cl_memory_osd.c
===================================================================
--- core/complib/kernel/cl_memory_osd.c	(revision 2933)
+++ core/complib/kernel/cl_memory_osd.c	(working copy)
@@ -38,6 +38,10 @@
 	IN	const size_t	size,
 	IN	const boolean_t	pageable )
 {
+	CL_ASSERT(size != 0);
+	if (size ==0) {
+		return NULL;
+	}
 	if( pageable )
 	{
 		CL_ASSERT( KeGetCurrentIrql() < DISPATCH_LEVEL );
Index: hw/mthca/kernel/mt_memory.h
===================================================================
--- hw/mthca/kernel/mt_memory.h	(revision 2933)
+++ hw/mthca/kernel/mt_memory.h	(working copy)
@@ -50,6 +50,10 @@
 {
 	void *ptr;
 	MT_ASSERT( KeGetCurrentIrql() <= DISPATCH_LEVEL );
+	MT_ASSERT(bsize);
+	if(bsize == 0) {
+		return NULL;
+	}
 	switch (gfp_mask) {
 		case GFP_ATOMIC:
 			ptr = ExAllocatePoolWithTag( NonPagedPool, bsize, MT_TAG_ATOMIC );


Thanks
Tzachi

> -----Original Message-----
> From: Hefty, Sean [mailto:sean.hefty at intel.com]
> Sent: Tuesday, August 31, 2010 7:31 PM
> To: Tzachi Dar; ofw at lists.openfabrics.org
> Subject: RE: [ofw] Patch: Replace memory allocator with a memory
> allocator that works natively with 0 bytes allocations
> 
> There are several unrelated changes in this patch, and I personally
> still don't like the idea.  First, it adds overhead that's not needed
> in most cases.  Second, it uses a function name that looks like a
> Windows call, but isn't.  Someone reading the code has to discover that
> the call is some macro.  And in order to make this change, you already
> have to look at and touch everywhere that the size could be 0.  Why not
> just fix those places already?
> 
> There is already WAY too much abstraction in the code base.  Adding
> more does not fix things, it only makes it worse.  This can end up
> hiding bugs.  Upper level code should not work around problems in other
> code, especially drivers.