Hi,

Stefan Kisdaroczi wrote:
Hi all,

as a reminder (userspace, native skin, shared heap) [1]:
API documentation: "If the heap is shared, this value can be either zero, or the same value given to rt_heap_create()." This is not true. As the heapsize gets altered in rt_heap_create for page size alignment, the following call to rt_heap_alloc with the same value will fail.

Ex:
rt_heap_create( ..., ..., 10000, ... )
rt_heap_alloc( ..., 10000, ..., .... ) -> This call fails

I suggest only accepting zero as a valid size for shared heaps.

about attached patch:
1) not tested
2) there are possible better names than H_ALL
3) the comments could be in a better english
4) i hope you get the idea


The heap support is currently reworked in the native API so that we can access it from user-space without necessarily asking for a single common block, to obtain a shared memory segment, like in the present situation (i.e. the H_ALL mode in your patch). The idea is to decouple the mappable and single-block properties of heaps. Therefore, your patch is actually going to be a subset of this larger update. Thanks for your contribution to this.

thx
kisda

[1] https://mail.gna.org/public/xenomai-core/2006-01/msg00177.html


------------------------------------------------------------------------

Index: include/native/heap.h
===================================================================
--- include/native/heap.h       (Revision 465)
+++ include/native/heap.h       (Arbeitskopie)
@@ -32,6 +32,9 @@
 #define H_DMA    0x100         /* Use memory suitable for DMA. */
 #define H_SHARED 0x200         /* Use mappable shared memory. */
+/* Operation flags. */
+#define H_ALL    0x0           /* Entire heap space. */
+
 typedef struct rt_heap_info {
int nwaiters; /* !< Number of pending tasks. */
Index: ksrc/skins/native/heap.c
===================================================================
--- ksrc/skins/native/heap.c    (Revision 465)
+++ ksrc/skins/native/heap.c    (Arbeitskopie)
@@ -410,10 +410,9 @@
  * from.
  *
  * @param size The requested size in bytes of the block. If the heap
- * is shared, this value can be either zero, or the same value given
- * to rt_heap_create(). In any case, the same block covering the
- * entire heap space will always be returned to all callers of this
- * service.
+ * is shared, H_ALL should be passed, as always the same block
+ * covering the entire heap space will be returned to all callers of
+ * this service.
  *
  * @param timeout The number of clock ticks to wait for a block of
  * sufficient size to be available from a local heap (see
@@ -432,8 +431,7 @@
  * @return 0 is returned upon success. Otherwise:
  *
  * - -EINVAL is returned if @a heap is not a heap descriptor, or @a
- * heap is shared (i.e. H_SHARED mode) and @a size is non-zero but
- * does not match the actual heap size passed to rt_heap_create().
+ * heap is shared (i.e. H_SHARED mode) and @a size is not H_ALL.
  *
  * - -EIDRM is returned if @a heap is a deleted heap descriptor.
  *
@@ -503,12 +501,7 @@
if (!block)
            {
-           /* It's ok to pass zero for size here, since the requested
-              size is implicitely the whole heap space; but if
-              non-zero is given, it must match the actual heap
-              size. */
-
-           if (size > 0 && size != xnheap_size(&heap->heap_base))
+           if (size != H_ALL)
                {
                err = -EINVAL;
                goto unlock_and_exit;


------------------------------------------------------------------------

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--

Philippe.

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