[Xenomai-core] [PATCH v3 2/9] nucleus: Use Linux spin lock for heap list management

[Jan Kiszka]

No need for hard nklock protection of kheapq and the map counter, a
normal spin lock suffices as all users must run over the root thread
anyway.

Signed-off-by: Jan Kiszka <jan.kis...@siemens.com>
---

 ksrc/nucleus/heap.c |   26 ++++++++++++--------------
 1 files changed, 12 insertions(+), 14 deletions(-)

diff --git a/ksrc/nucleus/heap.c b/ksrc/nucleus/heap.c
index 9ca2591..9ba5227 100644
--- a/ksrc/nucleus/heap.c
+++ b/ksrc/nucleus/heap.c
@@ -951,8 +951,10 @@ EXPORT_SYMBOL_GPL(xnheap_check_block);
 #include <linux/device.h>
 #include <linux/vmalloc.h>
 #include <linux/mm.h>
+#include <linux/spinlock.h>
 
 static DEFINE_XNQUEUE(kheapq); /* Shared heap queue. */
+static DEFINE_SPINLOCK(kheapq_lock);
 
 static inline void *__alloc_and_reserve_heap(size_t size, int kmflags)
 {
@@ -1022,14 +1024,13 @@ static void __unreserve_and_free_heap(void *ptr, size_t 
size, int kmflags)
 static void xnheap_vmclose(struct vm_area_struct *vma)
 {
        xnheap_t *heap = vma->vm_private_data;
-       spl_t s;
 
-       xnlock_get_irqsave(&nklock, s);
+       spin_lock(&kheapq_lock);
 
        if (atomic_dec_and_test(&heap->archdep.numaps)) {
                if (heap->archdep.release) {
                        removeq(&kheapq, &heap->link);
-                       xnlock_put_irqrestore(&nklock, s);
+                       spin_unlock(&kheapq_lock);
                        __unreserve_and_free_heap(heap->archdep.heapbase,
                                                  xnheap_extentsize(heap),
                                                  heap->archdep.kmflags);
@@ -1038,7 +1039,7 @@ static void xnheap_vmclose(struct vm_area_struct *vma)
                }
        }
 
-       xnlock_put_irqrestore(&nklock, s);
+       spin_unlock(&kheapq_lock);
 }
 
 static struct vm_operations_struct xnheap_vmops = {
@@ -1068,9 +1069,8 @@ static int xnheap_ioctl(struct inode *inode,
 {
        xnheap_t *heap;
        int err = 0;
-       spl_t s;
 
-       xnlock_get_irqsave(&nklock, s);
+       spin_lock(&kheapq_lock);
 
        heap = __validate_heap_addr((void *)arg);
 
@@ -1083,7 +1083,7 @@ static int xnheap_ioctl(struct inode *inode,
 
       unlock_and_exit:
 
-       xnlock_put_irqrestore(&nklock, s);
+       spin_unlock(&kheapq_lock);
 
        return err;
 }
@@ -1148,7 +1148,6 @@ static int xnheap_mmap(struct file *file, struct 
vm_area_struct *vma)
 int xnheap_init_mapped(xnheap_t *heap, u_long heapsize, int memflags)
 {
        void *heapbase;
-       spl_t s;
        int err;
 
        /* Caller must have accounted for internal overhead. */
@@ -1172,9 +1171,9 @@ int xnheap_init_mapped(xnheap_t *heap, u_long heapsize, 
int memflags)
        heap->archdep.heapbase = heapbase;
        heap->archdep.release = NULL;
 
-       xnlock_get_irqsave(&nklock, s);
+       spin_lock(&kheapq_lock);
        appendq(&kheapq, &heap->link);
-       xnlock_put_irqrestore(&nklock, s);
+       spin_unlock(&kheapq_lock);
 
        return 0;
 }
@@ -1184,20 +1183,19 @@ int xnheap_destroy_mapped(xnheap_t *heap, void 
(*release)(struct xnheap *heap),
 {
        int ret = 0, ccheck;
        unsigned long len;
-       spl_t s;
 
        ccheck = mapaddr ? 1 : 0;
 
-       xnlock_get_irqsave(&nklock, s);
+       spin_lock(&kheapq_lock);
 
        if (atomic_read(&heap->archdep.numaps) > ccheck) {
                heap->archdep.release = release;
-               xnlock_put_irqrestore(&nklock, s);
+               spin_unlock(&kheapq_lock);
                return -EBUSY;
        }
 
        removeq(&kheapq, &heap->link); /* Prevent further mapping. */
-       xnlock_put_irqrestore(&nklock, s);
+       spin_unlock(&kheapq_lock);
 
        len = xnheap_extentsize(heap);
 


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