> I got tired of the problems with the resource management - lack of
> hierarchy, and the stupid and utterly horrible static allocation.
>
> So I rewrote it.
> ...
> The old "request_region()" thing still works, but not until after the
> memory allocator has been initialized (because it uses kmalloc()). So
> stuff that does resource allocation early during boot has to actually use
> "struct resource" directly - normal device drivers can just ignore the
> change.
2.3.11-pre1 works fine here, but I noticed two problems:
1. The legacy support stuff leaks memory. Both request_region()
and check_region() will kmalloc resource structs which are
never kfree'd.
The patch below fixes this by adding a kfree() to __check_region(),
having __request_region() set a flag RSRC_AUTOFREE in the
resource struct, and letting __release_region() kfree the
struct if this flag is set. This way, legacy drivers will
continue to work without leaking memory.
2. drivers/video/vgacon.c calls request_region() before the
slab allocator and kmalloc are initialised, causing request_region
to silently fail and a "NULL ptr" message in the kernel log.
The patch below fixes this (for vgacon only) by transparently
translating its request_region() calls to request_resource()
calls with static parameters. (The patch (ab)uses the pre-
processor. I kind of like it, but others may find it gross.)
/Mikael
--- linux-2.3.11-pre1/kernel/resource.c.~1~ Sat Jul 10 13:44:02 1999
+++ linux-2.3.11-pre1/kernel/resource.c Sat Jul 10 17:54:20 1999
@@ -13,7 +13,7 @@
#include <linux/malloc.h>
struct resource pci_io_resource = { "PCI IO", 0x0000, 0xFFFF };
-struct resource pci_mem_resource = { "PCI mem", 0x00000000, 0xFFFFFFFF };
+struct resource pci_mem_resource = { "PCI mem", 0x00000000, 0xFFFFFFFF };
/*
* This generates reports for /proc/ioports and /proc/memory
@@ -101,7 +101,7 @@
return -EINVAL;
}
-struct resource * __request_region(struct resource *parent, unsigned long start, unsigned long n, const char *name)
+struct resource * __request_region(struct resource *parent, unsigned long start, unsigned long n, const char *name, unsigned long flags)
{
struct resource *res = kmalloc(sizeof(*res), GFP_KERNEL);
@@ -110,6 +110,7 @@
res->name = name;
res->start = start;
res->end = start + n - 1;
+ res->flags = flags;
if (request_resource(parent, res) != 0) {
kfree(res);
res = NULL;
@@ -130,11 +131,12 @@
{
struct resource * res;
- res = __request_region(parent, start, n, "check-region");
+ res = __request_region(parent, start, n, "check-region", 0);
if (!res)
return -EBUSY;
release_resource(res);
+ kfree(res);
return 0;
}
@@ -153,6 +155,8 @@
break;
if (tmp->start == start && tmp->end == end) {
*p = tmp->sibling;
+ if (tmp->flags & RSRC_AUTOFREE)
+ kfree(tmp);
break;
}
p = &tmp->sibling;
--- linux-2.3.11-pre1/include/linux/ioport.h.~1~ Sat Jul 10 13:44:01 1999
+++ linux-2.3.11-pre1/include/linux/ioport.h Sat Jul 10 17:44:59 1999
@@ -18,6 +18,7 @@
unsigned long flags;
struct resource *parent, *sibling, *child;
};
+#define RSRC_AUTOFREE 0x80000000 /* __release_region() will free resource */
extern struct resource pci_io_resource;
extern struct resource pci_mem_resource;
@@ -29,11 +30,11 @@
extern int release_resource(struct resource *new);
/* Convenience shorthand with allocation */
-#define request_region(start,n,name) __request_region(&pci_io_resource, (start), (n), (name))
-extern struct resource * __request_region(struct resource *, unsigned long start, unsigned long n, const char *name);
+extern struct resource * __request_region(struct resource *, unsigned long start, unsigned long n, const char *name, unsigned long flags);
-/* Compatibility cruft */
+/* Compatibility cruft with automatic allocation and deallocation */
#define check_region(start,n) __check_region(&pci_io_resource, (start), (n))
+#define request_region(start,n,name) (void)__request_region(&pci_io_resource, (start), (n), (name), RSRC_AUTOFREE)
#define release_region(start,n) __release_region(&pci_io_resource, (start), (n))
extern int __check_region(struct resource *, unsigned long, unsigned long);
extern void __release_region(struct resource *, unsigned long, unsigned long);
--- linux-2.3.11-pre1/drivers/video/vgacon.c.~1~ Mon Jun 21 20:45:46 1999
+++ linux-2.3.11-pre1/drivers/video/vgacon.c Sat Jul 10 17:57:06 1999
@@ -115,6 +115,16 @@
static int vga_video_font_height;
static unsigned int vga_rolled_over = 0;
+/* vgacon is initialised before kmalloc() is, so request_region()
+ * doesn't work. This macro translates vgacon's request_region()
+ * calls to equivalent request_resource() calls.
+ */
+#undef request_region
+#define request_region(start,n,name) \
+do { \
+ static struct resource region = { name, start, start+n-1 }; \
+ (void) request_resource(&pci_io_resource, ®ion); \
+} while(0)
void no_scroll(char *str, int *ints)
{
-
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