Re: [PATCH] adjust/fix LDT handling for Xen
From: Jiri Slaby
Date: Fri Jan 11 2008 - 04:39:52 EST
On 01/11/2008 10:22 AM, Jan Beulich wrote:
Don't rely on kmalloc(PAGE_SIZE) returning PAGE_SIZE aligned memory
(Xen requires GDT *and* LDT to be page-aligned). Using the page
allocator interface also removes the (albeit small) slab allocator
overhead. The same change being done for 64-bits for consistency.
Further, the Xen hypercall interface expects the LDT address to be
virtual, not machine.
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
---
arch/x86/kernel/ldt_32.c | 7 +++----
arch/x86/kernel/ldt_64.c | 7 +++----
arch/x86/xen/enlighten.c | 9 +--------
3 files changed, 7 insertions(+), 16 deletions(-)
--- linux-2.6.24-rc7/arch/x86/kernel/ldt_32.c 2008-01-10 16:53:54.000000000 +0100
+++ 2.6.24-rc7-x86-xen-ldt/arch/x86/kernel/ldt_32.c 2008-01-09 13:59:50.000000000 +0100
[...]
@@ -73,7 +72,7 @@ static int alloc_ldt(mm_context_t *pc, u
if (oldsize*LDT_ENTRY_SIZE > PAGE_SIZE)
vfree(oldldt);
else
- kfree(oldldt);
+ put_page(virt_to_page(oldldt));
}
return 0;
}
@@ -117,7 +116,7 @@ void destroy_context(struct mm_struct *m
if ((unsigned)mm->context.size*LDT_ENTRY_SIZE > PAGE_SIZE)
vfree(mm->context.ldt);
else
- kfree(mm->context.ldt);
+ put_page(virt_to_page(mm->context.ldt));
why not free_page() with all those checks if it is correct virt address which it
brings?
regards,
--
Jiri Slaby
Faculty of Informatics, Masaryk University
Suse Labs
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