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x86, bts, mm: clean up buffer allocation

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The current mm interface is asymetric. One function allocates a locked
buffer, another function only refunds the memory.

Change this to have two functions for accounting and refunding locked
memory, respectively; and do the actual buffer allocation in ptrace.

[ Impact: refactor BTS buffer allocation code ]

Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20090424095143.A30265@sedona.ch.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Markus Metzger
2009-04-24 09:51:43 +02:00
committed by Ingo Molnar
parent 7e0bfad24d
commit 1cb81b143f
3 changed files with 47 additions and 34 deletions
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39
arch/x86/kernel/ptrace.c
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@@ -617,17 +617,28 @@ struct bts_context {
struct work_struct work;
};
static inline void alloc_bts_buffer(struct bts_context *context,
unsigned int size)
static int alloc_bts_buffer(struct bts_context *context, unsigned int size)
{
void *buffer;
void *buffer = NULL;
int err = -ENOMEM;
buffer = alloc_locked_buffer(size);
if (buffer) {
context->buffer = buffer;
context->size = size;
context->mm = get_task_mm(current);
}
err = account_locked_memory(current->mm, current->signal->rlim, size);
if (err < 0)
return err;
buffer = kzalloc(size, GFP_KERNEL);
if (!buffer)
goto out_refund;
context->buffer = buffer;
context->size = size;
context->mm = get_task_mm(current);
return 0;
out_refund:
refund_locked_memory(current->mm, size);
return err;
}
static inline void free_bts_buffer(struct bts_context *context)
@@ -638,7 +649,7 @@ static inline void free_bts_buffer(struct bts_context *context)
kfree(context->buffer);
context->buffer = NULL;
refund_locked_buffer_memory(context->mm, context->size);
refund_locked_memory(context->mm, context->size);
context->size = 0;
mmput(context->mm);
@@ -786,13 +797,15 @@ static int ptrace_bts_config(struct task_struct *child,
context->tracer = NULL;
if ((cfg.flags & PTRACE_BTS_O_ALLOC) && (cfg.size != context->size)) {
int err;
free_bts_buffer(context);
if (!cfg.size)
return 0;
alloc_bts_buffer(context, cfg.size);
if (!context->buffer)
return -ENOMEM;
err = alloc_bts_buffer(context, cfg.size);
if (err < 0)
return err;
}
if (cfg.flags & PTRACE_BTS_O_TRACE)