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Subject[PATCH 8/9] ARC: mm: do_page_fault refactor #7: fold the various error handling
Date
 - single up_read() call vs. 4
- so much easier on eyes

Technically it seems like @bad_area label moved up, but even in old
regime, it was a special case of delivering SIGSEGV unconditionally
which we now do as well, although with checks.

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
---
arch/arc/mm/fault.c | 46 +++++++++++++---------------------------------
1 file changed, 13 insertions(+), 33 deletions(-)

diff --git a/arch/arc/mm/fault.c b/arch/arc/mm/fault.c
index 0e1a222a97ad..20402217d9da 100644
--- a/arch/arc/mm/fault.c
+++ b/arch/arc/mm/fault.c
@@ -66,7 +66,7 @@ void do_page_fault(unsigned long address, struct pt_regs *regs)
struct vm_area_struct *vma = NULL;
struct task_struct *tsk = current;
struct mm_struct *mm = tsk->mm;
- int si_code = SEGV_MAPERR;
+ int sig, si_code = SEGV_MAPERR;
unsigned int write = 0, exec = 0, mask;
vm_fault_t fault; /* handle_mm_fault() output */
unsigned int flags; /* handle_mm_fault() input */
@@ -177,47 +177,27 @@ void do_page_fault(unsigned long address, struct pt_regs *regs)
return;
}

- if (fault & VM_FAULT_OOM)
- goto out_of_memory;
- else if (fault & VM_FAULT_SIGSEGV)
- goto bad_area;
- else if (fault & VM_FAULT_SIGBUS)
- goto do_sigbus;
-
- /* no man's land */
- BUG();
-
- /*
- * Something tried to access memory that isn't in our memory map..
- * Fix it, but check if it's kernel or user first..
- */
bad_area:
up_read(&mm->mmap_sem);

if (!user_mode(regs))
goto no_context;

- tsk->thread.fault_address = address;
- force_sig_fault(SIGSEGV, si_code, (void __user *)address, tsk);
- return;
-
-out_of_memory:
- up_read(&mm->mmap_sem);
-
- if (!user_mode(regs))
- goto no_context;
-
- pagefault_out_of_memory();
- return;
-
-do_sigbus:
- up_read(&mm->mmap_sem);
+ if (fault & VM_FAULT_OOM) {
+ pagefault_out_of_memory();
+ return;
+ }

- if (!user_mode(regs))
- goto no_context;
+ if (fault & VM_FAULT_SIGBUS) {
+ sig = SIGBUS;
+ si_code = BUS_ADRERR;
+ }
+ else {
+ sig = SIGSEGV;
+ }

tsk->thread.fault_address = address;
- force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *)address, tsk);
+ force_sig_fault(sig, si_code, (void __user *)address, tsk);
return;

no_context:
--
2.7.4
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