MIPS: Use set_current_blocked() and block_sigmask()

As described in e6fa16ab ("signal: sigprocmask() should do
retarget_shared_pending()") the modification of current->blocked is
incorrect as we need to check whether the signal we're about to block
is pending in the shared queue.

Also, use the new helper function introduced in commit 5e6292c0
("signal: add block_sigmask() for adding sigmask to current->blocked")
which centralises the code for updating current->blocked after
successfully delivering a signal and reduces the amount of duplicate
code across architectures. In the past some architectures got this
code wrong, so using this helper function should stop that from
happening again.

Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: David Daney <ddaney@caviumnetworks.com>
Cc: linux-mips@linux-mips.org
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Patchwork: https://patchwork.linux-mips.org/patch/3363/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/kernel/signal.c

@@ -257,11 +257,8 @@ asmlinkage int sys_sigsuspend(nabi_no_regargs struct pt_regs regs)
 		return -EFAULT;
 	sigdelsetmask(&newset, ~_BLOCKABLE);
 
-	spin_lock_irq(&current->sighand->siglock);
 	current->saved_sigmask = current->blocked;
-	current->blocked = newset;
-	recalc_sigpending();
-	spin_unlock_irq(&current->sighand->siglock);
+	set_current_blocked(&newset);
 
 	current->state = TASK_INTERRUPTIBLE;
 	schedule();
@@ -286,11 +283,8 @@ asmlinkage int sys_rt_sigsuspend(nabi_no_regargs struct pt_regs regs)
 		return -EFAULT;
 	sigdelsetmask(&newset, ~_BLOCKABLE);
 
-	spin_lock_irq(&current->sighand->siglock);
 	current->saved_sigmask = current->blocked;
-	current->blocked = newset;
-	recalc_sigpending();
-	spin_unlock_irq(&current->sighand->siglock);
+	set_current_blocked(&newset);
 
 	current->state = TASK_INTERRUPTIBLE;
 	schedule();
@@ -362,10 +356,7 @@ asmlinkage void sys_sigreturn(nabi_no_regargs struct pt_regs regs)
 		goto badframe;
 
 	sigdelsetmask(&blocked, ~_BLOCKABLE);
-	spin_lock_irq(&current->sighand->siglock);
-	current->blocked = blocked;
-	recalc_sigpending();
-	spin_unlock_irq(&current->sighand->siglock);
+	set_current_blocked(&blocked);
 
 	sig = restore_sigcontext(&regs, &frame->sf_sc);
 	if (sig < 0)
@@ -401,10 +392,7 @@ asmlinkage void sys_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
 		goto badframe;
 
 	sigdelsetmask(&set, ~_BLOCKABLE);
-	spin_lock_irq(&current->sighand->siglock);
-	current->blocked = set;
-	recalc_sigpending();
-	spin_unlock_irq(&current->sighand->siglock);
+	set_current_blocked(&set);
 
 	sig = restore_sigcontext(&regs, &frame->rs_uc.uc_mcontext);
 	if (sig < 0)
@@ -580,12 +568,7 @@ static int handle_signal(unsigned long sig, siginfo_t *info,
 	if (ret)
 		return ret;
 
-	spin_lock_irq(&current->sighand->siglock);
-	sigorsets(&current->blocked, &current->blocked, &ka->sa.sa_mask);
-	if (!(ka->sa.sa_flags & SA_NODEFER))
-		sigaddset(&current->blocked, sig);
-	recalc_sigpending();
-	spin_unlock_irq(&current->sighand->siglock);
+	block_sigmask(ka, sig);
 
 	return ret;
 }

arch/mips/kernel/signal32.c

@@ -290,11 +290,8 @@ asmlinkage int sys32_sigsuspend(nabi_no_regargs struct pt_regs regs)
 		return -EFAULT;
 	sigdelsetmask(&newset, ~_BLOCKABLE);
 
-	spin_lock_irq(&current->sighand->siglock);
 	current->saved_sigmask = current->blocked;
-	current->blocked = newset;
-	recalc_sigpending();
-	spin_unlock_irq(&current->sighand->siglock);
+	set_current_blocked(&newset);
 
 	current->state = TASK_INTERRUPTIBLE;
 	schedule();
@@ -318,11 +315,8 @@ asmlinkage int sys32_rt_sigsuspend(nabi_no_regargs struct pt_regs regs)
 		return -EFAULT;
 	sigdelsetmask(&newset, ~_BLOCKABLE);
 
-	spin_lock_irq(&current->sighand->siglock);
 	current->saved_sigmask = current->blocked;
-	current->blocked = newset;
-	recalc_sigpending();
-	spin_unlock_irq(&current->sighand->siglock);
+	set_current_blocked(&newset);
 
 	current->state = TASK_INTERRUPTIBLE;
 	schedule();
@@ -488,10 +482,7 @@ asmlinkage void sys32_sigreturn(nabi_no_regargs struct pt_regs regs)
 		goto badframe;
 
 	sigdelsetmask(&blocked, ~_BLOCKABLE);
-	spin_lock_irq(&current->sighand->siglock);
-	current->blocked = blocked;
-	recalc_sigpending();
-	spin_unlock_irq(&current->sighand->siglock);
+	set_current_blocked(&blocked);
 
 	sig = restore_sigcontext32(&regs, &frame->sf_sc);
 	if (sig < 0)
@@ -529,10 +520,7 @@ asmlinkage void sys32_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
 		goto badframe;
 
 	sigdelsetmask(&set, ~_BLOCKABLE);
-	spin_lock_irq(&current->sighand->siglock);
-	current->blocked = set;
-	recalc_sigpending();
-	spin_unlock_irq(&current->sighand->siglock);
+	set_current_blocked(&set);
 
 	sig = restore_sigcontext32(&regs, &frame->rs_uc.uc_mcontext);
 	if (sig < 0)

arch/mips/kernel/signal_n32.c

@@ -93,11 +93,8 @@ asmlinkage int sysn32_rt_sigsuspend(nabi_no_regargs struct pt_regs regs)
 	sigset_from_compat(&newset, &uset);
 	sigdelsetmask(&newset, ~_BLOCKABLE);
 
-	spin_lock_irq(&current->sighand->siglock);
 	current->saved_sigmask = current->blocked;
-	current->blocked = newset;
-	recalc_sigpending();
-	spin_unlock_irq(&current->sighand->siglock);
+	set_current_blocked(&newset);
 
 	current->state = TASK_INTERRUPTIBLE;
 	schedule();
@@ -121,10 +118,7 @@ asmlinkage void sysn32_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
 		goto badframe;
 
 	sigdelsetmask(&set, ~_BLOCKABLE);
-	spin_lock_irq(&current->sighand->siglock);
-	current->blocked = set;
-	recalc_sigpending();
-	spin_unlock_irq(&current->sighand->siglock);
+	set_current_blocked(&set);
 
 	sig = restore_sigcontext(&regs, &frame->rs_uc.uc_mcontext);
 	if (sig < 0)