Merge branch 'linus' into perf/core

Conflicts:
	arch/sparc/kernel/perf_event.c

Merge reason: Resolve the conflict.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/powerpc/kernel/signal.c

@@ -138,6 +138,7 @@ static int do_signal_pending(sigset_t *oldset, struct pt_regs *regs)
 			ti->local_flags &= ~_TLF_RESTORE_SIGMASK;
 			sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 		}
+		regs->trap = 0;
 		return 0;               /* no signals delivered */
 	}
 
@@ -164,6 +165,7 @@ static int do_signal_pending(sigset_t *oldset, struct pt_regs *regs)
 		ret = handle_rt_signal64(signr, &ka, &info, oldset, regs);
 	}
 
+	regs->trap = 0;
 	if (ret) {
 		spin_lock_irq(&current->sighand->siglock);
 		sigorsets(&current->blocked, &current->blocked,

arch/powerpc/kernel/signal_32.c

@@ -511,6 +511,7 @@ static long restore_user_regs(struct pt_regs *regs,
 	if (!sig)
 		save_r2 = (unsigned int)regs->gpr[2];
 	err = restore_general_regs(regs, sr);
+	regs->trap = 0;
 	err |= __get_user(msr, &sr->mc_gregs[PT_MSR]);
 	if (!sig)
 		regs->gpr[2] = (unsigned long) save_r2;
@@ -884,7 +885,6 @@ int handle_rt_signal32(unsigned long sig, struct k_sigaction *ka,
 	regs->nip = (unsigned long) ka->sa.sa_handler;
 	/* enter the signal handler in big-endian mode */
 	regs->msr &= ~MSR_LE;
-	regs->trap = 0;
 	return 1;
 
 badframe:
@@ -1228,7 +1228,6 @@ int handle_signal32(unsigned long sig, struct k_sigaction *ka,
 	regs->nip = (unsigned long) ka->sa.sa_handler;
 	/* enter the signal handler in big-endian mode */
 	regs->msr &= ~MSR_LE;
-	regs->trap = 0;
 
 	return 1;
 

arch/powerpc/kernel/signal_64.c

@@ -178,7 +178,7 @@ static long restore_sigcontext(struct pt_regs *regs, sigset_t *set, int sig,
 	err |= __get_user(regs->xer, &sc->gp_regs[PT_XER]);
 	err |= __get_user(regs->ccr, &sc->gp_regs[PT_CCR]);
 	/* skip SOFTE */
-	err |= __get_user(regs->trap, &sc->gp_regs[PT_TRAP]);
+	regs->trap = 0;
 	err |= __get_user(regs->dar, &sc->gp_regs[PT_DAR]);
 	err |= __get_user(regs->dsisr, &sc->gp_regs[PT_DSISR]);
 	err |= __get_user(regs->result, &sc->gp_regs[PT_RESULT]);

arch/sparc/kernel/perf_event.c

@@ -1076,13 +1076,24 @@ static int sparc_pmu_event_init(struct perf_event *event)
 		break;
 
 	case PERF_TYPE_RAW:
-		return -EOPNOTSUPP;
+		pmap = NULL;
+		break;
 
 	default:
 		return -ENOENT;
 
 	}
 
+	if (pmap) {
+		hwc->event_base = perf_event_encode(pmap);
+	} else {
+		/*
+		 * User gives us "(encoding << 16) | pic_mask" for
+		 * PERF_TYPE_RAW events.
+		 */
+		hwc->event_base = attr->config;
+	}
+
 	/* We save the enable bits in the config_base.  */
 	hwc->config_base = sparc_pmu->irq_bit;
 	if (!attr->exclude_user)
@@ -1092,8 +1103,6 @@ static int sparc_pmu_event_init(struct perf_event *event)
 	if (!attr->exclude_hv)
 		hwc->config_base |= sparc_pmu->hv_bit;
 
-	hwc->event_base = perf_event_encode(pmap);
-
 	n = 0;
 	if (event->group_leader != event) {
 		n = collect_events(event->group_leader,

arch/sparc/kernel/signal32.c

@@ -453,8 +453,66 @@ static int save_fpu_state32(struct pt_regs *regs, __siginfo_fpu_t __user *fpu)
 	return err;
 }
 
-static void setup_frame32(struct k_sigaction *ka, struct pt_regs *regs,
-			  int signo, sigset_t *oldset)
+/* The I-cache flush instruction only works in the primary ASI, which
+ * right now is the nucleus, aka. kernel space.
+ *
+ * Therefore we have to kick the instructions out using the kernel
+ * side linear mapping of the physical address backing the user
+ * instructions.
+ */
+static void flush_signal_insns(unsigned long address)
+{
+	unsigned long pstate, paddr;
+	pte_t *ptep, pte;
+	pgd_t *pgdp;
+	pud_t *pudp;
+	pmd_t *pmdp;
+
+	/* Commit all stores of the instructions we are about to flush.  */
+	wmb();
+
+	/* Disable cross-call reception.  In this way even a very wide
+	 * munmap() on another cpu can't tear down the page table
+	 * hierarchy from underneath us, since that can't complete
+	 * until the IPI tlb flush returns.
+	 */
+
+	__asm__ __volatile__("rdpr %%pstate, %0" : "=r" (pstate));
+	__asm__ __volatile__("wrpr %0, %1, %%pstate"
+				: : "r" (pstate), "i" (PSTATE_IE));
+
+	pgdp = pgd_offset(current->mm, address);
+	if (pgd_none(*pgdp))
+		goto out_irqs_on;
+	pudp = pud_offset(pgdp, address);
+	if (pud_none(*pudp))
+		goto out_irqs_on;
+	pmdp = pmd_offset(pudp, address);
+	if (pmd_none(*pmdp))
+		goto out_irqs_on;
+
+	ptep = pte_offset_map(pmdp, address);
+	pte = *ptep;
+	if (!pte_present(pte))
+		goto out_unmap;
+
+	paddr = (unsigned long) page_address(pte_page(pte));
+
+	__asm__ __volatile__("flush	%0 + %1"
+			     : /* no outputs */
+			     : "r" (paddr),
+			       "r" (address & (PAGE_SIZE - 1))
+			     : "memory");
+
+out_unmap:
+	pte_unmap(ptep);
+out_irqs_on:
+	__asm__ __volatile__("wrpr %0, 0x0, %%pstate" : : "r" (pstate));
+
+}
+
+static int setup_frame32(struct k_sigaction *ka, struct pt_regs *regs,
+			 int signo, sigset_t *oldset)
 {
 	struct signal_frame32 __user *sf;
 	int sigframe_size;
@@ -547,13 +605,7 @@ static void setup_frame32(struct k_sigaction *ka, struct pt_regs *regs,
 	if (ka->ka_restorer) {
 		regs->u_regs[UREG_I7] = (unsigned long)ka->ka_restorer;
 	} else {
-		/* Flush instruction space. */
 		unsigned long address = ((unsigned long)&(sf->insns[0]));
-		pgd_t *pgdp = pgd_offset(current->mm, address);
-		pud_t *pudp = pud_offset(pgdp, address);
-		pmd_t *pmdp = pmd_offset(pudp, address);
-		pte_t *ptep;
-		pte_t pte;
 
 		regs->u_regs[UREG_I7] = (unsigned long) (&(sf->insns[0]) - 2);
 	
@@ -562,34 +614,22 @@ static void setup_frame32(struct k_sigaction *ka, struct pt_regs *regs,
 		if (err)
 			goto sigsegv;
 
-		preempt_disable();
-		ptep = pte_offset_map(pmdp, address);
-		pte = *ptep;
-		if (pte_present(pte)) {
-			unsigned long page = (unsigned long)
-				page_address(pte_page(pte));
-
-			wmb();
-			__asm__ __volatile__("flush	%0 + %1"
-					     : /* no outputs */
-					     : "r" (page),
-					       "r" (address & (PAGE_SIZE - 1))
-					     : "memory");
-		}
-		pte_unmap(ptep);
-		preempt_enable();
+		flush_signal_insns(address);
 	}
-	return;
+	return 0;
 
 sigill:
 	do_exit(SIGILL);
+	return -EINVAL;
+
 sigsegv:
 	force_sigsegv(signo, current);
+	return -EFAULT;
 }
 
-static void setup_rt_frame32(struct k_sigaction *ka, struct pt_regs *regs,
-			     unsigned long signr, sigset_t *oldset,
-			     siginfo_t *info)
+static int setup_rt_frame32(struct k_sigaction *ka, struct pt_regs *regs,
+			    unsigned long signr, sigset_t *oldset,
+			    siginfo_t *info)
 {
 	struct rt_signal_frame32 __user *sf;
 	int sigframe_size;
@@ -687,12 +727,7 @@ static void setup_rt_frame32(struct k_sigaction *ka, struct pt_regs *regs,
 	if (ka->ka_restorer)
 		regs->u_regs[UREG_I7] = (unsigned long)ka->ka_restorer;
 	else {
-		/* Flush instruction space. */
 		unsigned long address = ((unsigned long)&(sf->insns[0]));
-		pgd_t *pgdp = pgd_offset(current->mm, address);
-		pud_t *pudp = pud_offset(pgdp, address);
-		pmd_t *pmdp = pmd_offset(pudp, address);
-		pte_t *ptep;
 
 		regs->u_regs[UREG_I7] = (unsigned long) (&(sf->insns[0]) - 2);
 	
@@ -704,38 +739,32 @@ static void setup_rt_frame32(struct k_sigaction *ka, struct pt_regs *regs,
 		if (err)
 			goto sigsegv;
 
-		preempt_disable();
-		ptep = pte_offset_map(pmdp, address);
-		if (pte_present(*ptep)) {
-			unsigned long page = (unsigned long)
-				page_address(pte_page(*ptep));
-
-			wmb();
-			__asm__ __volatile__("flush	%0 + %1"
-					     : /* no outputs */
-					     : "r" (page),
-					       "r" (address & (PAGE_SIZE - 1))
-					     : "memory");
-		}
-		pte_unmap(ptep);
-		preempt_enable();
+		flush_signal_insns(address);
 	}
-	return;
+	return 0;
 
 sigill:
 	do_exit(SIGILL);
+	return -EINVAL;
+
 sigsegv:
 	force_sigsegv(signr, current);
+	return -EFAULT;
 }
 
-static inline void handle_signal32(unsigned long signr, struct k_sigaction *ka,
-				   siginfo_t *info,
-				   sigset_t *oldset, struct pt_regs *regs)
+static inline int handle_signal32(unsigned long signr, struct k_sigaction *ka,
+				  siginfo_t *info,
+				  sigset_t *oldset, struct pt_regs *regs)
 {
+	int err;
+
 	if (ka->sa.sa_flags & SA_SIGINFO)
-		setup_rt_frame32(ka, regs, signr, oldset, info);
+		err = setup_rt_frame32(ka, regs, signr, oldset, info);
 	else
-		setup_frame32(ka, regs, signr, oldset);
+		err = setup_frame32(ka, regs, signr, oldset);
+
+	if (err)
+		return err;
 
 	spin_lock_irq(&current->sighand->siglock);
 	sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
@@ -743,6 +772,10 @@ static inline void handle_signal32(unsigned long signr, struct k_sigaction *ka,
 		sigaddset(&current->blocked,signr);
 	recalc_sigpending();
 	spin_unlock_irq(&current->sighand->siglock);
+
+	tracehook_signal_handler(signr, info, ka, regs, 0);
+
+	return 0;
 }
 
 static inline void syscall_restart32(unsigned long orig_i0, struct pt_regs *regs,
@@ -789,16 +822,14 @@ void do_signal32(sigset_t *oldset, struct pt_regs * regs,
 	if (signr > 0) {
 		if (restart_syscall)
 			syscall_restart32(orig_i0, regs, &ka.sa);
-		handle_signal32(signr, &ka, &info, oldset, regs);
-
-		/* A signal was successfully delivered; the saved
-		 * sigmask will have been stored in the signal frame,
-		 * and will be restored by sigreturn, so we can simply
-		 * clear the TS_RESTORE_SIGMASK flag.
-		 */
-		current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
-
-		tracehook_signal_handler(signr, &info, &ka, regs, 0);
+		if (handle_signal32(signr, &ka, &info, oldset, regs) == 0) {
+			/* A signal was successfully delivered; the saved
+			 * sigmask will have been stored in the signal frame,
+			 * and will be restored by sigreturn, so we can simply
+			 * clear the TS_RESTORE_SIGMASK flag.
+			 */
+			current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
+		}
 		return;
 	}
 	if (restart_syscall &&
@@ -809,12 +840,14 @@ void do_signal32(sigset_t *oldset, struct pt_regs * regs,
 		regs->u_regs[UREG_I0] = orig_i0;
 		regs->tpc -= 4;
 		regs->tnpc -= 4;
+		pt_regs_clear_syscall(regs);
 	}
 	if (restart_syscall &&
 	    regs->u_regs[UREG_I0] == ERESTART_RESTARTBLOCK) {
 		regs->u_regs[UREG_G1] = __NR_restart_syscall;
 		regs->tpc -= 4;
 		regs->tnpc -= 4;
+		pt_regs_clear_syscall(regs);
 	}
 
 	/* If there's no signal to deliver, we just put the saved sigmask

arch/sparc/kernel/signal_32.c

@@ -315,8 +315,8 @@ save_fpu_state(struct pt_regs *regs, __siginfo_fpu_t __user *fpu)
 	return err;
 }
 
-static void setup_frame(struct k_sigaction *ka, struct pt_regs *regs,
-			int signo, sigset_t *oldset)
+static int setup_frame(struct k_sigaction *ka, struct pt_regs *regs,
+		       int signo, sigset_t *oldset)
 {
 	struct signal_frame __user *sf;
 	int sigframe_size, err;
@@ -384,16 +384,19 @@ static void setup_frame(struct k_sigaction *ka, struct pt_regs *regs,
 		/* Flush instruction space. */
 		flush_sig_insns(current->mm, (unsigned long) &(sf->insns[0]));
 	}
-	return;
+	return 0;
 
 sigill_and_return:
 	do_exit(SIGILL);
+	return -EINVAL;
+
 sigsegv:
 	force_sigsegv(signo, current);
+	return -EFAULT;
 }
 
-static void setup_rt_frame(struct k_sigaction *ka, struct pt_regs *regs,
-			   int signo, sigset_t *oldset, siginfo_t *info)
+static int setup_rt_frame(struct k_sigaction *ka, struct pt_regs *regs,
+			  int signo, sigset_t *oldset, siginfo_t *info)
 {
 	struct rt_signal_frame __user *sf;
 	int sigframe_size;
@@ -466,22 +469,30 @@ static void setup_rt_frame(struct k_sigaction *ka, struct pt_regs *regs,
 		/* Flush instruction space. */
 		flush_sig_insns(current->mm, (unsigned long) &(sf->insns[0]));
 	}
-	return;
+	return 0;
 
 sigill:
 	do_exit(SIGILL);
+	return -EINVAL;
+
 sigsegv:
 	force_sigsegv(signo, current);
+	return -EFAULT;
 }
 
-static inline void
+static inline int
 handle_signal(unsigned long signr, struct k_sigaction *ka,
 	      siginfo_t *info, sigset_t *oldset, struct pt_regs *regs)
 {
+	int err;
+
 	if (ka->sa.sa_flags & SA_SIGINFO)
-		setup_rt_frame(ka, regs, signr, oldset, info);
+		err = setup_rt_frame(ka, regs, signr, oldset, info);
 	else
-		setup_frame(ka, regs, signr, oldset);
+		err = setup_frame(ka, regs, signr, oldset);
+
+	if (err)
+		return err;
 
 	spin_lock_irq(&current->sighand->siglock);
 	sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
@@ -489,6 +500,10 @@ handle_signal(unsigned long signr, struct k_sigaction *ka,
 		sigaddset(&current->blocked, signr);
 	recalc_sigpending();
 	spin_unlock_irq(&current->sighand->siglock);
+
+	tracehook_signal_handler(signr, info, ka, regs, 0);
+
+	return 0;
 }
 
 static inline void syscall_restart(unsigned long orig_i0, struct pt_regs *regs,
@@ -546,17 +561,15 @@ static void do_signal(struct pt_regs *regs, unsigned long orig_i0)
 	if (signr > 0) {
 		if (restart_syscall)
 			syscall_restart(orig_i0, regs, &ka.sa);
-		handle_signal(signr, &ka, &info, oldset, regs);
-
-		/* a signal was successfully delivered; the saved
-		 * sigmask will have been stored in the signal frame,
-		 * and will be restored by sigreturn, so we can simply
-		 * clear the TIF_RESTORE_SIGMASK flag.
-		 */
-		if (test_thread_flag(TIF_RESTORE_SIGMASK))
-			clear_thread_flag(TIF_RESTORE_SIGMASK);
-
-		tracehook_signal_handler(signr, &info, &ka, regs, 0);
+		if (handle_signal(signr, &ka, &info, oldset, regs) == 0) {
+			/* a signal was successfully delivered; the saved
+			 * sigmask will have been stored in the signal frame,
+			 * and will be restored by sigreturn, so we can simply
+			 * clear the TIF_RESTORE_SIGMASK flag.
+			 */
+			if (test_thread_flag(TIF_RESTORE_SIGMASK))
+				clear_thread_flag(TIF_RESTORE_SIGMASK);
+		}
 		return;
 	}
 	if (restart_syscall &&
@@ -567,12 +580,14 @@ static void do_signal(struct pt_regs *regs, unsigned long orig_i0)
 		regs->u_regs[UREG_I0] = orig_i0;
 		regs->pc -= 4;
 		regs->npc -= 4;
+		pt_regs_clear_syscall(regs);
 	}
 	if (restart_syscall &&
 	    regs->u_regs[UREG_I0] == ERESTART_RESTARTBLOCK) {
 		regs->u_regs[UREG_G1] = __NR_restart_syscall;
 		regs->pc -= 4;
 		regs->npc -= 4;
+		pt_regs_clear_syscall(regs);
 	}
 
 	/* if there's no signal to deliver, we just put the saved sigmask

arch/sparc/kernel/signal_64.c

@@ -409,7 +409,7 @@ static inline void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *
 	return (void __user *) sp;
 }
 
-static inline void
+static inline int
 setup_rt_frame(struct k_sigaction *ka, struct pt_regs *regs,
 	       int signo, sigset_t *oldset, siginfo_t *info)
 {
@@ -483,26 +483,37 @@ setup_rt_frame(struct k_sigaction *ka, struct pt_regs *regs,
 	}
 	/* 4. return to kernel instructions */
 	regs->u_regs[UREG_I7] = (unsigned long)ka->ka_restorer;
-	return;
+	return 0;
 
 sigill:
 	do_exit(SIGILL);
+	return -EINVAL;
+
 sigsegv:
 	force_sigsegv(signo, current);
+	return -EFAULT;
 }
 
-static inline void handle_signal(unsigned long signr, struct k_sigaction *ka,
-				 siginfo_t *info,
-				 sigset_t *oldset, struct pt_regs *regs)
+static inline int handle_signal(unsigned long signr, struct k_sigaction *ka,
+				siginfo_t *info,
+				sigset_t *oldset, struct pt_regs *regs)
 {
-	setup_rt_frame(ka, regs, signr, oldset,
-		       (ka->sa.sa_flags & SA_SIGINFO) ? info : NULL);
+	int err;
+
+	err = setup_rt_frame(ka, regs, signr, oldset,
+			     (ka->sa.sa_flags & SA_SIGINFO) ? info : NULL);
+	if (err)
+		return err;
 	spin_lock_irq(&current->sighand->siglock);
 	sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
 	if (!(ka->sa.sa_flags & SA_NOMASK))
 		sigaddset(&current->blocked,signr);
 	recalc_sigpending();
 	spin_unlock_irq(&current->sighand->siglock);
+
+	tracehook_signal_handler(signr, info, ka, regs, 0);
+
+	return 0;
 }
 
 static inline void syscall_restart(unsigned long orig_i0, struct pt_regs *regs,
@@ -571,16 +582,14 @@ static void do_signal(struct pt_regs *regs, unsigned long orig_i0)
 	if (signr > 0) {
 		if (restart_syscall)
 			syscall_restart(orig_i0, regs, &ka.sa);
-		handle_signal(signr, &ka, &info, oldset, regs);
-
-		/* A signal was successfully delivered; the saved
-		 * sigmask will have been stored in the signal frame,
-		 * and will be restored by sigreturn, so we can simply
-		 * clear the TS_RESTORE_SIGMASK flag.
-		 */
-		current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
-
-		tracehook_signal_handler(signr, &info, &ka, regs, 0);
+		if (handle_signal(signr, &ka, &info, oldset, regs) == 0) {
+			/* A signal was successfully delivered; the saved
+			 * sigmask will have been stored in the signal frame,
+			 * and will be restored by sigreturn, so we can simply
+			 * clear the TS_RESTORE_SIGMASK flag.
+			 */
+			current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
+		}
 		return;
 	}
 	if (restart_syscall &&
@@ -591,12 +600,14 @@ static void do_signal(struct pt_regs *regs, unsigned long orig_i0)
 		regs->u_regs[UREG_I0] = orig_i0;
 		regs->tpc -= 4;
 		regs->tnpc -= 4;
+		pt_regs_clear_syscall(regs);
 	}
 	if (restart_syscall &&
 	    regs->u_regs[UREG_I0] == ERESTART_RESTARTBLOCK) {
 		regs->u_regs[UREG_G1] = __NR_restart_syscall;
 		regs->tpc -= 4;
 		regs->tnpc -= 4;
+		pt_regs_clear_syscall(regs);
 	}
 
 	/* If there's no signal to deliver, we just put the saved sigmask

block/blk-map.c

@@ -307,7 +307,7 @@ int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
 		return PTR_ERR(bio);
 
 	if (rq_data_dir(rq) == WRITE)
-		bio->bi_rw |= (1 << REQ_WRITE);
+		bio->bi_rw |= REQ_WRITE;
 
 	if (do_copy)
 		rq->cmd_flags |= REQ_COPY_USER;

block/cfq-iosched.c

@@ -1019,10 +1019,20 @@ cfq_find_alloc_cfqg(struct cfq_data *cfqd, struct cgroup *cgroup, int create)
 	 */
 	atomic_set(&cfqg->ref, 1);
 
-	/* Add group onto cgroup list */
-	sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor);
-	cfq_blkiocg_add_blkio_group(blkcg, &cfqg->blkg, (void *)cfqd,
+	/*
+	 * Add group onto cgroup list. It might happen that bdi->dev is
+	 * not initiliazed yet. Initialize this new group without major
+	 * and minor info and this info will be filled in once a new thread
+	 * comes for IO. See code above.
+	 */
+	if (bdi->dev) {
+		sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor);
+		cfq_blkiocg_add_blkio_group(blkcg, &cfqg->blkg, (void *)cfqd,
 					MKDEV(major, minor));
+	} else
+		cfq_blkiocg_add_blkio_group(blkcg, &cfqg->blkg, (void *)cfqd,
+					0);
+
 	cfqg->weight = blkcg_get_weight(blkcg, cfqg->blkg.dev);
 
 	/* Add group on cfqd list */

drivers/block/cciss.c

@@ -4792,7 +4792,7 @@ static int __devinit cciss_init_one(struct pci_dev *pdev,
 clean4:
 	kfree(h->cmd_pool_bits);
 	/* Free up sg elements */
-	for (k = 0; k < h->nr_cmds; k++)
+	for (k-- ; k >= 0; k--)
 		kfree(h->scatter_list[k]);
 	kfree(h->scatter_list);
 	cciss_free_sg_chain_blocks(h->cmd_sg_list, h->nr_cmds);

drivers/char/mem.c

@@ -788,10 +788,11 @@ static const struct file_operations zero_fops = {
 /*
  * capabilities for /dev/zero
  * - permits private mappings, "copies" are taken of the source of zeros
+ * - no writeback happens
  */
 static struct backing_dev_info zero_bdi = {
 	.name		= "char/mem",
-	.capabilities	= BDI_CAP_MAP_COPY,
+	.capabilities	= BDI_CAP_MAP_COPY | BDI_CAP_NO_ACCT_AND_WRITEBACK,
 };
 
 static const struct file_operations full_fops = {

drivers/i2c/busses/i2c-omap.c

@@ -680,6 +680,8 @@ omap_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 
 	if (r == 0)
 		r = num;
+
+	omap_i2c_wait_for_bb(dev);
 out:
 	omap_i2c_idle(dev);
 	return r;

fs/char_dev.c

@@ -40,7 +40,9 @@ struct backing_dev_info directly_mappable_cdev_bdi = {
 #endif
 		/* permit direct mmap, for read, write or exec */
 		BDI_CAP_MAP_DIRECT |
-		BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP | BDI_CAP_EXEC_MAP),
+		BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP | BDI_CAP_EXEC_MAP |
+		/* no writeback happens */
+		BDI_CAP_NO_ACCT_AND_WRITEBACK),
 };
 
 static struct kobj_map *cdev_map;

fs/fs-writeback.c

@@ -52,8 +52,6 @@ struct wb_writeback_work {
 #define CREATE_TRACE_POINTS
 #include <trace/events/writeback.h>
 
-#define inode_to_bdi(inode)	((inode)->i_mapping->backing_dev_info)
-
 /*
  * We don't actually have pdflush, but this one is exported though /proc...
  */
@@ -71,6 +69,27 @@ int writeback_in_progress(struct backing_dev_info *bdi)
 	return test_bit(BDI_writeback_running, &bdi->state);
 }
 
+static inline struct backing_dev_info *inode_to_bdi(struct inode *inode)
+{
+	struct super_block *sb = inode->i_sb;
+	struct backing_dev_info *bdi = inode->i_mapping->backing_dev_info;
+
+	/*
+	 * For inodes on standard filesystems, we use superblock's bdi. For
+	 * inodes on virtual filesystems, we want to use inode mapping's bdi
+	 * because they can possibly point to something useful (think about
+	 * block_dev filesystem).
+	 */
+	if (sb->s_bdi && sb->s_bdi != &noop_backing_dev_info) {
+		/* Some device inodes could play dirty tricks. Catch them... */
+		WARN(bdi != sb->s_bdi && bdi_cap_writeback_dirty(bdi),
+			"Dirtiable inode bdi %s != sb bdi %s\n",
+			bdi->name, sb->s_bdi->name);
+		return sb->s_bdi;
+	}
+	return bdi;
+}
+
 static void bdi_queue_work(struct backing_dev_info *bdi,
 		struct wb_writeback_work *work)
 {

mm/backing-dev.c

@@ -30,6 +30,7 @@ EXPORT_SYMBOL_GPL(default_backing_dev_info);
 
 struct backing_dev_info noop_backing_dev_info = {
 	.name		= "noop",
+	.capabilities	= BDI_CAP_NO_ACCT_AND_WRITEBACK,
 };
 EXPORT_SYMBOL_GPL(noop_backing_dev_info);
 
@@ -243,6 +244,7 @@ static int __init default_bdi_init(void)
 	err = bdi_init(&default_backing_dev_info);
 	if (!err)
 		bdi_register(&default_backing_dev_info, NULL, "default");
+	err = bdi_init(&noop_backing_dev_info);
 
 	return err;
 }