Merge 4.9.24 into android-4.9

Changes in 4.9.24:
	cgroup, kthread: close race window where new kthreads can be migrated to non-root cgroups
	tcmu: Fix possible overwrite of t_data_sg's last iov[]
	tcmu: Fix wrongly calculating of the base_command_size
	tcmu: Skip Data-Out blocks before gathering Data-In buffer for BIDI case
	thp: fix MADV_DONTNEED vs. MADV_FREE race
	thp: fix MADV_DONTNEED vs clear soft dirty race
	zsmalloc: expand class bit
	orangefs: free superblock when mount fails
	drm/nouveau/mpeg: mthd returns true on success now
	drm/nouveau/mmu/nv4a: use nv04 mmu rather than the nv44 one
	drm/etnaviv: fix missing unlock on error in etnaviv_gpu_submit()
	CIFS: reconnect thread reschedule itself
	CIFS: store results of cifs_reopen_file to avoid infinite wait
	Input: xpad - add support for Razer Wildcat gamepad
	perf/x86: Avoid exposing wrong/stale data in intel_pmu_lbr_read_32()
	x86/efi: Don't try to reserve runtime regions
	x86/signals: Fix lower/upper bound reporting in compat siginfo
	x86, pmem: fix broken __copy_user_nocache cache-bypass assumptions
	x86/vdso: Ensure vdso32_enabled gets set to valid values only
	x86/vdso: Plug race between mapping and ELF header setup
	acpi, nfit, libnvdimm: fix interleave set cookie calculation (64-bit comparison)
	ACPI / scan: Set the visited flag for all enumerated devices
	parisc: fix bugs in pa_memcpy
	efi/libstub: Skip GOP with PIXEL_BLT_ONLY format
	efi/fb: Avoid reconfiguration of BAR that covers the framebuffer
	iscsi-target: Fix TMR reference leak during session shutdown
	iscsi-target: Drop work-around for legacy GlobalSAN initiator
	scsi: sr: Sanity check returned mode data
	scsi: sd: Consider max_xfer_blocks if opt_xfer_blocks is unusable
	scsi: qla2xxx: Add fix to read correct register value for ISP82xx.
	scsi: sd: Fix capacity calculation with 32-bit sector_t
	target: Avoid mappedlun symlink creation during lun shutdown
	xen, fbfront: fix connecting to backend
	new privimitive: iov_iter_revert()
	make skb_copy_datagram_msg() et.al. preserve ->msg_iter on error
	libnvdimm: fix blk free space accounting
	libnvdimm: fix reconfig_mutex, mmap_sem, and jbd2_handle lockdep splat
	can: ifi: use correct register to read rx status
	pwm: rockchip: State of PWM clock should synchronize with PWM enabled state
	cpufreq: Bring CPUs up even if cpufreq_online() failed
	irqchip/irq-imx-gpcv2: Fix spinlock initialization
	ftrace: Fix removing of second function probe
	char: lack of bool string made CONFIG_DEVPORT always on
	Revert "MIPS: Lantiq: Fix cascaded IRQ setup"
	kvm: fix page struct leak in handle_vmon
	zram: do not use copy_page with non-page aligned address
	ftrace: Fix function pid filter on instances
	crypto: algif_aead - Fix bogus request dereference in completion function
	crypto: ahash - Fix EINPROGRESS notification callback
	parisc: Fix get_user() for 64-bit value on 32-bit kernel
	ath9k: fix NULL pointer dereference
	dvb-usb-v2: avoid use-after-free
	ext4: fix inode checksum calculation problem if i_extra_size is small
	mm: memcontrol: use special workqueue for creating per-memcg caches
	drm/nouveau/disp/mcp7x: disable dptmds workaround
	nbd: use loff_t for blocksize and nbd_set_size args
	nbd: fix 64-bit division
	ASoC: Intel: select DW_DMAC_CORE since it's mandatory
	platform/x86: acer-wmi: setup accelerometer when machine has appropriate notify event
	x86/xen: Fix APIC id mismatch warning on Intel
	ACPI / EC: Use busy polling mode when GPE is not enabled
	rtc: tegra: Implement clock handling
	mm: Tighten x86 /dev/mem with zeroing reads
	dvb-usb: don't use stack for firmware load
	dvb-usb-firmware: don't do DMA on stack
	cxusb: Use a dma capable buffer also for reading
	virtio-console: avoid DMA from stack
	net: ipv6: check route protocol when deleting routes
	sctp: deny peeloff operation on asocs with threads sleeping on it
	Linux 4.9.24

Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

lib/iov_iter.c

@@ -734,6 +734,68 @@ void iov_iter_advance(struct iov_iter *i, size_t size)
 }
 EXPORT_SYMBOL(iov_iter_advance);
 
+void iov_iter_revert(struct iov_iter *i, size_t unroll)
+{
+	if (!unroll)
+		return;
+	i->count += unroll;
+	if (unlikely(i->type & ITER_PIPE)) {
+		struct pipe_inode_info *pipe = i->pipe;
+		int idx = i->idx;
+		size_t off = i->iov_offset;
+		while (1) {
+			size_t n = off - pipe->bufs[idx].offset;
+			if (unroll < n) {
+				off -= (n - unroll);
+				break;
+			}
+			unroll -= n;
+			if (!unroll && idx == i->start_idx) {
+				off = 0;
+				break;
+			}
+			if (!idx--)
+				idx = pipe->buffers - 1;
+			off = pipe->bufs[idx].offset + pipe->bufs[idx].len;
+		}
+		i->iov_offset = off;
+		i->idx = idx;
+		pipe_truncate(i);
+		return;
+	}
+	if (unroll <= i->iov_offset) {
+		i->iov_offset -= unroll;
+		return;
+	}
+	unroll -= i->iov_offset;
+	if (i->type & ITER_BVEC) {
+		const struct bio_vec *bvec = i->bvec;
+		while (1) {
+			size_t n = (--bvec)->bv_len;
+			i->nr_segs++;
+			if (unroll <= n) {
+				i->bvec = bvec;
+				i->iov_offset = n - unroll;
+				return;
+			}
+			unroll -= n;
+		}
+	} else { /* same logics for iovec and kvec */
+		const struct iovec *iov = i->iov;
+		while (1) {
+			size_t n = (--iov)->iov_len;
+			i->nr_segs++;
+			if (unroll <= n) {
+				i->iov = iov;
+				i->iov_offset = n - unroll;
+				return;
+			}
+			unroll -= n;
+		}
+	}
+}
+EXPORT_SYMBOL(iov_iter_revert);
+
 /*
  * Return the count of just the current iov_iter segment.
  */
@@ -787,6 +849,7 @@ void iov_iter_pipe(struct iov_iter *i, int direction,
 	i->idx = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1);
 	i->iov_offset = 0;
 	i->count = count;
+	i->start_idx = i->idx;
 }
 EXPORT_SYMBOL(iov_iter_pipe);