Merge branch 'akpm/master'

6 files changed, 51 insertions, 10 deletions

diff --git a/Documentation/ABI/testing/sysfs-class-bdi b/Documentation/ABI/testing/sysfs-class-bdi
index d773d5697cf5..3187a18af6da 100644
--- a/Documentation/ABI/testing/sysfs-class-bdi
+++ b/Documentation/ABI/testing/sysfs-class-bdi
@@ -53,3 +53,11 @@ stable_pages_required (read-only)
 
 	If set, the backing device requires that all pages comprising a write
 	request must not be changed until writeout is complete.
+
+strictlimit (read-write)
+
+	Forces per-BDI checks for the share of given device in the write-back
+	cache even before the global background dirty limit is reached. This
+	is useful in situations where the global limit is much higher than
+	affordable for given relatively slow (or untrusted) device. Turning
+	strictlimit on has no visible effect if max_ratio is equal to 100%.
diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index 0d1c680eb9bd..42fc139bbed4 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -153,7 +153,6 @@ EXPORT_SYMBOL(arm_dma_zone_size);
  * allocations.  This must be the smallest DMA mask in the system,
  * so a successful GFP_DMA allocation will always satisfy this.
  */
-phys_addr_t arm_dma_limit;
 unsigned long arm_dma_pfn_limit;
 
 static void __init arm_adjust_dma_zone(unsigned long *size, unsigned long *hole,
@@ -172,6 +171,8 @@ static void __init arm_adjust_dma_zone(unsigned long *size, unsigned long *hole,
 void __init setup_dma_zone(const struct machine_desc *mdesc)
 {
 #ifdef CONFIG_ZONE_DMA
+	phys_addr_t arm_dma_limit;
+
 	if (mdesc->dma_zone_size) {
 		arm_dma_zone_size = mdesc->dma_zone_size;
 		arm_dma_limit = PHYS_OFFSET + arm_dma_zone_size - 1;
@@ -327,7 +328,8 @@ void __init arm_memblock_init(struct meminfo *mi,
 	 * reserve memory for DMA contigouos allocations,
 	 * must come from DMA area inside low memory
 	 */
-	dma_contiguous_reserve(min(arm_dma_limit, arm_lowmem_limit));
+	dma_contiguous_reserve(min((phys_addr_t)arm_dma_pfn_limit << PAGE_SHIFT,
+				   arm_lowmem_limit));
 
 	arm_memblock_steal_permitted = false;
 	memblock_dump_all();
diff --git a/arch/arm/mm/mm.h b/arch/arm/mm/mm.h
index 7ea641b7aa7d..64a40d63cad5 100644
--- a/arch/arm/mm/mm.h
+++ b/arch/arm/mm/mm.h
@@ -81,10 +81,8 @@ extern __init void add_static_vm_early(struct static_vm *svm);
 #endif
 
 #ifdef CONFIG_ZONE_DMA
-extern phys_addr_t arm_dma_limit;
 extern unsigned long arm_dma_pfn_limit;
 #else
-#define arm_dma_limit ((phys_addr_t)~0)
 #define arm_dma_pfn_limit (~0ul >> PAGE_SHIFT)
 #endif
 
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index a7c3691456dd..99bc9c513b70 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -644,12 +644,11 @@ static int spi_map_msg(struct spi_master *master, struct spi_message *msg)
 	struct device *tx_dev, *rx_dev;
 	struct spi_transfer *xfer;
 	void *tmp;
-	unsigned int max_tx, max_rx;
 	int ret;
 
 	if (master->flags & (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX)) {
-		max_tx = 0;
-		max_rx = 0;
+		unsigned max_tx = 0;
+		unsigned max_rx = 0;
 
 		list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 			if ((master->flags & SPI_MASTER_MUST_TX) &&
diff --git a/drivers/w1/w1_int.c b/drivers/w1/w1_int.c
index 9b084db739c7..3aaa15f6b7e9 100644
--- a/drivers/w1/w1_int.c
+++ b/drivers/w1/w1_int.c
@@ -92,9 +92,8 @@ static struct w1_master * w1_alloc_dev(u32 id, int slave_count, int slave_ttl,
 	err = device_register(&dev->dev);
 	if (err) {
 		printk(KERN_ERR "Failed to register master device. err=%d\n", err);
-		memset(dev, 0, sizeof(struct w1_master));
-		kfree(dev);
-		dev = NULL;
+		put_device(&dev->dev);
+		return NULL;
 	}
 
 	return dev;
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index ce682f7a4f29..4ee1d64b52a2 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -234,11 +234,46 @@ static ssize_t stable_pages_required_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(stable_pages_required);
 
+static ssize_t strictlimit_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct backing_dev_info *bdi = dev_get_drvdata(dev);
+	unsigned int val;
+	ssize_t ret;
+
+	ret = kstrtouint(buf, 10, &val);
+	if (ret < 0)
+		return ret;
+
+	switch (val) {
+	case 0:
+		bdi->capabilities &= ~BDI_CAP_STRICTLIMIT;
+		break;
+	case 1:
+		bdi->capabilities |= BDI_CAP_STRICTLIMIT;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return count;
+}
+static ssize_t strictlimit_show(struct device *dev,
+		struct device_attribute *attr, char *page)
+{
+	struct backing_dev_info *bdi = dev_get_drvdata(dev);
+
+	return snprintf(page, PAGE_SIZE-1, "%d\n",
+			!!(bdi->capabilities & BDI_CAP_STRICTLIMIT));
+}
+static DEVICE_ATTR_RW(strictlimit);
+
 static struct attribute *bdi_dev_attrs[] = {
 	&dev_attr_read_ahead_kb.attr,
 	&dev_attr_min_ratio.attr,
 	&dev_attr_max_ratio.attr,
 	&dev_attr_stable_pages_required.attr,
+	&dev_attr_strictlimit.attr,
 	NULL,
 };
 ATTRIBUTE_GROUPS(bdi_dev);