Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block

* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  scatterlist: add more safeguards
  Revert "ll_rw_blk: temporarily enable max_segments tweaking"
  mmc: Add missing sg_init_table() call
  block: Fix memory leak in alloc_disk_node()
  alpha: fix sg_page breakage
  blktrace: Make sure BLKTRACETEARDOWN does the full cleanup.

6 files changed, 44 insertions, 43 deletions

diff --git a/arch/alpha/kernel/pci-noop.c b/arch/alpha/kernel/pci-noop.c
index 174b729c504b..468b76ce66a1 100644
--- a/arch/alpha/kernel/pci-noop.c
+++ b/arch/alpha/kernel/pci-noop.c
@@ -12,6 +12,7 @@
 #include <linux/errno.h>
 #include <linux/sched.h>
 #include <linux/dma-mapping.h>
+#include <linux/scatterlist.h>
 
 #include "proto.h"
 
@@ -172,18 +173,19 @@ dma_alloc_coherent(struct device *dev, size_t size,
 EXPORT_SYMBOL(dma_alloc_coherent);
 
 int
-dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
+dma_map_sg(struct device *dev, struct scatterlist *sgl, int nents,
            enum dma_data_direction direction)
 {
         int i;
+        struct scatterlist *sg;
 
-        for (i = 0; i < nents; i++ ) {
+        for_each_sg(sgl, sg, nents, i) {
                 void *va;
 
-                BUG_ON(!sg[i].page);
-                va = page_address(sg[i].page) + sg[i].offset;
-                sg_dma_address(sg + i) = (dma_addr_t)virt_to_bus(va);
-                sg_dma_len(sg + i) = sg[i].length;
+                BUG_ON(!sg_page(sg));
+                va = sg_virt(sg);
+                sg_dma_address(sg) = (dma_addr_t)virt_to_bus(va);
+                sg_dma_len(sg) = sg->length;
         }
 
         return nents;
diff --git a/block/blktrace.c b/block/blktrace.c
index d00ac3993c18..498a0a54a6aa 100644
--- a/block/blktrace.c
+++ b/block/blktrace.c
@@ -202,6 +202,7 @@ static void blk_remove_tree(struct dentry *dir)
 static struct dentry *blk_create_tree(const char *blk_name)
 {
         struct dentry *dir = NULL;
+        int created = 0;
 
         mutex_lock(&blk_tree_mutex);
 
@@ -209,13 +210,17 @@ static struct dentry *blk_create_tree(const char *blk_name)
                 blk_tree_root = debugfs_create_dir("block", NULL);
                 if (!blk_tree_root)
                         goto err;
+                created = 1;
         }
 
         dir = debugfs_create_dir(blk_name, blk_tree_root);
         if (dir)
                 root_users++;
-        else
-                blk_remove_root();
+        else {
+                /* Delete root only if we created it */
+                if (created)
+                        blk_remove_root();
+        }
 
 err:
         mutex_unlock(&blk_tree_mutex);
diff --git a/block/genhd.c b/block/genhd.c
index e609996f2e76..f2ac914160d1 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -715,6 +715,7 @@ struct gendisk *alloc_disk_node(int minors, int node_id)
                         disk->part = kmalloc_node(size,
                                 GFP_KERNEL | __GFP_ZERO, node_id);
                         if (!disk->part) {
+                                free_disk_stats(disk);
                                 kfree(disk);
                                 return NULL;
                         }
diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index 3b927be03850..8b919940b2ab 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -4080,23 +4080,7 @@ static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
         return queue_var_show(max_hw_sectors_kb, (page));
 }
 
-static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
-{
-        return queue_var_show(q->max_phys_segments, page);
-}
-
-static ssize_t queue_max_segments_store(struct request_queue *q,
-                                        const char *page, size_t count)
-{
-        unsigned long segments;
-        ssize_t ret = queue_var_store(&segments, page, count);
 
-        spin_lock_irq(q->queue_lock);
-        q->max_phys_segments = segments;
-        spin_unlock_irq(q->queue_lock);
-
-        return ret;
-}
 static struct queue_sysfs_entry queue_requests_entry = {
         .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
         .show = queue_requests_show,
@@ -4120,12 +4104,6 @@ static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
         .show = queue_max_hw_sectors_show,
 };
 
-static struct queue_sysfs_entry queue_max_segments_entry = {
-        .attr = {.name = "max_segments", .mode = S_IRUGO | S_IWUSR },
-        .show = queue_max_segments_show,
-        .store = queue_max_segments_store,
-};
-
 static struct queue_sysfs_entry queue_iosched_entry = {
         .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
         .show = elv_iosched_show,
@@ -4137,7 +4115,6 @@ static struct attribute *default_attrs[] = {
         &queue_ra_entry.attr,
         &queue_max_hw_sectors_entry.attr,
         &queue_max_sectors_entry.attr,
-        &queue_max_segments_entry.attr,
         &queue_iosched_entry.attr,
         NULL,
 };
diff --git a/drivers/mmc/card/queue.c b/drivers/mmc/card/queue.c
index 1b9c9b6da5b7..30cd13b13ac3 100644
--- a/drivers/mmc/card/queue.c
+++ b/drivers/mmc/card/queue.c
@@ -180,12 +180,13 @@ int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card, spinlock_t *lock
                 blk_queue_max_hw_segments(mq->queue, host->max_hw_segs);
                 blk_queue_max_segment_size(mq->queue, host->max_seg_size);
 
-                mq->sg = kzalloc(sizeof(struct scatterlist) *
+                mq->sg = kmalloc(sizeof(struct scatterlist) *
                         host->max_phys_segs, GFP_KERNEL);
                 if (!mq->sg) {
                         ret = -ENOMEM;
                         goto cleanup_queue;
                 }
+                sg_init_table(mq->sg, host->max_phys_segs);
         }
 
         init_MUTEX(&mq->thread_sem);
diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index 259735044148..416e000dfe81 100644
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -26,6 +26,16 @@
 
 #define SG_MAGIC        0x87654321
 
+/*
+ * We overload the LSB of the page pointer to indicate whether it's
+ * a valid sg entry, or whether it points to the start of a new scatterlist.
+ * Those low bits are there for everyone! (thanks mason :-)
+ */
+#define sg_is_chain(sg)         ((sg)->page_link & 0x01)
+#define sg_is_last(sg)          ((sg)->page_link & 0x02)
+#define sg_chain_ptr(sg)        \
+        ((struct scatterlist *) ((sg)->page_link & ~0x03))
+
 /**
  * sg_assign_page - Assign a given page to an SG entry
  * @sg:             SG entry
@@ -47,6 +57,7 @@ static inline void sg_assign_page(struct scatterlist *sg, struct page *page)
         BUG_ON((unsigned long) page & 0x03);
 #ifdef CONFIG_DEBUG_SG
         BUG_ON(sg->sg_magic != SG_MAGIC);
+        BUG_ON(sg_is_chain(sg));
 #endif
         sg->page_link = page_link | (unsigned long) page;
 }
@@ -73,7 +84,14 @@ static inline void sg_set_page(struct scatterlist *sg, struct page *page,
         sg->length = len;
 }
 
-#define sg_page(sg)     ((struct page *) ((sg)->page_link & ~0x3))
+static inline struct page *sg_page(struct scatterlist *sg)
+{
+#ifdef CONFIG_DEBUG_SG
+        BUG_ON(sg->sg_magic != SG_MAGIC);
+        BUG_ON(sg_is_chain(sg));
+#endif
+        return (struct page *)((sg)->page_link & ~0x3);
+}
 
 /**
  * sg_set_buf - Set sg entry to point at given data
@@ -88,16 +106,6 @@ static inline void sg_set_buf(struct scatterlist *sg, const void *buf,
         sg_set_page(sg, virt_to_page(buf), buflen, offset_in_page(buf));
 }
 
-/*
- * We overload the LSB of the page pointer to indicate whether it's
- * a valid sg entry, or whether it points to the start of a new scatterlist.
- * Those low bits are there for everyone! (thanks mason :-)
- */
-#define sg_is_chain(sg)         ((sg)->page_link & 0x01)
-#define sg_is_last(sg)          ((sg)->page_link & 0x02)
-#define sg_chain_ptr(sg)        \
-        ((struct scatterlist *) ((sg)->page_link & ~0x03))
-
 /**
  * sg_next - return the next scatterlist entry in a list
  * @sg:         The current sg entry
@@ -179,6 +187,13 @@ static inline void sg_chain(struct scatterlist *prv, unsigned int prv_nents,
 #ifndef ARCH_HAS_SG_CHAIN
         BUG();
 #endif
+
+        /*
+         * offset and length are unused for chain entry.  Clear them.
+         */
+        prv->offset = 0;
+        prv->length = 0;
+
         /*
          * Set lowest bit to indicate a link pointer, and make sure to clear
          * the termination bit if it happens to be set.