Merge branch 'for-2.6.26' of git://git.kernel.dk/linux-2.6-block

* 'for-2.6.26' of git://git.kernel.dk/linux-2.6-block:
  block: fix blk_register_queue() return value
  block: fix memory hotplug and bouncing in block layer
  block: replace remaining __FUNCTION__ occurrences
  Kconfig: clean up block/Kconfig help descriptions
  cciss: fix warning oops on rmmod of driver
  cciss: Fix race between disk-adding code and interrupt handler
  block: move the padding adjustment to blk_rq_map_sg
  block: add bio_copy_user_iov support to blk_rq_map_user_iov
  block: convert bio_copy_user to bio_copy_user_iov
  loop: manage partitions in disk image
  cdrom: use kmalloced buffers instead of buffers on stack
  cdrom: make unregister_cdrom() return void
  cdrom: use list_head for cdrom_device_info list
  cdrom: protect cdrom_device_info list by mutex
  cdrom: cleanup hardcoded error-code
  cdrom: remove ifdef CONFIG_SYSCTL

4 files changed, 81 insertions, 49 deletions

diff --git a/block/Kconfig b/block/Kconfig
index 7db9a411649d..3e97f2bc446f 100644
--- a/block/Kconfig
+++ b/block/Kconfig
@@ -5,14 +5,18 @@ menuconfig BLOCK
        bool "Enable the block layer" if EMBEDDED
        default y
        help
-	 This permits the block layer to be removed from the kernel if it's not
-	 needed (on some embedded devices for example).  If this option is
-	 disabled, then blockdev files will become unusable and some
-	 filesystems (such as ext3) will become unavailable.
+	 Provide block layer support for the kernel.
 
-	 This option will also disable SCSI character devices and USB storage
-	 since they make use of various block layer definitions and
-	 facilities.
+	 Disable this option to remove the block layer support from the
+	 kernel. This may be useful for embedded devices.
+
+	 If this option is disabled:
+
+	   - block device files will become unusable
+	   - some filesystems (such as ext3) will become unavailable.
+
+	 Also, SCSI character devices and USB storage will be disabled since
+	 they make use of various block layer definitions and facilities.
 
 	 Say Y here unless you know you really don't want to mount disks and
 	 suchlike.
@@ -23,9 +27,20 @@ config LBD
 	bool "Support for Large Block Devices"
 	depends on !64BIT
 	help
-	  Say Y here if you want to attach large (bigger than 2TB) discs to
-	  your machine, or if you want to have a raid or loopback device
-	  bigger than 2TB.  Otherwise say N.
+	  Enable block devices of size 2TB and larger.
+
+	  This option is required to support the full capacity of large
+	  (2TB+) block devices, including RAID, disk, Network Block Device,
+	  Logical Volume Manager (LVM) and loopback.
+
+	  For example, RAID devices are frequently bigger than the capacity
+	  of the largest individual hard drive.
+
+	  This option is not required if you have individual disk drives
+	  which total 2TB+ and you are not aggregating the capacity into
+	  a large block device (e.g. using RAID or LVM).
+
+	  If unsure, say N.
 
 config BLK_DEV_IO_TRACE
 	bool "Support for tracing block io actions"
@@ -33,19 +48,21 @@ config BLK_DEV_IO_TRACE
 	select RELAY
 	select DEBUG_FS
 	help
-	  Say Y here, if you want to be able to trace the block layer actions
+	  Say Y here if you want to be able to trace the block layer actions
 	  on a given queue. Tracing allows you to see any traffic happening
-	  on a block device queue. For more information (and the user space
-	  support tools needed), fetch the blktrace app from:
+	  on a block device queue. For more information (and the userspace
+	  support tools needed), fetch the blktrace tools from:
 
 	  git://git.kernel.dk/blktrace.git
 
+	  If unsure, say N.
+
 config LSF
 	bool "Support for Large Single Files"
 	depends on !64BIT
 	help
-	  Say Y here if you want to be able to handle very large files (bigger
-	  than 2TB), otherwise say N.
+	  Say Y here if you want to be able to handle very large files (2TB
+	  and larger), otherwise say N.
 
 	  If unsure, say Y.
 
@@ -53,14 +70,16 @@ config BLK_DEV_BSG
 	bool "Block layer SG support v4 (EXPERIMENTAL)"
 	depends on EXPERIMENTAL
 	---help---
-	Saying Y here will enable generic SG (SCSI generic) v4 support
-	for any block device.
-
-	Unlike SG v3 (aka block/scsi_ioctl.c drivers/scsi/sg.c), SG v4
-	can handle complicated SCSI commands: tagged variable length cdbs
-	with bidirectional data transfers and generic request/response
-	protocols (e.g. Task Management Functions and SMP in Serial
-	Attached SCSI).
+	  Saying Y here will enable generic SG (SCSI generic) v4 support
+	  for any block device.
+
+	  Unlike SG v3 (aka block/scsi_ioctl.c drivers/scsi/sg.c), SG v4
+	  can handle complicated SCSI commands: tagged variable length cdbs
+	  with bidirectional data transfers and generic request/response
+	  protocols (e.g. Task Management Functions and SMP in Serial
+	  Attached SCSI).
+
+	  If unsure, say N.
 
 endif # BLOCK
 
diff --git a/block/blk-map.c b/block/blk-map.c
index c07d9c8317f4..3c942bd6422a 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -5,6 +5,7 @@
 #include <linux/module.h>
 #include <linux/bio.h>
 #include <linux/blkdev.h>
+#include <scsi/sg.h>		/* for struct sg_iovec */
 
 #include "blk.h"
 
@@ -140,25 +141,8 @@ int blk_rq_map_user(struct request_queue *q, struct request *rq,
 		ubuf += ret;
 	}
 
-	/*
-	 * __blk_rq_map_user() copies the buffers if starting address
-	 * or length isn't aligned to dma_pad_mask.  As the copied
-	 * buffer is always page aligned, we know that there's enough
-	 * room for padding.  Extend the last bio and update
-	 * rq->data_len accordingly.
-	 *
-	 * On unmap, bio_uncopy_user() will use unmodified
-	 * bio_map_data pointed to by bio->bi_private.
-	 */
-	if (len & q->dma_pad_mask) {
-		unsigned int pad_len = (q->dma_pad_mask & ~len) + 1;
-		struct bio *tail = rq->biotail;
-
-		tail->bi_io_vec[tail->bi_vcnt - 1].bv_len += pad_len;
-		tail->bi_size += pad_len;
-
-		rq->extra_len += pad_len;
-	}
+	if (!bio_flagged(bio, BIO_USER_MAPPED))
+		rq->cmd_flags |= REQ_COPY_USER;
 
 	rq->buffer = rq->data = NULL;
 	return 0;
@@ -194,15 +178,26 @@ int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
 			struct sg_iovec *iov, int iov_count, unsigned int len)
 {
 	struct bio *bio;
+	int i, read = rq_data_dir(rq) == READ;
+	int unaligned = 0;
 
 	if (!iov || iov_count <= 0)
 		return -EINVAL;
 
-	/* we don't allow misaligned data like bio_map_user() does.  If the
-	 * user is using sg, they're expected to know the alignment constraints
-	 * and respect them accordingly */
-	bio = bio_map_user_iov(q, NULL, iov, iov_count,
-				rq_data_dir(rq) == READ);
+	for (i = 0; i < iov_count; i++) {
+		unsigned long uaddr = (unsigned long)iov[i].iov_base;
+
+		if (uaddr & queue_dma_alignment(q)) {
+			unaligned = 1;
+			break;
+		}
+	}
+
+	if (unaligned || (q->dma_pad_mask & len))
+		bio = bio_copy_user_iov(q, iov, iov_count, read);
+	else
+		bio = bio_map_user_iov(q, NULL, iov, iov_count, read);
+
 	if (IS_ERR(bio))
 		return PTR_ERR(bio);
 
@@ -212,6 +207,9 @@ int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
 		return -EINVAL;
 	}
 
+	if (!bio_flagged(bio, BIO_USER_MAPPED))
+		rq->cmd_flags |= REQ_COPY_USER;
+
 	bio_get(bio);
 	blk_rq_bio_prep(q, rq, bio);
 	rq->buffer = rq->data = NULL;
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 0f58616bcd7f..b5c5c4a9e3f0 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -220,6 +220,15 @@ new_segment:
 		bvprv = bvec;
 	} /* segments in rq */
 
+
+	if (unlikely(rq->cmd_flags & REQ_COPY_USER) &&
+	    (rq->data_len & q->dma_pad_mask)) {
+		unsigned int pad_len = (q->dma_pad_mask & ~rq->data_len) + 1;
+
+		sg->length += pad_len;
+		rq->extra_len += pad_len;
+	}
+
 	if (q->dma_drain_size && q->dma_drain_needed(rq)) {
 		if (rq->cmd_flags & REQ_RW)
 			memset(q->dma_drain_buffer, 0, q->dma_drain_size);
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index 54d0db116153..fc41d83be22b 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -276,9 +276,12 @@ int blk_register_queue(struct gendisk *disk)
 
 	struct request_queue *q = disk->queue;
 
-	if (!q || !q->request_fn)
+	if (WARN_ON(!q))
 		return -ENXIO;
 
+	if (!q->request_fn)
+		return 0;
+
 	ret = kobject_add(&q->kobj, kobject_get(&disk->dev.kobj),
 			  "%s", "queue");
 	if (ret < 0)
@@ -300,7 +303,10 @@ void blk_unregister_queue(struct gendisk *disk)
 {
 	struct request_queue *q = disk->queue;
 
-	if (q && q->request_fn) {
+	if (WARN_ON(!q))
+		return;
+
+	if (q->request_fn) {
 		elv_unregister_queue(q);
 
 		kobject_uevent(&q->kobj, KOBJ_REMOVE);