fix mismerge in ll_rw_blk.c

7 files changed, 404 insertions, 108 deletions

diff --git a/drivers/block/ll_rw_blk.c b/drivers/block/ll_rw_blk.c
index 3c818544475e..0c7599563b65 100644
--- a/drivers/block/ll_rw_blk.c
+++ b/drivers/block/ll_rw_blk.c
@@ -284,6 +284,7 @@ static inline void rq_init(request_queue_t *q, struct request *rq)
         rq->special = NULL;
         rq->data_len = 0;
         rq->data = NULL;
+        rq->nr_phys_segments = 0;
         rq->sense = NULL;
         rq->end_io = NULL;
         rq->end_io_data = NULL;
@@ -2115,7 +2116,7 @@ EXPORT_SYMBOL(blk_insert_request);
 /**
  * blk_rq_map_user - map user data to a request, for REQ_BLOCK_PC usage
  * @q:          request queue where request should be inserted
- * @rw:         READ or WRITE data
+ * @rq:         request structure to fill
  * @ubuf:       the user buffer
  * @len:        length of user data
  *
@@ -2132,21 +2133,19 @@ EXPORT_SYMBOL(blk_insert_request);
  *    original bio must be passed back in to blk_rq_unmap_user() for proper
  *    unmapping.
  */
-struct request *blk_rq_map_user(request_queue_t *q, int rw, void __user *ubuf,
-                                unsigned int len)
+int blk_rq_map_user(request_queue_t *q, struct request *rq, void __user *ubuf,
+                    unsigned int len)
 {
         unsigned long uaddr;
-        struct request *rq;
         struct bio *bio;
+        int reading;
 
         if (len > (q->max_sectors << 9))
-                return ERR_PTR(-EINVAL);
-        if ((!len && ubuf) || (len && !ubuf))
-                return ERR_PTR(-EINVAL);
+                return -EINVAL;
+        if (!len || !ubuf)
+                return -EINVAL;
 
-        rq = blk_get_request(q, rw, __GFP_WAIT);
-        if (!rq)
-                return ERR_PTR(-ENOMEM);
+        reading = rq_data_dir(rq) == READ;
 
         /*
          * if alignment requirement is satisfied, map in user pages for
@@ -2154,9 +2153,9 @@ struct request *blk_rq_map_user(request_queue_t *q, int rw, void __user *ubuf,
          */
         uaddr = (unsigned long) ubuf;
         if (!(uaddr & queue_dma_alignment(q)) && !(len & queue_dma_alignment(q)))
-                bio = bio_map_user(q, NULL, uaddr, len, rw == READ);
+                bio = bio_map_user(q, NULL, uaddr, len, reading);
         else
-                bio = bio_copy_user(q, uaddr, len, rw == READ);
+                bio = bio_copy_user(q, uaddr, len, reading);
 
         if (!IS_ERR(bio)) {
                 rq->bio = rq->biotail = bio;
@@ -2164,28 +2163,70 @@ struct request *blk_rq_map_user(request_queue_t *q, int rw, void __user *ubuf,
 
                 rq->buffer = rq->data = NULL;
                 rq->data_len = len;
-                return rq;
+                return 0;
         }
 
         /*
          * bio is the err-ptr
          */
-        blk_put_request(rq);
-        return (struct request *) bio;
+        return PTR_ERR(bio);
 }
 
 EXPORT_SYMBOL(blk_rq_map_user);
 
 /**
+ * blk_rq_map_user_iov - map user data to a request, for REQ_BLOCK_PC usage
+ * @q:          request queue where request should be inserted
+ * @rq:         request to map data to
+ * @iov:        pointer to the iovec
+ * @iov_count:  number of elements in the iovec
+ *
+ * Description:
+ *    Data will be mapped directly for zero copy io, if possible. Otherwise
+ *    a kernel bounce buffer is used.
+ *
+ *    A matching blk_rq_unmap_user() must be issued at the end of io, while
+ *    still in process context.
+ *
+ *    Note: The mapped bio may need to be bounced through blk_queue_bounce()
+ *    before being submitted to the device, as pages mapped may be out of
+ *    reach. It's the callers responsibility to make sure this happens. The
+ *    original bio must be passed back in to blk_rq_unmap_user() for proper
+ *    unmapping.
+ */
+int blk_rq_map_user_iov(request_queue_t *q, struct request *rq,
+                        struct sg_iovec *iov, int iov_count)
+{
+        struct bio *bio;
+
+        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);
+        if (IS_ERR(bio))
+                return PTR_ERR(bio);
+
+        rq->bio = rq->biotail = bio;
+        blk_rq_bio_prep(q, rq, bio);
+        rq->buffer = rq->data = NULL;
+        rq->data_len = bio->bi_size;
+        return 0;
+}
+
+EXPORT_SYMBOL(blk_rq_map_user_iov);
+
+/**
  * blk_rq_unmap_user - unmap a request with user data
- * @rq:         request to be unmapped
- * @bio:        bio for the request
+ * @bio:        bio to be unmapped
  * @ulen:       length of user buffer
  *
  * Description:
- *    Unmap a request previously mapped by blk_rq_map_user().
+ *    Unmap a bio previously mapped by blk_rq_map_user().
  */
-int blk_rq_unmap_user(struct request *rq, struct bio *bio, unsigned int ulen)
+int blk_rq_unmap_user(struct bio *bio, unsigned int ulen)
 {
         int ret = 0;
 
@@ -2196,31 +2237,89 @@ int blk_rq_unmap_user(struct request *rq, struct bio *bio, unsigned int ulen)
                         ret = bio_uncopy_user(bio);
         }
 
-        blk_put_request(rq);
-        return ret;
+        return 0;
 }
 
 EXPORT_SYMBOL(blk_rq_unmap_user);
 
 /**
+ * blk_rq_map_kern - map kernel data to a request, for REQ_BLOCK_PC usage
+ * @q:          request queue where request should be inserted
+ * @rq:         request to fill
+ * @kbuf:       the kernel buffer
+ * @len:        length of user data
+ * @gfp_mask:   memory allocation flags
+ */
+int blk_rq_map_kern(request_queue_t *q, struct request *rq, void *kbuf,
+                    unsigned int len, unsigned int gfp_mask)
+{
+        struct bio *bio;
+
+        if (len > (q->max_sectors << 9))
+                return -EINVAL;
+        if (!len || !kbuf)
+                return -EINVAL;
+
+        bio = bio_map_kern(q, kbuf, len, gfp_mask);
+        if (IS_ERR(bio))
+                return PTR_ERR(bio);
+
+        if (rq_data_dir(rq) == WRITE)
+                bio->bi_rw |= (1 << BIO_RW);
+
+        rq->bio = rq->biotail = bio;
+        blk_rq_bio_prep(q, rq, bio);
+
+        rq->buffer = rq->data = NULL;
+        rq->data_len = len;
+        return 0;
+}
+
+EXPORT_SYMBOL(blk_rq_map_kern);
+
+/**
+ * blk_execute_rq_nowait - insert a request into queue for execution
+ * @q:          queue to insert the request in
+ * @bd_disk:    matching gendisk
+ * @rq:         request to insert
+ * @at_head:    insert request at head or tail of queue
+ * @done:       I/O completion handler
+ *
+ * Description:
+ *    Insert a fully prepared request at the back of the io scheduler queue
+ *    for execution.  Don't wait for completion.
+ */
+void blk_execute_rq_nowait(request_queue_t *q, struct gendisk *bd_disk,
+                           struct request *rq, int at_head,
+                           void (*done)(struct request *))
+{
+        int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK;
+
+        rq->rq_disk = bd_disk;
+        rq->flags |= REQ_NOMERGE;
+        rq->end_io = done;
+        elv_add_request(q, rq, where, 1);
+        generic_unplug_device(q);
+}
+
+/**
  * blk_execute_rq - insert a request into queue for execution
  * @q:          queue to insert the request in
  * @bd_disk:    matching gendisk
  * @rq:         request to insert
+ * @at_head:    insert request at head or tail of queue
  *
  * Description:
  *    Insert a fully prepared request at the back of the io scheduler queue
- *    for execution.
+ *    for execution and wait for completion.
  */
 int blk_execute_rq(request_queue_t *q, struct gendisk *bd_disk,
-                   struct request *rq)
+                   struct request *rq, int at_head)
 {
         DECLARE_COMPLETION(wait);
         char sense[SCSI_SENSE_BUFFERSIZE];
         int err = 0;
 
-        rq->rq_disk = bd_disk;
-
         /*
          * we need an extra reference to the request, so we can look at
          * it after io completion
@@ -2233,11 +2332,8 @@ int blk_execute_rq(request_queue_t *q, struct gendisk *bd_disk,
                 rq->sense_len = 0;
         }
 
-        rq->flags |= REQ_NOMERGE;
         rq->waiting = &wait;
-        rq->end_io = blk_end_sync_rq;
-        elv_add_request(q, rq, ELEVATOR_INSERT_BACK, 1);
-        generic_unplug_device(q);
+        blk_execute_rq_nowait(q, bd_disk, rq, at_head, blk_end_sync_rq);
         wait_for_completion(&wait);
         rq->waiting = NULL;
 
@@ -2277,6 +2373,44 @@ int blkdev_issue_flush(struct block_device *bdev, sector_t *error_sector)
 
 EXPORT_SYMBOL(blkdev_issue_flush);
 
+/**
+ * blkdev_scsi_issue_flush_fn - issue flush for SCSI devices
+ * @q:          device queue
+ * @disk:       gendisk
+ * @error_sector:       error offset
+ *
+ * Description:
+ *    Devices understanding the SCSI command set, can use this function as
+ *    a helper for issuing a cache flush. Note: driver is required to store
+ *    the error offset (in case of error flushing) in ->sector of struct
+ *    request.
+ */
+int blkdev_scsi_issue_flush_fn(request_queue_t *q, struct gendisk *disk,
+                               sector_t *error_sector)
+{
+        struct request *rq = blk_get_request(q, WRITE, __GFP_WAIT);
+        int ret;
+
+        rq->flags |= REQ_BLOCK_PC | REQ_SOFTBARRIER;
+        rq->sector = 0;
+        memset(rq->cmd, 0, sizeof(rq->cmd));
+        rq->cmd[0] = 0x35;
+        rq->cmd_len = 12;
+        rq->data = NULL;
+        rq->data_len = 0;
+        rq->timeout = 60 * HZ;
+
+        ret = blk_execute_rq(q, disk, rq, 0);
+
+        if (ret && error_sector)
+                *error_sector = rq->sector;
+
+        blk_put_request(rq);
+        return ret;
+}
+
+EXPORT_SYMBOL(blkdev_scsi_issue_flush_fn);
+
 static void drive_stat_acct(struct request *rq, int nr_sectors, int new_io)
 {
         int rw = rq_data_dir(rq);
diff --git a/drivers/block/scsi_ioctl.c b/drivers/block/scsi_ioctl.c
index 681871ca5d60..abb2df249fd3 100644
--- a/drivers/block/scsi_ioctl.c
+++ b/drivers/block/scsi_ioctl.c
@@ -216,7 +216,7 @@ static int sg_io(struct file *file, request_queue_t *q,
                 struct gendisk *bd_disk, struct sg_io_hdr *hdr)
 {
         unsigned long start_time;
-        int reading, writing;
+        int writing = 0, ret = 0;
         struct request *rq;
         struct bio *bio;
         char sense[SCSI_SENSE_BUFFERSIZE];
@@ -231,38 +231,48 @@ static int sg_io(struct file *file, request_queue_t *q,
         if (verify_command(file, cmd))
                 return -EPERM;
 
-        /*
-         * we'll do that later
-         */
-        if (hdr->iovec_count)
-                return -EOPNOTSUPP;
-
         if (hdr->dxfer_len > (q->max_sectors << 9))
                 return -EIO;
 
-        reading = writing = 0;
-        if (hdr->dxfer_len) {
+        if (hdr->dxfer_len)
                 switch (hdr->dxfer_direction) {
                 default:
                         return -EINVAL;
                 case SG_DXFER_TO_FROM_DEV:
-                        reading = 1;
-                        /* fall through */
                 case SG_DXFER_TO_DEV:
                         writing = 1;
                         break;
                 case SG_DXFER_FROM_DEV:
-                        reading = 1;
                         break;
                 }
 
-                rq = blk_rq_map_user(q, writing ? WRITE : READ, hdr->dxferp,
-                                     hdr->dxfer_len);
+        rq = blk_get_request(q, writing ? WRITE : READ, GFP_KERNEL);
+        if (!rq)
+                return -ENOMEM;
+
+        if (hdr->iovec_count) {
+                const int size = sizeof(struct sg_iovec) * hdr->iovec_count;
+                struct sg_iovec *iov;
+
+                iov = kmalloc(size, GFP_KERNEL);
+                if (!iov) {
+                        ret = -ENOMEM;
+                        goto out;
+                }
+
+                if (copy_from_user(iov, hdr->dxferp, size)) {
+                        kfree(iov);
+                        ret = -EFAULT;
+                        goto out;
+                }
+
+                ret = blk_rq_map_user_iov(q, rq, iov, hdr->iovec_count);
+                kfree(iov);
+        } else if (hdr->dxfer_len)
+                ret = blk_rq_map_user(q, rq, hdr->dxferp, hdr->dxfer_len);
 
-                if (IS_ERR(rq))
-                        return PTR_ERR(rq);
-        } else
-                rq = blk_get_request(q, READ, __GFP_WAIT);
+        if (ret)
+                goto out;
 
         /*
          * fill in request structure
@@ -298,7 +308,7 @@ static int sg_io(struct file *file, request_queue_t *q,
          * (if he doesn't check that is his problem).
          * N.B. a non-zero SCSI status is _not_ necessarily an error.
          */
-        blk_execute_rq(q, bd_disk, rq);
+        blk_execute_rq(q, bd_disk, rq, 0);
 
         /* write to all output members */
         hdr->status = 0xff & rq->errors;
@@ -320,12 +330,14 @@ static int sg_io(struct file *file, request_queue_t *q,
                         hdr->sb_len_wr = len;
         }
 
-        if (blk_rq_unmap_user(rq, bio, hdr->dxfer_len))
-                return -EFAULT;
+        if (blk_rq_unmap_user(bio, hdr->dxfer_len))
+                ret = -EFAULT;
 
         /* may not have succeeded, but output values written to control
          * structure (struct sg_io_hdr).  */
-        return 0;
+out:
+        blk_put_request(rq);
+        return ret;
 }
 
 #define OMAX_SB_LEN 16          /* For backward compatibility */
@@ -408,7 +420,7 @@ static int sg_scsi_ioctl(struct file *file, request_queue_t *q,
         rq->data_len = bytes;
         rq->flags |= REQ_BLOCK_PC;
 
-        blk_execute_rq(q, bd_disk, rq);
+        blk_execute_rq(q, bd_disk, rq, 0);
         err = rq->errors & 0xff;        /* only 8 bit SCSI status */
         if (err) {
                 if (rq->sense_len && rq->sense) {
@@ -561,7 +573,7 @@ int scsi_cmd_ioctl(struct file *file, struct gendisk *bd_disk, unsigned int cmd,
                         rq->cmd[0] = GPCMD_START_STOP_UNIT;
                         rq->cmd[4] = 0x02 + (close != 0);
                         rq->cmd_len = 6;
-                        err = blk_execute_rq(q, bd_disk, rq);
+                        err = blk_execute_rq(q, bd_disk, rq, 0);
                         blk_put_request(rq);
                         break;
                 default:
diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
index beaa561f2ed8..153960348414 100644
--- a/drivers/cdrom/cdrom.c
+++ b/drivers/cdrom/cdrom.c
@@ -2097,6 +2097,10 @@ static int cdrom_read_cdda_bpc(struct cdrom_device_info *cdi, __u8 __user *ubuf,
         if (!q)
                 return -ENXIO;
 
+        rq = blk_get_request(q, READ, GFP_KERNEL);
+        if (!rq)
+                return -ENOMEM;
+
         cdi->last_sense = 0;
 
         while (nframes) {
@@ -2108,9 +2112,9 @@ static int cdrom_read_cdda_bpc(struct cdrom_device_info *cdi, __u8 __user *ubuf,
 
                 len = nr * CD_FRAMESIZE_RAW;
 
-                rq = blk_rq_map_user(q, READ, ubuf, len);
-                if (IS_ERR(rq))
-                        return PTR_ERR(rq);
+                ret = blk_rq_map_user(q, rq, ubuf, len);
+                if (ret)
+                        break;
 
                 memset(rq->cmd, 0, sizeof(rq->cmd));
                 rq->cmd[0] = GPCMD_READ_CD;
@@ -2132,13 +2136,13 @@ static int cdrom_read_cdda_bpc(struct cdrom_device_info *cdi, __u8 __user *ubuf,
                 if (rq->bio)
                         blk_queue_bounce(q, &rq->bio);
 
-                if (blk_execute_rq(q, cdi->disk, rq)) {
+                if (blk_execute_rq(q, cdi->disk, rq, 0)) {
                         struct request_sense *s = rq->sense;
                         ret = -EIO;
                         cdi->last_sense = s->sense_key;
                 }
 
-                if (blk_rq_unmap_user(rq, bio, len))
+                if (blk_rq_unmap_user(bio, len))
                         ret = -EFAULT;
 
                 if (ret)
@@ -2149,6 +2153,7 @@ static int cdrom_read_cdda_bpc(struct cdrom_device_info *cdi, __u8 __user *ubuf,
                 ubuf += len;
         }
 
+        blk_put_request(rq);
         return ret;
 }
 
diff --git a/drivers/ide/ide-disk.c b/drivers/ide/ide-disk.c
index c9d3a00a3c0c..234f5de3e929 100644
--- a/drivers/ide/ide-disk.c
+++ b/drivers/ide/ide-disk.c
@@ -754,7 +754,7 @@ static int idedisk_issue_flush(request_queue_t *q, struct gendisk *disk,
 
         idedisk_prepare_flush(q, rq);
 
-        ret = blk_execute_rq(q, disk, rq);
+        ret = blk_execute_rq(q, disk, rq, 0);
 
         /*
          * if we failed and caller wants error offset, get it
diff --git a/fs/bio.c b/fs/bio.c
index 1f2d4649b188..e49cf7dd2e92 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -25,6 +25,7 @@
 #include <linux/module.h>
 #include <linux/mempool.h>
 #include <linux/workqueue.h>
+#include <scsi/sg.h>            /* for struct sg_iovec */
 
 #define BIO_POOL_SIZE 256
 
@@ -546,22 +547,34 @@ out_bmd:
         return ERR_PTR(ret);
 }
 
-static struct bio *__bio_map_user(request_queue_t *q, struct block_device *bdev,
-                                  unsigned long uaddr, unsigned int len,
-                                  int write_to_vm)
+static struct bio *__bio_map_user_iov(request_queue_t *q,
+                                      struct block_device *bdev,
+                                      struct sg_iovec *iov, int iov_count,
+                                      int write_to_vm)
 {
-        unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
-        unsigned long start = uaddr >> PAGE_SHIFT;
-        const int nr_pages = end - start;
-        int ret, offset, i;
+        int i, j;
+        int nr_pages = 0;
         struct page **pages;
         struct bio *bio;
+        int cur_page = 0;
+        int ret, offset;
 
-        /*
-         * transfer and buffer must be aligned to at least hardsector
-         * size for now, in the future we can relax this restriction
-         */
-        if ((uaddr & queue_dma_alignment(q)) || (len & queue_dma_alignment(q)))
+        for (i = 0; i < iov_count; i++) {
+                unsigned long uaddr = (unsigned long)iov[i].iov_base;
+                unsigned long len = iov[i].iov_len;
+                unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
+                unsigned long start = uaddr >> PAGE_SHIFT;
+
+                nr_pages += end - start;
+                /*
+                 * transfer and buffer must be aligned to at least hardsector
+                 * size for now, in the future we can relax this restriction
+                 */
+                if ((uaddr & queue_dma_alignment(q)) || (len & queue_dma_alignment(q)))
+                        return ERR_PTR(-EINVAL);
+        }
+
+        if (!nr_pages)
                 return ERR_PTR(-EINVAL);
 
         bio = bio_alloc(GFP_KERNEL, nr_pages);
@@ -573,42 +586,54 @@ static struct bio *__bio_map_user(request_queue_t *q, struct block_device *bdev,
         if (!pages)
                 goto out;
 
-        down_read(&current->mm->mmap_sem);
-        ret = get_user_pages(current, current->mm, uaddr, nr_pages,
-                                                write_to_vm, 0, pages, NULL);
-        up_read(&current->mm->mmap_sem);
-
-        if (ret < nr_pages)
-                goto out;
-
-        bio->bi_bdev = bdev;
-
-        offset = uaddr & ~PAGE_MASK;
-        for (i = 0; i < nr_pages; i++) {
-                unsigned int bytes = PAGE_SIZE - offset;
-
-                if (len <= 0)
-                        break;
-
-                if (bytes > len)
-                        bytes = len;
+        memset(pages, 0, nr_pages * sizeof(struct page *));
+
+        for (i = 0; i < iov_count; i++) {
+                unsigned long uaddr = (unsigned long)iov[i].iov_base;
+                unsigned long len = iov[i].iov_len;
+                unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
+                unsigned long start = uaddr >> PAGE_SHIFT;
+                const int local_nr_pages = end - start;
+                const int page_limit = cur_page + local_nr_pages;
+                
+                down_read(&current->mm->mmap_sem);
+                ret = get_user_pages(current, current->mm, uaddr,
+                                     local_nr_pages,
+                                     write_to_vm, 0, &pages[cur_page], NULL);
+                up_read(&current->mm->mmap_sem);
+
+                if (ret < local_nr_pages)
+                        goto out_unmap;
+
+
+                offset = uaddr & ~PAGE_MASK;
+                for (j = cur_page; j < page_limit; j++) {
+                        unsigned int bytes = PAGE_SIZE - offset;
+
+                        if (len <= 0)
+                                break;
+                        
+                        if (bytes > len)
+                                bytes = len;
+
+                        /*
+                         * sorry...
+                         */
+                        if (__bio_add_page(q, bio, pages[j], bytes, offset) < bytes)
+                                break;
+
+                        len -= bytes;
+                        offset = 0;
+                }
 
+                cur_page = j;
                 /*
-                 * sorry...
+                 * release the pages we didn't map into the bio, if any
                  */
-                if (__bio_add_page(q, bio, pages[i], bytes, offset) < bytes)
-                        break;
-
-                len -= bytes;
-                offset = 0;
+                while (j < page_limit)
+                        page_cache_release(pages[j++]);
         }
 
-        /*
-         * release the pages we didn't map into the bio, if any
-         */
-        while (i < nr_pages)
-                page_cache_release(pages[i++]);
-
         kfree(pages);
 
         /*
@@ -617,9 +642,17 @@ static struct bio *__bio_map_user(request_queue_t *q, struct block_device *bdev,
         if (!write_to_vm)
                 bio->bi_rw |= (1 << BIO_RW);
 
+        bio->bi_bdev = bdev;
         bio->bi_flags |= (1 << BIO_USER_MAPPED);
         return bio;
-out:
+
+ out_unmap:
+        for (i = 0; i < nr_pages; i++) {
+                if(!pages[i])
+                        break;
+                page_cache_release(pages[i]);
+        }
+ out:
         kfree(pages);
         bio_put(bio);
         return ERR_PTR(ret);
@@ -639,9 +672,33 @@ out:
 struct bio *bio_map_user(request_queue_t *q, struct block_device *bdev,
                          unsigned long uaddr, unsigned int len, int write_to_vm)
 {
+        struct sg_iovec iov;
+
+        iov.iov_base = (__user void *)uaddr;
+        iov.iov_len = len;
+
+        return bio_map_user_iov(q, bdev, &iov, 1, write_to_vm);
+}
+
+/**
+ *      bio_map_user_iov - map user sg_iovec table into bio
+ *      @q: the request_queue_t for the bio
+ *      @bdev: destination block device
+ *      @iov:   the iovec.
+ *      @iov_count: number of elements in the iovec
+ *      @write_to_vm: bool indicating writing to pages or not
+ *
+ *      Map the user space address into a bio suitable for io to a block
+ *      device. Returns an error pointer in case of error.
+ */
+struct bio *bio_map_user_iov(request_queue_t *q, struct block_device *bdev,
+                             struct sg_iovec *iov, int iov_count,
+                             int write_to_vm)
+{
         struct bio *bio;
+        int len = 0, i;
 
-        bio = __bio_map_user(q, bdev, uaddr, len, write_to_vm);
+        bio = __bio_map_user_iov(q, bdev, iov, iov_count, write_to_vm);
 
         if (IS_ERR(bio))
                 return bio;
@@ -654,6 +711,9 @@ struct bio *bio_map_user(request_queue_t *q, struct block_device *bdev,
          */
         bio_get(bio);
 
+        for (i = 0; i < iov_count; i++)
+                len += iov[i].iov_len;
+
         if (bio->bi_size == len)
                 return bio;
 
@@ -698,6 +758,82 @@ void bio_unmap_user(struct bio *bio)
         bio_put(bio);
 }
 
+static int bio_map_kern_endio(struct bio *bio, unsigned int bytes_done, int err)
+{
+        if (bio->bi_size)
+                return 1;
+
+        bio_put(bio);
+        return 0;
+}
+
+
+static struct bio *__bio_map_kern(request_queue_t *q, void *data,
+                                  unsigned int len, unsigned int gfp_mask)
+{
+        unsigned long kaddr = (unsigned long)data;
+        unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
+        unsigned long start = kaddr >> PAGE_SHIFT;
+        const int nr_pages = end - start;
+        int offset, i;
+        struct bio *bio;
+
+        bio = bio_alloc(gfp_mask, nr_pages);
+        if (!bio)
+                return ERR_PTR(-ENOMEM);
+
+        offset = offset_in_page(kaddr);
+        for (i = 0; i < nr_pages; i++) {
+                unsigned int bytes = PAGE_SIZE - offset;
+
+                if (len <= 0)
+                        break;
+
+                if (bytes > len)
+                        bytes = len;
+
+                if (__bio_add_page(q, bio, virt_to_page(data), bytes,
+                                   offset) < bytes)
+                        break;
+
+                data += bytes;
+                len -= bytes;
+                offset = 0;
+        }
+
+        bio->bi_end_io = bio_map_kern_endio;
+        return bio;
+}
+
+/**
+ *      bio_map_kern    -       map kernel address into bio
+ *      @q: the request_queue_t for the bio
+ *      @data: pointer to buffer to map
+ *      @len: length in bytes
+ *      @gfp_mask: allocation flags for bio allocation
+ *
+ *      Map the kernel address into a bio suitable for io to a block
+ *      device. Returns an error pointer in case of error.
+ */
+struct bio *bio_map_kern(request_queue_t *q, void *data, unsigned int len,
+                         unsigned int gfp_mask)
+{
+        struct bio *bio;
+
+        bio = __bio_map_kern(q, data, len, gfp_mask);
+        if (IS_ERR(bio))
+                return bio;
+
+        if (bio->bi_size == len)
+                return bio;
+
+        /*
+         * Don't support partial mappings.
+         */
+        bio_put(bio);
+        return ERR_PTR(-EINVAL);
+}
+
 /*
  * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions
  * for performing direct-IO in BIOs.
@@ -1085,6 +1221,7 @@ EXPORT_SYMBOL(bio_add_page);
 EXPORT_SYMBOL(bio_get_nr_vecs);
 EXPORT_SYMBOL(bio_map_user);
 EXPORT_SYMBOL(bio_unmap_user);
+EXPORT_SYMBOL(bio_map_kern);
 EXPORT_SYMBOL(bio_pair_release);
 EXPORT_SYMBOL(bio_split);
 EXPORT_SYMBOL(bio_split_pool);
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 36ef29fa0d8b..4fda06da56c1 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -295,7 +295,13 @@ extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
 extern int bio_get_nr_vecs(struct block_device *);
 extern struct bio *bio_map_user(struct request_queue *, struct block_device *,
                                 unsigned long, unsigned int, int);
+struct sg_iovec;
+extern struct bio *bio_map_user_iov(struct request_queue *,
+                                    struct block_device *,
+                                    struct sg_iovec *, int, int);
 extern void bio_unmap_user(struct bio *);
+extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
+                                unsigned int);
 extern void bio_set_pages_dirty(struct bio *bio);
 extern void bio_check_pages_dirty(struct bio *bio);
 extern struct bio *bio_copy_user(struct request_queue *, unsigned long, unsigned int, int);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 19bd8e7e11bf..aefa26fbae8a 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -563,10 +563,12 @@ extern void blk_sync_queue(struct request_queue *q);
 extern void __blk_stop_queue(request_queue_t *q);
 extern void blk_run_queue(request_queue_t *);
 extern void blk_queue_activity_fn(request_queue_t *, activity_fn *, void *);
-extern struct request *blk_rq_map_user(request_queue_t *, int, void __user *, unsigned int);
-extern int blk_rq_unmap_user(struct request *, struct bio *, unsigned int);
-extern int blk_execute_rq(request_queue_t *, struct gendisk *, struct request *);
-
+extern int blk_rq_map_user(request_queue_t *, struct request *, void __user *, unsigned int);
+extern int blk_rq_unmap_user(struct bio *, unsigned int);
+extern int blk_rq_map_kern(request_queue_t *, struct request *, void *, unsigned int, unsigned int);
+extern int blk_rq_map_user_iov(request_queue_t *, struct request *, struct sg_iovec *, int);
+extern int blk_execute_rq(request_queue_t *, struct gendisk *,
+                          struct request *, int);
 static inline request_queue_t *bdev_get_queue(struct block_device *bdev)
 {
         return bdev->bd_disk->queue;