2.6.25

 block

diff --git a/block/blk-map.c b/block/blk-map.c
new file mode 100644
index 0000000..c07d9c8
--- /dev/null
+++ b/block/blk-map.c
@@ -0,0 +1,283 @@
+/*
+ * Functions related to mapping data to requests
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/bio.h>
+#include <linux/blkdev.h>
+
+#include "blk.h"
+
+int blk_rq_append_bio(struct request_queue *q, struct request *rq,
+            struct bio *bio)
+{
+   if (!rq->bio)
+      blk_rq_bio_prep(q, rq, bio);
+   else if (!ll_back_merge_fn(q, rq, bio))
+      return -EINVAL;
+   else {
+      rq->biotail->bi_next = bio;
+      rq->biotail = bio;
+
+      rq->data_len += bio->bi_size;
+   }
+   return 0;
+}
+EXPORT_SYMBOL(blk_rq_append_bio);
+
+static int __blk_rq_unmap_user(struct bio *bio)
+{
+   int ret = 0;
+
+   if (bio) {
+      if (bio_flagged(bio, BIO_USER_MAPPED))
+         bio_unmap_user(bio);
+      else
+         ret = bio_uncopy_user(bio);
+   }
+
+   return ret;
+}
+
+static int __blk_rq_map_user(struct request_queue *q, struct request *rq,
+              void __user *ubuf, unsigned int len)
+{
+   unsigned long uaddr;
+   unsigned int alignment;
+   struct bio *bio, *orig_bio;
+   int reading, ret;
+
+   reading = rq_data_dir(rq) == READ;
+
+   /*
+    * if alignment requirement is satisfied, map in user pages for
+    * direct dma. else, set up kernel bounce buffers
+    */
+   uaddr = (unsigned long) ubuf;
+   alignment = queue_dma_alignment(q) | q->dma_pad_mask;
+   if (!(uaddr & alignment) && !(len & alignment))
+      bio = bio_map_user(q, NULL, uaddr, len, reading);
+   else
+      bio = bio_copy_user(q, uaddr, len, reading);
+
+   if (IS_ERR(bio))
+      return PTR_ERR(bio);
+
+   orig_bio = bio;
+   blk_queue_bounce(q, &bio);
+
+   /*
+    * We link the bounce buffer in and could have to traverse it
+    * later so we have to get a ref to prevent it from being freed
+    */
+   bio_get(bio);
+
+   ret = blk_rq_append_bio(q, rq, bio);
+   if (!ret)
+      return bio->bi_size;
+
+   /* if it was boucned we must call the end io function */
+   bio_endio(bio, 0);
+   __blk_rq_unmap_user(orig_bio);
+   bio_put(bio);
+   return ret;
+}
+
+/**
+ * blk_rq_map_user - map user data to a request, for REQ_BLOCK_PC usage
+ * @q:      request queue where request should be inserted
+ * @rq:      request structure to fill
+ * @ubuf:   the user buffer
+ * @len:   length of user data
+ *
+ * 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(struct request_queue *q, struct request *rq,
+          void __user *ubuf, unsigned long len)
+{
+   unsigned long bytes_read = 0;
+   struct bio *bio = NULL;
+   int ret;
+
+   if (len > (q->max_hw_sectors << 9))
+      return -EINVAL;
+   if (!len || !ubuf)
+      return -EINVAL;
+
+   while (bytes_read != len) {
+      unsigned long map_len, end, start;
+
+      map_len = min_t(unsigned long, len - bytes_read, BIO_MAX_SIZE);
+      end = ((unsigned long)ubuf + map_len + PAGE_SIZE - 1)
+                        >> PAGE_SHIFT;
+      start = (unsigned long)ubuf >> PAGE_SHIFT;
+
+      /*
+       * A bad offset could cause us to require BIO_MAX_PAGES + 1
+       * pages. If this happens we just lower the requested
+       * mapping len by a page so that we can fit
+       */
+      if (end - start > BIO_MAX_PAGES)
+         map_len -= PAGE_SIZE;
+
+      ret = __blk_rq_map_user(q, rq, ubuf, map_len);
+      if (ret < 0)
+         goto unmap_rq;
+      if (!bio)
+         bio = rq->bio;
+      bytes_read += ret;
+      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;
+   }
+
+   rq->buffer = rq->data = NULL;
+   return 0;
+unmap_rq:
+   blk_rq_unmap_user(bio);
+   rq->bio = NULL;
+   return ret;
+}
+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
+ * @len:   I/O byte count
+ *
+ * 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(struct request_queue *q, struct request *rq,
+         struct sg_iovec *iov, int iov_count, unsigned int len)
+{
+   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);
+
+   if (bio->bi_size != len) {
+      bio_endio(bio, 0);
+      bio_unmap_user(bio);
+      return -EINVAL;
+   }
+
+   bio_get(bio);
+   blk_rq_bio_prep(q, rq, bio);
+   rq->buffer = rq->data = NULL;
+   return 0;
+}
+
+/**
+ * blk_rq_unmap_user - unmap a request with user data
+ * @bio:          start of bio list
+ *
+ * Description:
+ *    Unmap a rq previously mapped by blk_rq_map_user(). The caller must
+ *    supply the original rq->bio from the blk_rq_map_user() return, since
+ *    the io completion may have changed rq->bio.
+ */
+int blk_rq_unmap_user(struct bio *bio)
+{
+   struct bio *mapped_bio;
+   int ret = 0, ret2;
+
+   while (bio) {
+      mapped_bio = bio;
+      if (unlikely(bio_flagged(bio, BIO_BOUNCED)))
+         mapped_bio = bio->bi_private;
+
+      ret2 = __blk_rq_unmap_user(mapped_bio);
+      if (ret2 && !ret)
+         ret = ret2;
+
+      mapped_bio = bio;
+      bio = bio->bi_next;
+      bio_put(mapped_bio);
+   }
+
+   return ret;
+}
+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(struct request_queue *q, struct request *rq, void *kbuf,
+          unsigned int len, gfp_t gfp_mask)
+{
+   struct bio *bio;
+
+   if (len > (q->max_hw_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);
+
+   blk_rq_bio_prep(q, rq, bio);
+   blk_queue_bounce(q, &rq->bio);
+   rq->buffer = rq->data = NULL;
+   return 0;
+}
+EXPORT_SYMBOL(blk_rq_map_kern);