Merge branch 'splice' of git://brick.kernel.dk/data/git/linux-2.6-block

* 'splice' of git://brick.kernel.dk/data/git/linux-2.6-block:
  [PATCH] vmsplice: allow user to pass in gift pages
  [PATCH] pipe: enable atomic copying of pipe data to/from user space
  [PATCH] splice: call handle_ra_miss() on failure to lookup page
  [PATCH] Add ->splice_read/splice_write to def_blk_fops
  [PATCH] pipe: introduce ->pin() buffer operation
  [PATCH] splice: fix bugs in pipe_to_file()
  [PATCH] splice: fix bugs with stealing regular pipe pages

3 files changed, 230 insertions, 122 deletions

diff --git a/fs/block_dev.c b/fs/block_dev.c
index af88c43043d5..f5958f413bd1 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1104,6 +1104,8 @@ const struct file_operations def_blk_fops = {
         .readv          = generic_file_readv,
         .writev         = generic_file_write_nolock,
         .sendfile       = generic_file_sendfile,
+        .splice_read    = generic_file_splice_read,
+        .splice_write   = generic_file_splice_write,
 };
 
 int ioctl_by_bdev(struct block_device *bdev, unsigned cmd, unsigned long arg)
diff --git a/fs/pipe.c b/fs/pipe.c
index 7fefb10db8d9..3941a7f78b5d 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -55,7 +55,8 @@ void pipe_wait(struct pipe_inode_info *pipe)
 }
 
 static int
-pipe_iov_copy_from_user(void *to, struct iovec *iov, unsigned long len)
+pipe_iov_copy_from_user(void *to, struct iovec *iov, unsigned long len,
+                        int atomic)
 {
         unsigned long copy;
 
@@ -64,8 +65,13 @@ pipe_iov_copy_from_user(void *to, struct iovec *iov, unsigned long len)
                         iov++;
                 copy = min_t(unsigned long, len, iov->iov_len);
 
-                if (copy_from_user(to, iov->iov_base, copy))
-                        return -EFAULT;
+                if (atomic) {
+                        if (__copy_from_user_inatomic(to, iov->iov_base, copy))
+                                return -EFAULT;
+                } else {
+                        if (copy_from_user(to, iov->iov_base, copy))
+                                return -EFAULT;
+                }
                 to += copy;
                 len -= copy;
                 iov->iov_base += copy;
@@ -75,7 +81,8 @@ pipe_iov_copy_from_user(void *to, struct iovec *iov, unsigned long len)
 }
 
 static int
-pipe_iov_copy_to_user(struct iovec *iov, const void *from, unsigned long len)
+pipe_iov_copy_to_user(struct iovec *iov, const void *from, unsigned long len,
+                      int atomic)
 {
         unsigned long copy;
 
@@ -84,8 +91,13 @@ pipe_iov_copy_to_user(struct iovec *iov, const void *from, unsigned long len)
                         iov++;
                 copy = min_t(unsigned long, len, iov->iov_len);
 
-                if (copy_to_user(iov->iov_base, from, copy))
-                        return -EFAULT;
+                if (atomic) {
+                        if (__copy_to_user_inatomic(iov->iov_base, from, copy))
+                                return -EFAULT;
+                } else {
+                        if (copy_to_user(iov->iov_base, from, copy))
+                                return -EFAULT;
+                }
                 from += copy;
                 len -= copy;
                 iov->iov_base += copy;
@@ -94,13 +106,52 @@ pipe_iov_copy_to_user(struct iovec *iov, const void *from, unsigned long len)
         return 0;
 }
 
+/*
+ * Attempt to pre-fault in the user memory, so we can use atomic copies.
+ * Returns the number of bytes not faulted in.
+ */
+static int iov_fault_in_pages_write(struct iovec *iov, unsigned long len)
+{
+        while (!iov->iov_len)
+                iov++;
+
+        while (len > 0) {
+                unsigned long this_len;
+
+                this_len = min_t(unsigned long, len, iov->iov_len);
+                if (fault_in_pages_writeable(iov->iov_base, this_len))
+                        break;
+
+                len -= this_len;
+                iov++;
+        }
+
+        return len;
+}
+
+/*
+ * Pre-fault in the user memory, so we can use atomic copies.
+ */
+static void iov_fault_in_pages_read(struct iovec *iov, unsigned long len)
+{
+        while (!iov->iov_len)
+                iov++;
+
+        while (len > 0) {
+                unsigned long this_len;
+
+                this_len = min_t(unsigned long, len, iov->iov_len);
+                fault_in_pages_readable(iov->iov_base, this_len);
+                len -= this_len;
+                iov++;
+        }
+}
+
 static void anon_pipe_buf_release(struct pipe_inode_info *pipe,
                                   struct pipe_buffer *buf)
 {
         struct page *page = buf->page;
 
-        buf->flags &= ~PIPE_BUF_FLAG_STOLEN;
-
         /*
          * If nobody else uses this page, and we don't already have a
          * temporary page, let's keep track of it as a one-deep
@@ -112,38 +163,58 @@ static void anon_pipe_buf_release(struct pipe_inode_info *pipe,
                 page_cache_release(page);
 }
 
-static void * anon_pipe_buf_map(struct file *file, struct pipe_inode_info *pipe,
-                                struct pipe_buffer *buf)
+void *generic_pipe_buf_map(struct pipe_inode_info *pipe,
+                           struct pipe_buffer *buf, int atomic)
 {
+        if (atomic) {
+                buf->flags |= PIPE_BUF_FLAG_ATOMIC;
+                return kmap_atomic(buf->page, KM_USER0);
+        }
+
         return kmap(buf->page);
 }
 
-static void anon_pipe_buf_unmap(struct pipe_inode_info *pipe,
-                                struct pipe_buffer *buf)
+void generic_pipe_buf_unmap(struct pipe_inode_info *pipe,
+                            struct pipe_buffer *buf, void *map_data)
 {
-        kunmap(buf->page);
+        if (buf->flags & PIPE_BUF_FLAG_ATOMIC) {
+                buf->flags &= ~PIPE_BUF_FLAG_ATOMIC;
+                kunmap_atomic(map_data, KM_USER0);
+        } else
+                kunmap(buf->page);
 }
 
 static int anon_pipe_buf_steal(struct pipe_inode_info *pipe,
                                struct pipe_buffer *buf)
 {
-        buf->flags |= PIPE_BUF_FLAG_STOLEN;
-        return 0;
+        struct page *page = buf->page;
+
+        if (page_count(page) == 1) {
+                lock_page(page);
+                return 0;
+        }
+
+        return 1;
 }
 
-static void anon_pipe_buf_get(struct pipe_inode_info *info,
-                              struct pipe_buffer *buf)
+void generic_pipe_buf_get(struct pipe_inode_info *info, struct pipe_buffer *buf)
 {
         page_cache_get(buf->page);
 }
 
+int generic_pipe_buf_pin(struct pipe_inode_info *info, struct pipe_buffer *buf)
+{
+        return 0;
+}
+
 static struct pipe_buf_operations anon_pipe_buf_ops = {
         .can_merge = 1,
-        .map = anon_pipe_buf_map,
-        .unmap = anon_pipe_buf_unmap,
+        .map = generic_pipe_buf_map,
+        .unmap = generic_pipe_buf_unmap,
+        .pin = generic_pipe_buf_pin,
         .release = anon_pipe_buf_release,
         .steal = anon_pipe_buf_steal,
-        .get = anon_pipe_buf_get,
+        .get = generic_pipe_buf_get,
 };
 
 static ssize_t
@@ -174,22 +245,33 @@ pipe_readv(struct file *filp, const struct iovec *_iov,
                         struct pipe_buf_operations *ops = buf->ops;
                         void *addr;
                         size_t chars = buf->len;
-                        int error;
+                        int error, atomic;
 
                         if (chars > total_len)
                                 chars = total_len;
 
-                        addr = ops->map(filp, pipe, buf);
-                        if (IS_ERR(addr)) {
+                        error = ops->pin(pipe, buf);
+                        if (error) {
                                 if (!ret)
-                                        ret = PTR_ERR(addr);
+                                        error = ret;
                                 break;
                         }
-                        error = pipe_iov_copy_to_user(iov, addr + buf->offset, chars);
-                        ops->unmap(pipe, buf);
+
+                        atomic = !iov_fault_in_pages_write(iov, chars);
+redo:
+                        addr = ops->map(pipe, buf, atomic);
+                        error = pipe_iov_copy_to_user(iov, addr + buf->offset, chars, atomic);
+                        ops->unmap(pipe, buf, addr);
                         if (unlikely(error)) {
+                                /*
+                                 * Just retry with the slow path if we failed.
+                                 */
+                                if (atomic) {
+                                        atomic = 0;
+                                        goto redo;
+                                }
                                 if (!ret)
-                                        ret = -EFAULT;
+                                        ret = error;
                                 break;
                         }
                         ret += chars;
@@ -293,21 +375,28 @@ pipe_writev(struct file *filp, const struct iovec *_iov,
                 int offset = buf->offset + buf->len;
 
                 if (ops->can_merge && offset + chars <= PAGE_SIZE) {
+                        int error, atomic = 1;
                         void *addr;
-                        int error;
 
-                        addr = ops->map(filp, pipe, buf);
-                        if (IS_ERR(addr)) {
-                                error = PTR_ERR(addr);
+                        error = ops->pin(pipe, buf);
+                        if (error)
                                 goto out;
-                        }
+
+                        iov_fault_in_pages_read(iov, chars);
+redo1:
+                        addr = ops->map(pipe, buf, atomic);
                         error = pipe_iov_copy_from_user(offset + addr, iov,
-                                                        chars);
-                        ops->unmap(pipe, buf);
+                                                        chars, atomic);
+                        ops->unmap(pipe, buf, addr);
                         ret = error;
                         do_wakeup = 1;
-                        if (error)
+                        if (error) {
+                                if (atomic) {
+                                        atomic = 0;
+                                        goto redo1;
+                                }
                                 goto out;
+                        }
                         buf->len += chars;
                         total_len -= chars;
                         ret = chars;
@@ -330,7 +419,8 @@ pipe_writev(struct file *filp, const struct iovec *_iov,
                         int newbuf = (pipe->curbuf + bufs) & (PIPE_BUFFERS-1);
                         struct pipe_buffer *buf = pipe->bufs + newbuf;
                         struct page *page = pipe->tmp_page;
-                        int error;
+                        char *src;
+                        int error, atomic = 1;
 
                         if (!page) {
                                 page = alloc_page(GFP_HIGHUSER);
@@ -350,11 +440,27 @@ pipe_writev(struct file *filp, const struct iovec *_iov,
                         if (chars > total_len)
                                 chars = total_len;
 
-                        error = pipe_iov_copy_from_user(kmap(page), iov, chars);
-                        kunmap(page);
+                        iov_fault_in_pages_read(iov, chars);
+redo2:
+                        if (atomic)
+                                src = kmap_atomic(page, KM_USER0);
+                        else
+                                src = kmap(page);
+
+                        error = pipe_iov_copy_from_user(src, iov, chars,
+                                                        atomic);
+                        if (atomic)
+                                kunmap_atomic(src, KM_USER0);
+                        else
+                                kunmap(page);
+
                         if (unlikely(error)) {
+                                if (atomic) {
+                                        atomic = 0;
+                                        goto redo2;
+                                }
                                 if (!ret)
-                                        ret = -EFAULT;
+                                        ret = error;
                                 break;
                         }
                         ret += chars;
diff --git a/fs/splice.c b/fs/splice.c
index a46ddd28561e..b150493b6fc3 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -78,7 +78,7 @@ static int page_cache_pipe_buf_steal(struct pipe_inode_info *info,
                 return 1;
         }
 
-        buf->flags |= PIPE_BUF_FLAG_STOLEN | PIPE_BUF_FLAG_LRU;
+        buf->flags |= PIPE_BUF_FLAG_LRU;
         return 0;
 }
 
@@ -87,12 +87,11 @@ static void page_cache_pipe_buf_release(struct pipe_inode_info *info,
 {
         page_cache_release(buf->page);
         buf->page = NULL;
-        buf->flags &= ~(PIPE_BUF_FLAG_STOLEN | PIPE_BUF_FLAG_LRU);
+        buf->flags &= ~PIPE_BUF_FLAG_LRU;
 }
 
-static void *page_cache_pipe_buf_map(struct file *file,
-                                     struct pipe_inode_info *info,
-                                     struct pipe_buffer *buf)
+static int page_cache_pipe_buf_pin(struct pipe_inode_info *info,
+                                   struct pipe_buffer *buf)
 {
         struct page *page = buf->page;
         int err;
@@ -118,64 +117,44 @@ static void *page_cache_pipe_buf_map(struct file *file,
                 }
 
                 /*
-                 * Page is ok afterall, fall through to mapping.
+                 * Page is ok afterall, we are done.
                  */
                 unlock_page(page);
         }
 
-        return kmap(page);
+        return 0;
 error:
         unlock_page(page);
-        return ERR_PTR(err);
-}
-
-static void page_cache_pipe_buf_unmap(struct pipe_inode_info *info,
-                                      struct pipe_buffer *buf)
-{
-        kunmap(buf->page);
-}
-
-static void *user_page_pipe_buf_map(struct file *file,
-                                    struct pipe_inode_info *pipe,
-                                    struct pipe_buffer *buf)
-{
-        return kmap(buf->page);
-}
-
-static void user_page_pipe_buf_unmap(struct pipe_inode_info *pipe,
-                                     struct pipe_buffer *buf)
-{
-        kunmap(buf->page);
-}
-
-static void page_cache_pipe_buf_get(struct pipe_inode_info *info,
-                                    struct pipe_buffer *buf)
-{
-        page_cache_get(buf->page);
+        return err;
 }
 
 static struct pipe_buf_operations page_cache_pipe_buf_ops = {
         .can_merge = 0,
-        .map = page_cache_pipe_buf_map,
-        .unmap = page_cache_pipe_buf_unmap,
+        .map = generic_pipe_buf_map,
+        .unmap = generic_pipe_buf_unmap,
+        .pin = page_cache_pipe_buf_pin,
         .release = page_cache_pipe_buf_release,
         .steal = page_cache_pipe_buf_steal,
-        .get = page_cache_pipe_buf_get,
+        .get = generic_pipe_buf_get,
 };
 
 static int user_page_pipe_buf_steal(struct pipe_inode_info *pipe,
                                     struct pipe_buffer *buf)
 {
-        return 1;
+        if (!(buf->flags & PIPE_BUF_FLAG_GIFT))
+                return 1;
+
+        return 0;
 }
 
 static struct pipe_buf_operations user_page_pipe_buf_ops = {
         .can_merge = 0,
-        .map = user_page_pipe_buf_map,
-        .unmap = user_page_pipe_buf_unmap,
+        .map = generic_pipe_buf_map,
+        .unmap = generic_pipe_buf_unmap,
+        .pin = generic_pipe_buf_pin,
         .release = page_cache_pipe_buf_release,
         .steal = user_page_pipe_buf_steal,
-        .get = page_cache_pipe_buf_get,
+        .get = generic_pipe_buf_get,
 };
 
 /*
@@ -210,6 +189,9 @@ static ssize_t splice_to_pipe(struct pipe_inode_info *pipe,
                         buf->offset = spd->partial[page_nr].offset;
                         buf->len = spd->partial[page_nr].len;
                         buf->ops = spd->ops;
+                        if (spd->flags & SPLICE_F_GIFT)
+                                buf->flags |= PIPE_BUF_FLAG_GIFT;
+
                         pipe->nrbufs++;
                         page_nr++;
                         ret += buf->len;
@@ -326,6 +308,12 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
                 page = find_get_page(mapping, index);
                 if (!page) {
                         /*
+                         * Make sure the read-ahead engine is notified
+                         * about this failure.
+                         */
+                        handle_ra_miss(mapping, &in->f_ra, index);
+
+                        /*
                          * page didn't exist, allocate one.
                          */
                         page = page_cache_alloc_cold(mapping);
@@ -517,26 +505,16 @@ static int pipe_to_sendpage(struct pipe_inode_info *info,
 {
         struct file *file = sd->file;
         loff_t pos = sd->pos;
-        ssize_t ret;
-        void *ptr;
-        int more;
-
-        /*
-         * Sub-optimal, but we are limited by the pipe ->map. We don't
-         * need a kmap'ed buffer here, we just want to make sure we
-         * have the page pinned if the pipe page originates from the
-         * page cache.
-         */
-        ptr = buf->ops->map(file, info, buf);
-        if (IS_ERR(ptr))
-                return PTR_ERR(ptr);
+        int ret, more;
 
-        more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len;
+        ret = buf->ops->pin(info, buf);
+        if (!ret) {
+                more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len;
 
-        ret = file->f_op->sendpage(file, buf->page, buf->offset, sd->len,
-                                   &pos, more);
+                ret = file->f_op->sendpage(file, buf->page, buf->offset,
+                                           sd->len, &pos, more);
+        }
 
-        buf->ops->unmap(info, buf);
         return ret;
 }
 
@@ -569,15 +547,14 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf,
         unsigned int offset, this_len;
         struct page *page;
         pgoff_t index;
-        char *src;
         int ret;
 
         /*
          * make sure the data in this buffer is uptodate
          */
-        src = buf->ops->map(file, info, buf);
-        if (IS_ERR(src))
-                return PTR_ERR(src);
+        ret = buf->ops->pin(info, buf);
+        if (unlikely(ret))
+                return ret;
 
         index = sd->pos >> PAGE_CACHE_SHIFT;
         offset = sd->pos & ~PAGE_CACHE_MASK;
@@ -587,9 +564,10 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf,
                 this_len = PAGE_CACHE_SIZE - offset;
 
         /*
-         * Reuse buf page, if SPLICE_F_MOVE is set.
+         * Reuse buf page, if SPLICE_F_MOVE is set and we are doing a full
+         * page.
          */
-        if (sd->flags & SPLICE_F_MOVE) {
+        if ((sd->flags & SPLICE_F_MOVE) && this_len == PAGE_CACHE_SIZE) {
                 /*
                  * If steal succeeds, buf->page is now pruned from the vm
                  * side (LRU and page cache) and we can reuse it. The page
@@ -599,8 +577,12 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf,
                         goto find_page;
 
                 page = buf->page;
-                if (add_to_page_cache(page, mapping, index, gfp_mask))
+                if (add_to_page_cache(page, mapping, index, gfp_mask)) {
+                        unlock_page(page);
                         goto find_page;
+                }
+
+                page_cache_get(page);
 
                 if (!(buf->flags & PIPE_BUF_FLAG_LRU))
                         lru_cache_add(page);
@@ -660,34 +642,36 @@ find_page:
         } else if (ret)
                 goto out;
 
-        if (!(buf->flags & PIPE_BUF_FLAG_STOLEN)) {
-                char *dst = kmap_atomic(page, KM_USER0);
+        if (buf->page != page) {
+                /*
+                 * Careful, ->map() uses KM_USER0!
+                 */
+                char *src = buf->ops->map(info, buf, 1);
+                char *dst = kmap_atomic(page, KM_USER1);
 
                 memcpy(dst + offset, src + buf->offset, this_len);
                 flush_dcache_page(page);
-                kunmap_atomic(dst, KM_USER0);
+                kunmap_atomic(dst, KM_USER1);
+                buf->ops->unmap(info, buf, src);
         }
 
         ret = mapping->a_ops->commit_write(file, page, offset, offset+this_len);
-        if (ret == AOP_TRUNCATED_PAGE) {
+        if (!ret) {
+                /*
+                 * Return the number of bytes written and mark page as
+                 * accessed, we are now done!
+                 */
+                ret = this_len;
+                mark_page_accessed(page);
+                balance_dirty_pages_ratelimited(mapping);
+        } else if (ret == AOP_TRUNCATED_PAGE) {
                 page_cache_release(page);
                 goto find_page;
-        } else if (ret)
-                goto out;
-
-        /*
-         * Return the number of bytes written.
-         */
-        ret = this_len;
-        mark_page_accessed(page);
-        balance_dirty_pages_ratelimited(mapping);
+        }
 out:
-        if (!(buf->flags & PIPE_BUF_FLAG_STOLEN))
-                page_cache_release(page);
-
+        page_cache_release(page);
         unlock_page(page);
 out_nomem:
-        buf->ops->unmap(info, buf);
         return ret;
 }
 
@@ -1095,7 +1079,7 @@ static long do_splice(struct file *in, loff_t __user *off_in,
  */
 static int get_iovec_page_array(const struct iovec __user *iov,
                                 unsigned int nr_vecs, struct page **pages,
-                                struct partial_page *partial)
+                                struct partial_page *partial, int aligned)
 {
         int buffers = 0, error = 0;
 
@@ -1135,6 +1119,15 @@ static int get_iovec_page_array(const struct iovec __user *iov,
                  * in the user pages.
                  */
                 off = (unsigned long) base & ~PAGE_MASK;
+
+                /*
+                 * If asked for alignment, the offset must be zero and the
+                 * length a multiple of the PAGE_SIZE.
+                 */
+                error = -EINVAL;
+                if (aligned && (off || len & ~PAGE_MASK))
+                        break;
+
                 npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
                 if (npages > PIPE_BUFFERS - buffers)
                         npages = PIPE_BUFFERS - buffers;
@@ -1228,7 +1221,8 @@ static long do_vmsplice(struct file *file, const struct iovec __user *iov,
         else if (unlikely(!nr_segs))
                 return 0;
 
-        spd.nr_pages = get_iovec_page_array(iov, nr_segs, pages, partial);
+        spd.nr_pages = get_iovec_page_array(iov, nr_segs, pages, partial,
+                                            flags & SPLICE_F_GIFT);
         if (spd.nr_pages <= 0)
                 return spd.nr_pages;
 
@@ -1336,6 +1330,12 @@ static int link_pipe(struct pipe_inode_info *ipipe,
                                 obuf = opipe->bufs + nbuf;
                                 *obuf = *ibuf;
 
+                                /*
+                                 * Don't inherit the gift flag, we need to
+                                 * prevent multiple steals of this page.
+                                 */
+                                obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
+
                                 if (obuf->len > len)
                                         obuf->len = len;