x86: code clarification patch to Kprobes arch code

[linux-2.6] / fs / splice.c

diff --git a/fs/splice.c b/fs/splice.c
index e95a362..1577a73 100644 (file)
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -254,11 +254,16 @@ ssize_t splice_to_pipe(struct pipe_inode_info *pipe,
        }
 
        while (page_nr < spd_pages)
-               page_cache_release(spd->pages[page_nr++]);
+               spd->spd_release(spd, page_nr++);
 
        return ret;
 }
 
+static void spd_release_page(struct splice_pipe_desc *spd, unsigned int i)
+{
+       page_cache_release(spd->pages[i]);
+}
+
 static int
 __generic_file_splice_read(struct file *in, loff_t *ppos,
                           struct pipe_inode_info *pipe, size_t len,
@@ -277,6 +282,7 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
                .partial = partial,
                .flags = flags,
                .ops = &page_cache_pipe_buf_ops,
+               .spd_release = spd_release_page,
        };
 
        index = *ppos >> PAGE_CACHE_SHIFT;
@@ -447,7 +453,7 @@ fill_it:
         */
        while (page_nr < nr_pages)
                page_cache_release(pages[page_nr++]);
-       in->f_ra.prev_index = index;
+       in->f_ra.prev_pos = (loff_t)index << PAGE_CACHE_SHIFT;
 
        if (spd.nr_pages)
                return splice_to_pipe(pipe, &spd);
@@ -563,7 +569,7 @@ static int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
        struct address_space *mapping = file->f_mapping;
        unsigned int offset, this_len;
        struct page *page;
-       pgoff_t index;
+       void *fsdata;
        int ret;
 
        /*
@@ -573,49 +579,16 @@ static int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
        if (unlikely(ret))
                return ret;
 
-       index = sd->pos >> PAGE_CACHE_SHIFT;
        offset = sd->pos & ~PAGE_CACHE_MASK;
 
        this_len = sd->len;
        if (this_len + offset > PAGE_CACHE_SIZE)
                this_len = PAGE_CACHE_SIZE - offset;
 
-find_page:
-       page = find_lock_page(mapping, index);
-       if (!page) {
-               ret = -ENOMEM;
-               page = page_cache_alloc_cold(mapping);
-               if (unlikely(!page))
-                       goto out_ret;
-
-               /*
-                * This will also lock the page
-                */
-               ret = add_to_page_cache_lru(page, mapping, index,
-                                           GFP_KERNEL);
-               if (unlikely(ret))
-                       goto out_release;
-       }
-
-       ret = mapping->a_ops->prepare_write(file, page, offset, offset+this_len);
-       if (unlikely(ret)) {
-               loff_t isize = i_size_read(mapping->host);
-
-               if (ret != AOP_TRUNCATED_PAGE)
-                       unlock_page(page);
-               page_cache_release(page);
-               if (ret == AOP_TRUNCATED_PAGE)
-                       goto find_page;
-
-               /*
-                * prepare_write() may have instantiated a few blocks
-                * outside i_size.  Trim these off again.
-                */
-               if (sd->pos + this_len > isize)
-                       vmtruncate(mapping->host, isize);
-
-               goto out_ret;
-       }
+       ret = pagecache_write_begin(file, mapping, sd->pos, this_len,
+                               AOP_FLAG_UNINTERRUPTIBLE, &page, &fsdata);
+       if (unlikely(ret))
+               goto out;
 
        if (buf->page != page) {
                /*
@@ -629,31 +602,9 @@ find_page:
                kunmap_atomic(dst, KM_USER1);
                buf->ops->unmap(pipe, buf, src);
        }
-
-       ret = mapping->a_ops->commit_write(file, page, offset, offset+this_len);
-       if (ret) {
-               if (ret == AOP_TRUNCATED_PAGE) {
-                       page_cache_release(page);
-                       goto find_page;
-               }
-               if (ret < 0)
-                       goto out;
-               /*
-                * Partial write has happened, so 'ret' already initialized by
-                * number of bytes written, Where is nothing we have to do here.
-                */
-       } else
-               ret = this_len;
-       /*
-        * Return the number of bytes written and mark page as
-        * accessed, we are now done!
-        */
-       mark_page_accessed(page);
+       ret = pagecache_write_end(file, mapping, sd->pos, this_len, this_len,
+                               page, fsdata);
 out:
-       unlock_page(page);
-out_release:
-       page_cache_release(page);
-out_ret:
        return ret;
 }
 
@@ -879,13 +830,18 @@ generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
 {
        struct address_space *mapping = out->f_mapping;
        struct inode *inode = mapping->host;
+       int killsuid, killpriv;
        ssize_t ret;
-       int err;
+       int err = 0;
 
-       err = should_remove_suid(out->f_path.dentry);
-       if (unlikely(err)) {
+       killpriv = security_inode_need_killpriv(out->f_path.dentry);
+       killsuid = should_remove_suid(out->f_path.dentry);
+       if (unlikely(killsuid || killpriv)) {
                mutex_lock(&inode->i_mutex);
-               err = __remove_suid(out->f_path.dentry, err);
+               if (killpriv)
+                       err = security_inode_killpriv(out->f_path.dentry);
+               if (!err && killsuid)
+                       err = __remove_suid(out->f_path.dentry, killsuid);
                mutex_unlock(&inode->i_mutex);
                if (err)
                        return err;
@@ -958,10 +914,6 @@ static long do_splice_from(struct pipe_inode_info *pipe, struct file *out,
        if (unlikely(ret < 0))
                return ret;
 
-       ret = security_file_permission(out, MAY_WRITE);
-       if (unlikely(ret < 0))
-               return ret;
-
        return out->f_op->splice_write(pipe, out, ppos, len, flags);
 }
 
@@ -984,10 +936,6 @@ static long do_splice_to(struct file *in, loff_t *ppos,
        if (unlikely(ret < 0))
                return ret;
 
-       ret = security_file_permission(in, MAY_READ);
-       if (unlikely(ret < 0))
-               return ret;
-
        return in->f_op->splice_read(in, ppos, pipe, len, flags);
 }
 
@@ -1083,7 +1031,11 @@ ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd,
                        goto out_release;
        }
 
+done:
        pipe->nrbufs = pipe->curbuf = 0;
+       if (bytes > 0)
+               file_accessed(in);
+
        return bytes;
 
 out_release:
@@ -1099,16 +1051,11 @@ out_release:
                        buf->ops = NULL;
                }
        }
-       pipe->nrbufs = pipe->curbuf = 0;
 
-       /*
-        * If we transferred some data, return the number of bytes:
-        */
-       if (bytes > 0)
-               return bytes;
-
-       return ret;
+       if (!bytes)
+               bytes = ret;
 
+       goto done;
 }
 EXPORT_SYMBOL(splice_direct_to_actor);
 
@@ -1390,10 +1337,10 @@ static int pipe_to_user(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
        if (copy_to_user(sd->u.userptr, src + buf->offset, sd->len))
                ret = -EFAULT;
 
+       buf->ops->unmap(pipe, buf, src);
 out:
        if (ret > 0)
                sd->u.userptr += ret;
-       buf->ops->unmap(pipe, buf, src);
        return ret;
 }
 
@@ -1490,6 +1437,7 @@ static long vmsplice_to_pipe(struct file *file, const struct iovec __user *iov,
                .partial = partial,
                .flags = flags,
                .ops = &user_page_pipe_buf_ops,
+               .spd_release = spd_release_page,
        };
 
        pipe = pipe_info(file->f_path.dentry->d_inode);