]> pilppa.org Git - linux-2.6-omap-h63xx.git/blobdiff - fs/splice.c
hpt366: simplify UltraDMA filtering (take 4)
[linux-2.6-omap-h63xx.git] / fs / splice.c
index 2fca6ebf4cc2d17ceb05ccb6cbe7f93ab3571a87..e7d7080de2f9799860a475a4df50a7742561d09f 100644 (file)
@@ -176,6 +176,7 @@ static const struct pipe_buf_operations user_page_pipe_buf_ops = {
 static ssize_t splice_to_pipe(struct pipe_inode_info *pipe,
                              struct splice_pipe_desc *spd)
 {
+       unsigned int spd_pages = spd->nr_pages;
        int ret, do_wakeup, page_nr;
 
        ret = 0;
@@ -244,17 +245,18 @@ static ssize_t splice_to_pipe(struct pipe_inode_info *pipe,
                pipe->waiting_writers--;
        }
 
-       if (pipe->inode)
+       if (pipe->inode) {
                mutex_unlock(&pipe->inode->i_mutex);
 
-       if (do_wakeup) {
-               smp_mb();
-               if (waitqueue_active(&pipe->wait))
-                       wake_up_interruptible(&pipe->wait);
-               kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
+               if (do_wakeup) {
+                       smp_mb();
+                       if (waitqueue_active(&pipe->wait))
+                               wake_up_interruptible(&pipe->wait);
+                       kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
+               }
        }
 
-       while (page_nr < spd->nr_pages)
+       while (page_nr < spd_pages)
                page_cache_release(spd->pages[page_nr++]);
 
        return ret;
@@ -272,7 +274,6 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
        struct page *page;
        pgoff_t index, end_index;
        loff_t isize;
-       size_t total_len;
        int error, page_nr;
        struct splice_pipe_desc spd = {
                .pages = pages,
@@ -289,18 +290,15 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
                nr_pages = PIPE_BUFFERS;
 
        /*
-        * Initiate read-ahead on this page range. however, don't call into
-        * read-ahead if this is a non-zero offset (we are likely doing small
-        * chunk splice and the page is already there) for a single page.
+        * Don't try to 2nd guess the read-ahead logic, call into
+        * page_cache_readahead() like the page cache reads would do.
         */
-       if (!loff || nr_pages > 1)
-               page_cache_readahead(mapping, &in->f_ra, in, index, nr_pages);
+       page_cache_readahead(mapping, &in->f_ra, in, index, nr_pages);
 
        /*
         * Now fill in the holes:
         */
        error = 0;
-       total_len = 0;
 
        /*
         * Lookup the (hopefully) full range of pages we need.
@@ -378,10 +376,11 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
                         * If in nonblock mode then dont block on waiting
                         * for an in-flight io page
                         */
-                       if (flags & SPLICE_F_NONBLOCK)
-                               break;
-
-                       lock_page(page);
+                       if (flags & SPLICE_F_NONBLOCK) {
+                               if (TestSetPageLocked(page))
+                                       break;
+                       } else
+                               lock_page(page);
 
                        /*
                         * page was truncated, stop here. if this isn't the
@@ -416,43 +415,47 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
 
                                break;
                        }
+               }
+fill_it:
+               /*
+                * i_size must be checked after PageUptodate.
+                */
+               isize = i_size_read(mapping->host);
+               end_index = (isize - 1) >> PAGE_CACHE_SHIFT;
+               if (unlikely(!isize || index > end_index))
+                       break;
+
+               /*
+                * if this is the last page, see if we need to shrink
+                * the length and stop
+                */
+               if (end_index == index) {
+                       unsigned int plen;
 
                        /*
-                        * i_size must be checked after ->readpage().
+                        * max good bytes in this page
                         */
-                       isize = i_size_read(mapping->host);
-                       end_index = (isize - 1) >> PAGE_CACHE_SHIFT;
-                       if (unlikely(!isize || index > end_index))
+                       plen = ((isize - 1) & ~PAGE_CACHE_MASK) + 1;
+                       if (plen <= loff)
                                break;
 
                        /*
-                        * if this is the last page, see if we need to shrink
-                        * the length and stop
+                        * force quit after adding this page
                         */
-                       if (end_index == index) {
-                               loff = PAGE_CACHE_SIZE - (isize & ~PAGE_CACHE_MASK);
-                               if (total_len + loff > isize)
-                                       break;
-                               /*
-                                * force quit after adding this page
-                                */
-                               len = this_len;
-                               this_len = min(this_len, loff);
-                               loff = 0;
-                       }
+                       this_len = min(this_len, plen - loff);
+                       len = this_len;
                }
-fill_it:
+
                partial[page_nr].offset = loff;
                partial[page_nr].len = this_len;
                len -= this_len;
-               total_len += this_len;
                loff = 0;
                spd.nr_pages++;
                index++;
        }
 
        /*
-        * Release any pages at the end, if we quit early. 'i' is how far
+        * Release any pages at the end, if we quit early. 'page_nr' is how far
         * we got, 'nr_pages' is how many pages are in the map.
         */
        while (page_nr < nr_pages)
@@ -479,10 +482,18 @@ ssize_t generic_file_splice_read(struct file *in, loff_t *ppos,
 {
        ssize_t spliced;
        int ret;
+       loff_t isize, left;
+
+       isize = i_size_read(in->f_mapping->host);
+       if (unlikely(*ppos >= isize))
+               return 0;
+
+       left = isize - *ppos;
+       if (unlikely(left < len))
+               len = left;
 
        ret = 0;
        spliced = 0;
-
        while (len) {
                ret = __generic_file_splice_read(in, ppos, pipe, len, flags);
 
@@ -576,76 +587,21 @@ static int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
        if (this_len + offset > PAGE_CACHE_SIZE)
                this_len = PAGE_CACHE_SIZE - offset;
 
-       /*
-        * Reuse buf page, if SPLICE_F_MOVE is set and we are doing a full
-        * page.
-        */
-       if ((sd->flags & SPLICE_F_MOVE) && this_len == PAGE_CACHE_SIZE) {
-               /*
-                * If steal succeeds, buf->page is now pruned from the
-                * pagecache and we can reuse it. The page will also be
-                * locked on successful return.
-                */
-               if (buf->ops->steal(pipe, buf))
-                       goto find_page;
-
-               page = buf->page;
-               if (add_to_page_cache(page, mapping, index, GFP_KERNEL)) {
-                       unlock_page(page);
-                       goto find_page;
-               }
-
-               page_cache_get(page);
-
-               if (!(buf->flags & PIPE_BUF_FLAG_LRU))
-                       lru_cache_add(page);
-       } else {
 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;
-               }
+       page = find_lock_page(mapping, index);
+       if (!page) {
+               ret = -ENOMEM;
+               page = page_cache_alloc_cold(mapping);
+               if (unlikely(!page))
+                       goto out_ret;
 
                /*
-                * We get here with the page locked. If the page is also
-                * uptodate, we don't need to do more. If it isn't, we
-                * may need to bring it in if we are not going to overwrite
-                * the full page.
+                * This will also lock the page
                 */
-               if (!PageUptodate(page)) {
-                       if (this_len < PAGE_CACHE_SIZE) {
-                               ret = mapping->a_ops->readpage(file, page);
-                               if (unlikely(ret))
-                                       goto out;
-
-                               lock_page(page);
-
-                               if (!PageUptodate(page)) {
-                                       /*
-                                        * Page got invalidated, repeat.
-                                        */
-                                       if (!page->mapping) {
-                                               unlock_page(page);
-                                               page_cache_release(page);
-                                               goto find_page;
-                                       }
-                                       ret = -EIO;
-                                       goto out;
-                               }
-                       } else
-                               SetPageUptodate(page);
-               }
+               ret = add_to_page_cache_lru(page, mapping, index,
+                                           GFP_KERNEL);
+               if (unlikely(ret))
+                       goto out;
        }
 
        ret = mapping->a_ops->prepare_write(file, page, offset, offset+this_len);
@@ -682,18 +638,24 @@ find_page:
        }
 
        ret = mapping->a_ops->commit_write(file, page, offset, offset+this_len);
-       if (!ret) {
+       if (ret) {
+               if (ret == AOP_TRUNCATED_PAGE) {
+                       page_cache_release(page);
+                       goto find_page;
+               }
+               if (ret < 0)
+                       goto out;
                /*
-                * Return the number of bytes written and mark page as
-                * accessed, we are now done!
+                * 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;
-               mark_page_accessed(page);
-               balance_dirty_pages_ratelimited(mapping);
-       } else if (ret == AOP_TRUNCATED_PAGE) {
-               page_cache_release(page);
-               goto find_page;
-       }
+       /*
+        * Return the number of bytes written and mark page as
+        * accessed, we are now done!
+        */
+       mark_page_accessed(page);
 out:
        page_cache_release(page);
        unlock_page(page);
@@ -706,9 +668,9 @@ out_ret:
  * key here is the 'actor' worker passed in that actually moves the data
  * to the wanted destination. See pipe_to_file/pipe_to_sendpage above.
  */
-static ssize_t __splice_from_pipe(struct pipe_inode_info *pipe,
-                                 struct file *out, loff_t *ppos, size_t len,
-                                 unsigned int flags, splice_actor *actor)
+ssize_t __splice_from_pipe(struct pipe_inode_info *pipe,
+                          struct file *out, loff_t *ppos, size_t len,
+                          unsigned int flags, splice_actor *actor)
 {
        int ret, do_wakeup, err;
        struct splice_desc sd;
@@ -802,6 +764,7 @@ static ssize_t __splice_from_pipe(struct pipe_inode_info *pipe,
 
        return ret;
 }
+EXPORT_SYMBOL(__splice_from_pipe);
 
 ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out,
                         loff_t *ppos, size_t len, unsigned int flags,
@@ -850,7 +813,10 @@ generic_file_splice_write_nolock(struct pipe_inode_info *pipe, struct file *out,
 
        ret = __splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_file);
        if (ret > 0) {
+               unsigned long nr_pages;
+
                *ppos += ret;
+               nr_pages = (ret + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
 
                /*
                 * If file or inode is SYNC and we actually wrote some data,
@@ -863,6 +829,7 @@ generic_file_splice_write_nolock(struct pipe_inode_info *pipe, struct file *out,
                        if (err)
                                ret = err;
                }
+               balance_dirty_pages_ratelimited_nr(mapping, nr_pages);
        }
 
        return ret;
@@ -901,7 +868,10 @@ generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
 
        ret = splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_file);
        if (ret > 0) {
+               unsigned long nr_pages;
+
                *ppos += ret;
+               nr_pages = (ret + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
 
                /*
                 * If file or inode is SYNC and we actually wrote some data,
@@ -916,6 +886,7 @@ generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
                        if (err)
                                ret = err;
                }
+               balance_dirty_pages_ratelimited_nr(mapping, nr_pages);
        }
 
        return ret;
@@ -970,7 +941,6 @@ static long do_splice_to(struct file *in, loff_t *ppos,
                         struct pipe_inode_info *pipe, size_t len,
                         unsigned int flags)
 {
-       loff_t isize, left;
        int ret;
 
        if (unlikely(!in->f_op || !in->f_op->splice_read))
@@ -983,14 +953,6 @@ static long do_splice_to(struct file *in, loff_t *ppos,
        if (unlikely(ret < 0))
                return ret;
 
-       isize = i_size_read(in->f_mapping->host);
-       if (unlikely(*ppos >= isize))
-               return 0;
-       
-       left = isize - *ppos;
-       if (unlikely(left < len))
-               len = left;
-
        return in->f_op->splice_read(in, ppos, pipe, len, flags);
 }
 
@@ -1106,8 +1068,6 @@ out_release:
        return ret;
 }
 
-EXPORT_SYMBOL(do_splice_direct);
-
 /*
  * After the inode slimming patch, i_pipe/i_bdev/i_cdev share the same
  * location, so checking ->i_pipe is not enough to verify that this is a