mm: clean up buffered write code

Rename some variables and fix some types.

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/filemap.c b/mm/filemap.c
index 4bf7d1a..f74d052 100644 (file)
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1838,16 +1838,15 @@ generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov,
                size_t count, ssize_t written)
 {
        struct file *file = iocb->ki_filp;
-       struct address_space * mapping = file->f_mapping;
+       struct address_space *mapping = file->f_mapping;
        const struct address_space_operations *a_ops = mapping->a_ops;
        struct inode    *inode = mapping->host;
        long            status = 0;
        struct page     *page;
        struct page     *cached_page = NULL;
-       size_t          bytes;
        struct pagevec  lru_pvec;
        const struct iovec *cur_iov = iov; /* current iovec */
-       size_t          iov_base = 0;      /* offset in the current iovec */
+       size_t          iov_offset = 0;    /* offset in the current iovec */
        char __user     *buf;
 
        pagevec_init(&lru_pvec, 0);
@@ -1858,31 +1857,33 @@ generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov,
        if (likely(nr_segs == 1))
                buf = iov->iov_base + written;
        else {
-               filemap_set_next_iovec(&cur_iov, &iov_base, written);
-               buf = cur_iov->iov_base + iov_base;
+               filemap_set_next_iovec(&cur_iov, &iov_offset, written);
+               buf = cur_iov->iov_base + iov_offset;
        }
 
        do {
-               unsigned long index;
-               unsigned long offset;
-               unsigned long maxlen;
-               size_t copied;
+               pgoff_t index;          /* Pagecache index for current page */
+               unsigned long offset;   /* Offset into pagecache page */
+               unsigned long maxlen;   /* Bytes remaining in current iovec */
+               size_t bytes;           /* Bytes to write to page */
+               size_t copied;          /* Bytes copied from user */
 
-               offset = (pos & (PAGE_CACHE_SIZE -1)); /* Within page */
+               offset = (pos & (PAGE_CACHE_SIZE - 1));
                index = pos >> PAGE_CACHE_SHIFT;
                bytes = PAGE_CACHE_SIZE - offset;
                if (bytes > count)
                        bytes = count;
 
+               maxlen = cur_iov->iov_len - iov_offset;
+               if (maxlen > bytes)
+                       maxlen = bytes;
+
                /*
                 * Bring in the user page that we will copy from _first_.
                 * Otherwise there's a nasty deadlock on copying from the
                 * same page as we're writing to, without it being marked
                 * up-to-date.
                 */
-               maxlen = cur_iov->iov_len - iov_base;
-               if (maxlen > bytes)
-                       maxlen = bytes;
                fault_in_pages_readable(buf, maxlen);
 
                page = __grab_cache_page(mapping,index,&cached_page,&lru_pvec);
@@ -1913,7 +1914,7 @@ generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov,
                                                        buf, bytes);
                else
                        copied = filemap_copy_from_user_iovec(page, offset,
-                                               cur_iov, iov_base, bytes);
+                                               cur_iov, iov_offset, bytes);
                flush_dcache_page(page);
                status = a_ops->commit_write(file, page, offset, offset+bytes);
                if (status == AOP_TRUNCATED_PAGE) {
@@ -1931,12 +1932,12 @@ generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov,
                                buf += status;
                                if (unlikely(nr_segs > 1)) {
                                        filemap_set_next_iovec(&cur_iov,
-                                                       &iov_base, status);
+                                                       &iov_offset, status);
                                        if (count)
                                                buf = cur_iov->iov_base +
-                                                       iov_base;
+                                                       iov_offset;
                                } else {
-                                       iov_base += status;
+                                       iov_offset += status;
                                }
                        }
                }