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>

1 files changed, 18 insertions, 17 deletions

diff --git a/mm/filemap.c b/mm/filemap.c
index 4bf7d1ab6c2a..f74d05201862 100644
--- 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;
                                 }
                         }
                 }