The patch titled
do_mpage_readpage(): remove first_logical_block parameter
has been removed from the -mm tree. Its filename was
do_mpage_readpage-remove-first_logical_block-parameter.patch
This patch was dropped because it had testing failures
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: do_mpage_readpage(): remove first_logical_block parameter
From: Franck Bui-Huu <fbuihuu@xxxxxxxxx>
Mak this function more readable by getting rid of its parameter
'first_logical_block'.
This parameter was previously used to remember the original block number
in the file (ie the page index) that 'map_bh' was pointing at first.
Indeed this was needed since 'map_bh->page' was modified even if 'map_bh'
maps the whole current page (IOW when get_block() is not used). This had
the bad effect to make the state of 'map_bh' inconsistent too.
This patch changes 'map_bh->page' only when get_block() is called hence
removes the need of the 'first_logical_block' argument.
The value stored in 'logical_block_parameter' is now recalculated each
time do_mpage_readpage() but it shouldn't matter since the operation is
trivial.
While at it, this patch does a few extra cleanups such as removing a
trailing space, moving 2 declarations of local variables closer to the
place they're used.
Signed-off-by: Franck Bui-Huu <fbuihuu@xxxxxxxxx>
Cc: Nick Piggin <nickpiggin@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/mpage.c | 64 ++++++++++++++++++++++++++-------------------------
1 file changed, 33 insertions(+), 31 deletions(-)
diff -puN fs/mpage.c~do_mpage_readpage-remove-first_logical_block-parameter fs/mpage.c
--- a/fs/mpage.c~do_mpage_readpage-remove-first_logical_block-parameter
+++ a/fs/mpage.c
@@ -168,7 +168,7 @@ map_buffer_to_page(struct page *page, st
static struct bio *
do_mpage_readpage(struct bio *bio, struct page *page, unsigned nr_pages,
sector_t *last_block_in_bio, struct buffer_head *map_bh,
- unsigned long *first_logical_block, get_block_t get_block)
+ get_block_t get_block)
{
struct inode *inode = page->mapping->host;
const unsigned blkbits = inode->i_blkbits;
@@ -183,8 +183,6 @@ do_mpage_readpage(struct bio *bio, struc
struct block_device *bdev = NULL;
int length;
int fully_mapped = 1;
- unsigned nblocks;
- unsigned relative_block;
if (page_has_buffers(page))
goto confused;
@@ -199,40 +197,45 @@ do_mpage_readpage(struct bio *bio, struc
/*
* Map blocks using the result from the previous get_blocks call first.
*/
- nblocks = map_bh->b_size >> blkbits;
- if (buffer_mapped(map_bh) && block_in_file > *first_logical_block &&
- block_in_file < (*first_logical_block + nblocks)) {
- unsigned map_offset = block_in_file - *first_logical_block;
- unsigned last = nblocks - map_offset;
-
- for (relative_block = 0; ; relative_block++) {
- if (relative_block == last) {
- clear_buffer_mapped(map_bh);
- break;
+ if (buffer_mapped(map_bh)) {
+ unsigned nblocks = map_bh->b_size >> blkbits;
+ sector_t map_block = (sector_t)map_bh->b_page->index <<
+ (PAGE_CACHE_SHIFT - blkbits);
+
+ if (block_in_file > map_block &&
+ block_in_file < map_block + nblocks) {
+ unsigned blocknr_off = block_in_file - map_block;
+ sector_t map_blocknr = map_bh->b_blocknr;
+
+ for (;; blocknr_off++) {
+ if (blocknr_off == nblocks) {
+ clear_buffer_mapped(map_bh);
+ break;
+ }
+ if (page_block == blocks_per_page)
+ break;
+ blocks[page_block] = map_blocknr + blocknr_off;
+ page_block++;
+ block_in_file++;
}
- if (page_block == blocks_per_page)
- break;
- blocks[page_block] = map_bh->b_blocknr + map_offset +
- relative_block;
- page_block++;
- block_in_file++;
+ bdev = map_bh->b_bdev;
}
- bdev = map_bh->b_bdev;
}
/*
* Then do more get_blocks calls until we are done with this page.
*/
- map_bh->b_page = page;
while (page_block < blocks_per_page) {
+ unsigned nblocks, blocknr_off = 0;
+
map_bh->b_state = 0;
map_bh->b_size = 0;
if (block_in_file < last_block) {
+ map_bh->b_page = page;
map_bh->b_size = (last_block-block_in_file) << blkbits;
if (get_block(inode, block_in_file, map_bh, 0))
goto confused;
- *first_logical_block = block_in_file;
}
if (!buffer_mapped(map_bh)) {
@@ -254,21 +257,23 @@ do_mpage_readpage(struct bio *bio, struc
map_buffer_to_page(page, map_bh, page_block);
goto confused;
}
-
+
if (first_hole != blocks_per_page)
goto confused; /* hole -> non-hole */
/* Contiguous blocks? */
if (page_block && blocks[page_block-1] != map_bh->b_blocknr-1)
goto confused;
+
nblocks = map_bh->b_size >> blkbits;
- for (relative_block = 0; ; relative_block++) {
- if (relative_block == nblocks) {
+ for (;; blocknr_off++) {
+ if (blocknr_off == nblocks) {
clear_buffer_mapped(map_bh);
break;
- } else if (page_block == blocks_per_page)
+ }
+ if (page_block == blocks_per_page)
break;
- blocks[page_block] = map_bh->b_blocknr+relative_block;
+ blocks[page_block] = map_bh->b_blocknr + blocknr_off;
page_block++;
block_in_file++;
}
@@ -378,7 +383,6 @@ mpage_readpages(struct address_space *ma
unsigned page_idx;
sector_t last_block_in_bio = 0;
struct buffer_head map_bh;
- unsigned long first_logical_block = 0;
clear_buffer_mapped(&map_bh);
for (page_idx = 0; page_idx < nr_pages; page_idx++) {
@@ -391,7 +395,6 @@ mpage_readpages(struct address_space *ma
bio = do_mpage_readpage(bio, page,
nr_pages - page_idx,
&last_block_in_bio, &map_bh,
- &first_logical_block,
get_block);
}
page_cache_release(page);
@@ -411,11 +414,10 @@ int mpage_readpage(struct page *page, ge
struct bio *bio = NULL;
sector_t last_block_in_bio = 0;
struct buffer_head map_bh;
- unsigned long first_logical_block = 0;
clear_buffer_mapped(&map_bh);
bio = do_mpage_readpage(bio, page, 1, &last_block_in_bio,
- &map_bh, &first_logical_block, get_block);
+ &map_bh, get_block);
if (bio)
mpage_bio_submit(READ, bio);
return 0;
_
Patches currently in -mm which might be from fbuihuu@xxxxxxxxx are
do_mpage_readpage-remove-useless-clear_buffer_mapped-call.patch
do_mpage_readpage-remove-first_logical_block-parameter.patch
block_write_begin-remove-useless-goto.patch
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