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Commit 6659b435 authored by Daniel Rosenberg's avatar Daniel Rosenberg
Browse files

Revert "ANDROID: Squashfs: optimize reading uncompressed data" 



This reverts commit c9065640.

Signed-off-by: default avatarDaniel Rosenberg <drosen@google.com>
Change-Id: If572940d150622ed20082a64bc7611add95a87f4
parent 91891413

fs/squashfs/block.c

+0 −25
Original line number Diff line number Diff line
@@ -207,22 +207,6 @@ static void squashfs_bio_end_io(struct bio *bio) 
	kfree(bio_req);

}



static int bh_is_optional(struct squashfs_read_request *req, int idx)

{

	int start_idx, end_idx;

	struct squashfs_sb_info *msblk = req->sb->s_fs_info;



	start_idx = (idx * msblk->devblksize - req->offset) >> PAGE_SHIFT;

	end_idx = ((idx + 1) * msblk->devblksize - req->offset + 1) >> PAGE_SHIFT;

	if (start_idx >= req->output->pages)

		return 1;

	if (start_idx < 0)

		start_idx = end_idx;

	if (end_idx >= req->output->pages)

		end_idx = start_idx;

	return !req->output->page[start_idx] && !req->output->page[end_idx];

}



static int actor_getblks(struct squashfs_read_request *req, u64 block)

{

	int i;
@@ -232,15 +216,6 @@ static int actor_getblks(struct squashfs_read_request *req, u64 block) 
		return -ENOMEM;



	for (i = 0; i < req->nr_buffers; ++i) {

		/*

		 * When dealing with an uncompressed block, the actor may

		 * contains NULL pages. There's no need to read the buffers

		 * associated with these pages.

		 */

		if (!req->compressed && bh_is_optional(req, i)) {

			req->bh[i] = NULL;

			continue;

		}

		req->bh[i] = sb_getblk(req->sb, block + i);

		if (!req->bh[i]) {

			while (--i) {

fs/squashfs/file_direct.c

+7 −30
Original line number Diff line number Diff line
@@ -111,38 +111,15 @@ int squashfs_readpages_block(struct page *target_page, 
	struct squashfs_page_actor *actor;

	struct inode *inode = mapping->host;

	struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info;

	int start_index, end_index, file_end, actor_pages, res;

	int file_end = (i_size_read(inode) - 1) >> PAGE_SHIFT;

	int mask = (1 << (msblk->block_log - PAGE_SHIFT)) - 1;

	int start_index = page_index & ~mask;

	int end_index = start_index | mask;

	int actor_pages, res;



	/*

	 * If readpage() is called on an uncompressed datablock, we can just

	 * read the pages instead of fetching the whole block.

	 * This greatly improves the performance when a process keep doing

	 * random reads because we only fetch the necessary data.

	 * The readahead algorithm will take care of doing speculative reads

	 * if necessary.

	 * We can't read more than 1 block even if readahead provides use more

	 * pages because we don't know yet if the next block is compressed or

	 * not.

	 */

	if (bsize && !SQUASHFS_COMPRESSED_BLOCK(bsize)) {

		u64 block_end = block + msblk->block_size;



		block += (page_index & mask) * PAGE_SIZE;

		actor_pages = (block_end - block) / PAGE_SIZE;

		if (*nr_pages < actor_pages)

			actor_pages = *nr_pages;

		start_index = page_index;

		bsize = min_t(int, bsize, (PAGE_SIZE * actor_pages)

					  | SQUASHFS_COMPRESSED_BIT_BLOCK);

	} else {

		file_end = (i_size_read(inode) - 1) >> PAGE_SHIFT;

		start_index = page_index & ~mask;

		end_index = start_index | mask;

	if (end_index > file_end)

		end_index = file_end;

	actor_pages = end_index - start_index + 1;

	}



	actor = actor_from_page_cache(actor_pages, target_page,

				      readahead_pages, nr_pages, start_index,