Squashfs: Generalise paging handling in the decompressors
Further generalise the decompressors by adding a page handler
abstraction. This adds helpers to allow the decompressors
to access and process the output buffers in an implementation
independant manner.
This allows different types of output buffer to be passed
to the decompressors, with the implementation specific
aspects handled at decompression time, but without the
knowledge being held in the decompressor wrapper code.
This will allow the decompressors to handle Squashfs
cache buffers, and page cache pages.
This patch adds the abstraction and an implementation for
the caches.
Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
Reviewed-by: Minchan Kim <minchan@kernel.org>
diff --git a/fs/squashfs/decompressor.c b/fs/squashfs/decompressor.c
index 234291f..ac22fe7 100644
--- a/fs/squashfs/decompressor.c
+++ b/fs/squashfs/decompressor.c
@@ -30,6 +30,7 @@
#include "squashfs_fs_sb.h"
#include "decompressor.h"
#include "squashfs.h"
+#include "page_actor.h"
/*
* This file (and decompressor.h) implements a decompressor framework for
@@ -87,6 +88,7 @@
{
struct squashfs_sb_info *msblk = sb->s_fs_info;
void *buffer = NULL, *comp_opts;
+ struct squashfs_page_actor *actor = NULL;
int length = 0;
/*
@@ -99,9 +101,14 @@
goto out;
}
- length = squashfs_read_data(sb, &buffer,
- sizeof(struct squashfs_super_block), 0, NULL,
- PAGE_CACHE_SIZE, 1);
+ actor = squashfs_page_actor_init(&buffer, 1, 0);
+ if (actor == NULL) {
+ comp_opts = ERR_PTR(-ENOMEM);
+ goto out;
+ }
+
+ length = squashfs_read_data(sb,
+ sizeof(struct squashfs_super_block), 0, NULL, actor);
if (length < 0) {
comp_opts = ERR_PTR(length);
@@ -112,6 +119,7 @@
comp_opts = squashfs_comp_opts(msblk, buffer, length);
out:
+ kfree(actor);
kfree(buffer);
return comp_opts;
}
