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/cache.c b/fs/squashfs/cache.c
index af0b738..1cb70a0 100644
--- a/fs/squashfs/cache.c
+++ b/fs/squashfs/cache.c
@@ -56,6 +56,7 @@
#include "squashfs_fs.h"
#include "squashfs_fs_sb.h"
#include "squashfs.h"
+#include "page_actor.h"
/*
* Look-up block in cache, and increment usage count. If not in cache, read
@@ -119,9 +120,8 @@
entry->error = 0;
spin_unlock(&cache->lock);
- entry->length = squashfs_read_data(sb, entry->data,
- block, length, &entry->next_index,
- cache->block_size, cache->pages);
+ entry->length = squashfs_read_data(sb, block, length,
+ &entry->next_index, entry->actor);
spin_lock(&cache->lock);
@@ -220,6 +220,7 @@
kfree(cache->entry[i].data[j]);
kfree(cache->entry[i].data);
}
+ kfree(cache->entry[i].actor);
}
kfree(cache->entry);
@@ -280,6 +281,13 @@
goto cleanup;
}
}
+
+ entry->actor = squashfs_page_actor_init(entry->data,
+ cache->pages, 0);
+ if (entry->actor == NULL) {
+ ERROR("Failed to allocate %s cache entry\n", name);
+ goto cleanup;
+ }
}
return cache;
@@ -410,6 +418,7 @@
int pages = (length + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
int i, res;
void *table, *buffer, **data;
+ struct squashfs_page_actor *actor;
table = buffer = kmalloc(length, GFP_KERNEL);
if (table == NULL)
@@ -421,19 +430,28 @@
goto failed;
}
+ actor = squashfs_page_actor_init(data, pages, length);
+ if (actor == NULL) {
+ res = -ENOMEM;
+ goto failed2;
+ }
+
for (i = 0; i < pages; i++, buffer += PAGE_CACHE_SIZE)
data[i] = buffer;
- res = squashfs_read_data(sb, data, block, length |
- SQUASHFS_COMPRESSED_BIT_BLOCK, NULL, length, pages);
+ res = squashfs_read_data(sb, block, length |
+ SQUASHFS_COMPRESSED_BIT_BLOCK, NULL, actor);
kfree(data);
+ kfree(actor);
if (res < 0)
goto failed;
return table;
+failed2:
+ kfree(data);
failed:
kfree(table);
return ERR_PTR(res);
