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authorPhillip Lougher <phillip@squashfs.org.uk>2013-11-18 02:59:12 +0000
committerPhillip Lougher <phillip@squashfs.org.uk>2013-11-20 03:59:01 +0000
commit846b730e99518a1c9945afcb2afbe4d08a02ed80 (patch)
treec70eb16cbec15e5bfa1db80c5f18e062673331a9 /fs/squashfs/block.c
parentd208383d640727b70cd6689bc17e67e9b5ebf4ff (diff)
downloadlinux-846b730e99518a1c9945afcb2afbe4d08a02ed80.tar.bz2
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>
Diffstat (limited to 'fs/squashfs/block.c')
-rw-r--r--fs/squashfs/block.c27
1 files changed, 15 insertions, 12 deletions
diff --git a/fs/squashfs/block.c b/fs/squashfs/block.c
index 4dd402597f22..0cea9b9236d0 100644
--- a/fs/squashfs/block.c
+++ b/fs/squashfs/block.c
@@ -36,6 +36,7 @@
#include "squashfs_fs_sb.h"
#include "squashfs.h"
#include "decompressor.h"
+#include "page_actor.h"
/*
* Read the metadata block length, this is stored in the first two
@@ -86,16 +87,16 @@ static struct buffer_head *get_block_length(struct super_block *sb,
* generated a larger block - this does occasionally happen with compression
* algorithms).
*/
-int squashfs_read_data(struct super_block *sb, void **buffer, u64 index,
- int length, u64 *next_index, int srclength, int pages)
+int squashfs_read_data(struct super_block *sb, u64 index, int length,
+ u64 *next_index, struct squashfs_page_actor *output)
{
struct squashfs_sb_info *msblk = sb->s_fs_info;
struct buffer_head **bh;
int offset = index & ((1 << msblk->devblksize_log2) - 1);
u64 cur_index = index >> msblk->devblksize_log2;
- int bytes, compressed, b = 0, k = 0, page = 0, avail, i;
+ int bytes, compressed, b = 0, k = 0, avail, i;
- bh = kcalloc(((srclength + msblk->devblksize - 1)
+ bh = kcalloc(((output->length + msblk->devblksize - 1)
>> msblk->devblksize_log2) + 1, sizeof(*bh), GFP_KERNEL);
if (bh == NULL)
return -ENOMEM;
@@ -111,9 +112,9 @@ int squashfs_read_data(struct super_block *sb, void **buffer, u64 index,
*next_index = index + length;
TRACE("Block @ 0x%llx, %scompressed size %d, src size %d\n",
- index, compressed ? "" : "un", length, srclength);
+ index, compressed ? "" : "un", length, output->length);
- if (length < 0 || length > srclength ||
+ if (length < 0 || length > output->length ||
(index + length) > msblk->bytes_used)
goto read_failure;
@@ -145,7 +146,7 @@ int squashfs_read_data(struct super_block *sb, void **buffer, u64 index,
TRACE("Block @ 0x%llx, %scompressed size %d\n", index,
compressed ? "" : "un", length);
- if (length < 0 || length > srclength ||
+ if (length < 0 || length > output->length ||
(index + length) > msblk->bytes_used)
goto block_release;
@@ -165,8 +166,8 @@ int squashfs_read_data(struct super_block *sb, void **buffer, u64 index,
}
if (compressed) {
- length = squashfs_decompress(msblk, buffer, bh, b, offset,
- length, srclength, pages);
+ length = squashfs_decompress(msblk, bh, b, offset, length,
+ output);
if (length < 0)
goto read_failure;
} else {
@@ -174,19 +175,20 @@ int squashfs_read_data(struct super_block *sb, void **buffer, u64 index,
* Block is uncompressed.
*/
int in, pg_offset = 0;
+ void *data = squashfs_first_page(output);
for (bytes = length; k < b; k++) {
in = min(bytes, msblk->devblksize - offset);
bytes -= in;
while (in) {
if (pg_offset == PAGE_CACHE_SIZE) {
- page++;
+ data = squashfs_next_page(output);
pg_offset = 0;
}
avail = min_t(int, in, PAGE_CACHE_SIZE -
pg_offset);
- memcpy(buffer[page] + pg_offset,
- bh[k]->b_data + offset, avail);
+ memcpy(data + pg_offset, bh[k]->b_data + offset,
+ avail);
in -= avail;
pg_offset += avail;
offset += avail;
@@ -194,6 +196,7 @@ int squashfs_read_data(struct super_block *sb, void **buffer, u64 index,
offset = 0;
put_bh(bh[k]);
}
+ squashfs_finish_page(output);
}
kfree(bh);