ANDROID: Squashfs: refactor page_actor
This patch essentially does 3 things:
1/ Always use an array of page to store the data instead of a mix of
buffers and pages.
2/ It is now possible to have 'holes' in a page actor, i.e. NULL
pages in the array.
When reading a block (default 128K), squashfs tries to grab all
the pages covering this block. If a single page is up-to-date or
locked, it falls back to using an intermediate buffer to do the
read and then copy the pages in the actor. Allowing holes in the
page actor remove the need for this intermediate buffer.
3/ Refactor the wrappers to share code that deals with page actors.
Change-Id: I975801b32966b7ea930aebbb32d1b77233d2d2ce
Signed-off-by: Adrien Schildknecht <adriens@google.com>
diff --git a/fs/squashfs/xz_wrapper.c b/fs/squashfs/xz_wrapper.c
index 6bfaef7..2f7be1f 100644
--- a/fs/squashfs/xz_wrapper.c
+++ b/fs/squashfs/xz_wrapper.c
@@ -55,7 +55,7 @@
struct comp_opts *opts;
int err = 0, n;
- opts = kmalloc(sizeof(*opts), GFP_KERNEL);
+ opts = kmalloc(sizeof(*opts), GFP_ATOMIC);
if (opts == NULL) {
err = -ENOMEM;
goto out2;
@@ -136,6 +136,7 @@
enum xz_ret xz_err;
int avail, total = 0, k = 0;
struct squashfs_xz *stream = strm;
+ void *buf = NULL;
xz_dec_reset(stream->state);
stream->buf.in_pos = 0;
@@ -156,12 +157,20 @@
if (stream->buf.out_pos == stream->buf.out_size) {
stream->buf.out = squashfs_next_page(output);
- if (stream->buf.out != NULL) {
+ if (!IS_ERR(stream->buf.out)) {
stream->buf.out_pos = 0;
total += PAGE_SIZE;
}
}
+ if (!stream->buf.out) {
+ if (!buf) {
+ buf = kmalloc(PAGE_SIZE, GFP_ATOMIC);
+ if (!buf)
+ goto out;
+ }
+ stream->buf.out = buf;
+ }
xz_err = xz_dec_run(stream->state, &stream->buf);
if (stream->buf.in_pos == stream->buf.in_size && k < b)
@@ -173,11 +182,13 @@
if (xz_err != XZ_STREAM_END || k < b)
goto out;
+ kfree(buf);
return total + stream->buf.out_pos;
out:
for (; k < b; k++)
put_bh(bh[k]);
+ kfree(buf);
return -EIO;
}