[RFC 1/2] squashfs parallel decompression, early wait_on_buffer

["J. R. Okajima" <hooanon05@yahoo.co.jp>]

Preparing parallel decompression.
In squashfs_read_data(), move wait_on_buffer() forer which is common
part of the 'if (compressed) - else' blocks.

Signed-off-by: J. R. Okajima <hooanon05@yahoo.co.jp>
---
 fs/squashfs/block.c |   17 +++++++----------
 1 files changed, 7 insertions(+), 10 deletions(-)

diff --git a/fs/squashfs/block.c b/fs/squashfs/block.c
index 2a79603..1017b94 100644
--- a/fs/squashfs/block.c
+++ b/fs/squashfs/block.c
@@ -151,6 +151,12 @@ int squashfs_read_data(struct super_block *sb, void **buffer, u64 index,
 		}
 		ll_rw_block(READ, b - 1, bh + 1);
 	}
+	for (k = 0; k < b; k++) {
+		wait_on_buffer(bh[k]);
+		/* possible? */
+		WARN_ON(!buffer_uptodate(bh[k]));
+	}
+	k = 0;
 
 	if (compressed) {
 		int zlib_err = 0, zlib_init = 0;
@@ -169,9 +175,6 @@ int squashfs_read_data(struct super_block *sb, void **buffer, u64 index,
 			if (msblk->stream.avail_in == 0 && k < b) {
 				avail = min(bytes, msblk->devblksize - offset);
 				bytes -= avail;
-				wait_on_buffer(bh[k]);
-				if (!buffer_uptodate(bh[k]))
-					goto release_mutex;
 
 				if (avail == 0) {
 					offset = 0;
@@ -223,13 +226,7 @@ int squashfs_read_data(struct super_block *sb, void **buffer, u64 index,
 		/*
 		 * Block is uncompressed.
 		 */
-		int i, in, pg_offset = 0;
-
-		for (i = 0; i < b; i++) {
-			wait_on_buffer(bh[i]);
-			if (!buffer_uptodate(bh[i]))
-				goto block_release;
-		}
+		int in, pg_offset = 0;
 
 		for (bytes = length; k < b; k++) {
 			in = min(bytes, msblk->devblksize - offset);
-- 
1.6.6.1