1 files changed, 97 insertions, 0 deletions

diff --git a/fs/squashfs/decompressor_multi_percpu.c b/fs/squashfs/decompressor_multi_percpu.c
new file mode 100644
index 000000000000..23a9c28ad8ea
--- /dev/null
+++ b/fs/squashfs/decompressor_multi_percpu.c
@@ -0,0 +1,97 @@
+/*
+ * Copyright (c) 2013
+ * Phillip Lougher <phillip@squashfs.org.uk>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2. See
+ * the COPYING file in the top-level directory.
+ */
+
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/percpu.h>
+#include <linux/buffer_head.h>
+
+#include "squashfs_fs.h"
+#include "squashfs_fs_sb.h"
+#include "decompressor.h"
+#include "squashfs.h"
+
+/*
+ * This file implements multi-threaded decompression using percpu
+ * variables, one thread per cpu core.
+ */
+
+struct squashfs_stream {
+        void            *stream;
+};
+
+void *squashfs_decompressor_create(struct squashfs_sb_info *msblk,
+                                                void *comp_opts)
+{
+        struct squashfs_stream *stream;
+        struct squashfs_stream __percpu *percpu;
+        int err, cpu;
+
+        percpu = alloc_percpu(struct squashfs_stream);
+        if (percpu == NULL)
+                return ERR_PTR(-ENOMEM);
+
+        for_each_possible_cpu(cpu) {
+                stream = per_cpu_ptr(percpu, cpu);
+                stream->stream = msblk->decompressor->init(msblk, comp_opts);
+                if (IS_ERR(stream->stream)) {
+                        err = PTR_ERR(stream->stream);
+                        goto out;
+                }
+        }
+
+        kfree(comp_opts);
+        return (__force void *) percpu;
+
+out:
+        for_each_possible_cpu(cpu) {
+                stream = per_cpu_ptr(percpu, cpu);
+                if (!IS_ERR_OR_NULL(stream->stream))
+                        msblk->decompressor->free(stream->stream);
+        }
+        free_percpu(percpu);
+        return ERR_PTR(err);
+}
+
+void squashfs_decompressor_destroy(struct squashfs_sb_info *msblk)
+{
+        struct squashfs_stream __percpu *percpu =
+                        (struct squashfs_stream __percpu *) msblk->stream;
+        struct squashfs_stream *stream;
+        int cpu;
+
+        if (msblk->stream) {
+                for_each_possible_cpu(cpu) {
+                        stream = per_cpu_ptr(percpu, cpu);
+                        msblk->decompressor->free(stream->stream);
+                }
+                free_percpu(percpu);
+        }
+}
+
+int squashfs_decompress(struct squashfs_sb_info *msblk, struct buffer_head **bh,
+        int b, int offset, int length, struct squashfs_page_actor *output)
+{
+        struct squashfs_stream __percpu *percpu =
+                        (struct squashfs_stream __percpu *) msblk->stream;
+        struct squashfs_stream *stream = get_cpu_ptr(percpu);
+        int res = msblk->decompressor->decompress(msblk, stream->stream, bh, b,
+                offset, length, output);
+        put_cpu_ptr(stream);
+
+        if (res < 0)
+                ERROR("%s decompression failed, data probably corrupt\n",
+                        msblk->decompressor->name);
+
+        return res;
+}
+
+int squashfs_max_decompressors(void)
+{
+        return num_possible_cpus();
+}