lkml.org 
[lkml]   [2006]   [Jun]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[Suspend2][ 05/13] [Suspend2] Compression write routines.
Date
Add routines used in compressing pages and passing them to the next module.

Signed-off-by: Nigel Cunningham <nigel@suspend2.net>

kernel/power/compression.c | 87 ++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 87 insertions(+), 0 deletions(-)

diff --git a/kernel/power/compression.c b/kernel/power/compression.c
index 44d46be..db3bca3 100644
--- a/kernel/power/compression.c
+++ b/kernel/power/compression.c
@@ -188,3 +188,90 @@ static int suspend_compress_rw_init(int
return 0;
}

+/*
+ * suspend_compress_write()
+ * @u8*: Output buffer to be written.
+ * @unsigned int: Length of buffer.
+ *
+ * Helper function for write_chunk. Write the compressed data.
+ * Return: Int. Result to be passed back to caller.
+ */
+static int suspend_compress_write (u8 *buffer, unsigned int len)
+{
+ int ret;
+
+ bytes_out += len;
+
+ while (len + bufofs > PAGE_SIZE) {
+ unsigned int chunk = PAGE_SIZE - bufofs;
+ memcpy (local_buffer + bufofs, buffer, chunk);
+ buffer += chunk;
+ len -= chunk;
+ bufofs = 0;
+ if ((ret = next_driver->write_chunk(virt_to_page(local_buffer))) < 0)
+ return ret;
+ }
+ memcpy (local_buffer + bufofs, buffer, len);
+ bufofs += len;
+ return 0;
+}
+
+/*
+ * suspend_compress_write_chunk()
+ *
+ * Compress a page of data, buffering output and passing on filled
+ * pages to the next module in the pipeline.
+ *
+ * Buffer_page: Pointer to a buffer of size PAGE_SIZE, containing
+ * data to be compressed.
+ *
+ * Returns: 0 on success. Otherwise the error is that returned by later
+ * modules, -ECHILD if we have a broken pipeline or -EIO if
+ * zlib errs.
+ */
+static int suspend_compress_write_chunk(struct page *buffer_page)
+{
+ int ret;
+ unsigned int len;
+ u16 len_written;
+ char *buffer_start;
+
+ if (!suspend_compressor_transform)
+ return next_driver->write_chunk(buffer_page);
+
+ buffer_start = kmap(buffer_page);
+
+ bytes_in += PAGE_SIZE;
+
+ len = PAGE_SIZE;
+
+ ret = crypto_comp_compress(suspend_compressor_transform,
+ buffer_start, PAGE_SIZE,
+ page_buffer, &len);
+
+ if (ret) {
+ printk("Compression failed.\n");
+ goto failure;
+ }
+
+ len_written = (u16) len;
+
+ if ((ret = suspend_compress_write((u8 *)&len_written, 2)) >= 0) {
+ if ((ret = suspend_compress_write((u8 *) &position, sizeof(position))))
+ return -EIO;
+ if (len < PAGE_SIZE) { /* some compression */
+ position += len;
+ ret = suspend_compress_write(page_buffer, len);
+ } else {
+ ret = suspend_compress_write(buffer_start, PAGE_SIZE);
+ position += PAGE_SIZE;
+ }
+ }
+ position += 2 + sizeof(int);
+
+
+failure:
+ kunmap(buffer_page);
+ return ret;
+}
+
--
Nigel Cunningham nigel at suspend2 dot net
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2006-06-27 07:18    [W:0.520 / U:0.032 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site