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Subject[Suspend2][ 29/32] [Suspend2] Read or write a chunk of the header.
Date
Submit a buffer with data to write, or a buffer to be filled. In contrast
to the functions for the main portion of the image, the buffer is normally
less than a full page.

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

kernel/power/suspend_block_io.c | 67 +++++++++++++++++++++++++++++++++++++++
1 files changed, 67 insertions(+), 0 deletions(-)
diff --git a/kernel/power/suspend_block_io.c b/kernel/power/suspend_block_io.c
index f881fc7..e822b19 100644
--- a/kernel/power/suspend_block_io.c
+++ b/kernel/power/suspend_block_io.c
@@ -961,3 +961,70 @@ static int suspend_write_chunk(struct pa
return suspend_rw_page(WRITE, buffer_page, -1, 0, 0);
}

+static int suspend_rw_header_chunk(int rw, struct suspend_module_ops *owner,
+ char *buffer, int buffer_size)
+{
+ int bytes_left = buffer_size;
+
+ if (owner) {
+ owner->header_used += buffer_size;
+ if (owner->header_used > owner->header_requested) {
+ printk(KERN_EMERG "Suspend2 module %s is using more"
+ "header space (%lu) than it requested (%lu).\n",
+ owner->name,
+ owner->header_used,
+ owner->header_requested);
+ BUG();
+ }
+ }
+
+ /* Read a chunk of the header */
+ while (bytes_left) {
+ char *source_start = buffer + buffer_size - bytes_left;
+ char *dest_start = suspend_writer_buffer + suspend_writer_buffer_posn;
+ int capacity = PAGE_SIZE - suspend_writer_buffer_posn;
+ char *to = rw ? dest_start : source_start;
+ char *from = rw ? source_start : dest_start;
+
+ if (bytes_left <= capacity) {
+ if (test_debug_state(SUSPEND_HEADER))
+ printk("Copy %d bytes %d-%d from %p to %p.\n",
+ bytes_left,
+ suspend_header_bytes_used,
+ suspend_header_bytes_used + bytes_left,
+ from, to);
+ memcpy(to, from, bytes_left);
+ suspend_writer_buffer_posn += bytes_left;
+ suspend_header_bytes_used += bytes_left;
+ return rw ? 0 : buffer_size;
+ }
+
+ /* Next to read the next page */
+ if (test_debug_state(SUSPEND_HEADER))
+ printk("Copy %d bytes (%d-%d) from %p to %p.\n",
+ capacity,
+ suspend_header_bytes_used,
+ suspend_header_bytes_used + capacity,
+ from, to);
+ memcpy(to, from, capacity);
+ bytes_left -= capacity;
+ suspend_header_bytes_used += capacity;
+
+ if (rw == READ && test_suspend_state(SUSPEND_TRY_RESUME_RD))
+ sys_read(suspend_read_fd,
+ suspend_writer_buffer, BLOCK_SIZE);
+ else {
+ if (suspend_rw_page(rw,
+ virt_to_page(suspend_writer_buffer),
+ -1, !rw,
+ test_debug_state(SUSPEND_HEADER)))
+ return -EIO;
+ }
+
+ suspend_writer_buffer_posn = 0;
+ suspend_cond_pause(0, NULL);
+ }
+
+ return rw ? 0 : buffer_size;
+}
+
--
Nigel Cunningham nigel at suspend2 dot net
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