PM: hibernate: Emit an error when image writing fails

If image writing fails, a return code is passed up to the caller, but
none of the callers log anything to the log and so the only record
of it is the return code that userspace gets.

Adjust the logging so that the image size and speed of writing is
only emitted on success and if there is an error, it's saved to the
logs.

Fixes: a06c6f5 ("PM: hibernate: Move to crypto APIs for LZO compression")
Reported-by: Askar Safin <safinaskar@gmail.com>
Closes: https://lore.kernel.org/linux-pm/20251105180506.137448-1-safinaskar@gmail.com/
Signed-off-by: Mario Limonciello (AMD) <superm1@kernel.org>
Tested-by: Askar Safin <safinaskar@gmail.com>
Cc: 6.9+ <stable@vger.kernel.org> # 6.9+
[ rjw: Added missing braces after "else", changelog edits ]
Link: https://patch.msgid.link/20251106045158.3198061-2-superm1@kernel.org
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Author: superm1

kernel/power/swap.c

@@ -877,11 +877,14 @@ static int save_compressed_image(struct swap_map_handle *handle,
 	stop = ktime_get();
 	if (!ret)
 		ret = err2;
-	if (!ret)
+	if (!ret) {
+		swsusp_show_speed(start, stop, nr_to_write, "Wrote");
+		pr_info("Image size after compression: %d kbytes\n",
+			(atomic_read(&compressed_size) / 1024));
 		pr_info("Image saving done\n");
-	swsusp_show_speed(start, stop, nr_to_write, "Wrote");
-	pr_info("Image size after compression: %d kbytes\n",
-		(atomic_read(&compressed_size) / 1024));
+	} else {
+		pr_err("Image saving failed: %d\n", ret);
+	}
 
 out_clean:
 	hib_finish_batch(&hb);