Merge tag 'core-rcu-2020-06-01' of git://git.kernel.org/pub/scm/linux/kernel/git...

[linux-2.6-microblaze.git] / fs / pstore / ftrace.c

diff --git a/fs/pstore/ftrace.c b/fs/pstore/ftrace.c
index bfbfc26..5c04507 100644 (file)
--- a/fs/pstore/ftrace.c
+++ b/fs/pstore/ftrace.c
@@ -16,6 +16,7 @@
 #include <linux/debugfs.h>
 #include <linux/err.h>
 #include <linux/cache.h>
+#include <linux/slab.h>
 #include <asm/barrier.h>
 #include "internal.h"
 
@@ -132,3 +133,56 @@ void pstore_unregister_ftrace(void)
 
        debugfs_remove_recursive(pstore_ftrace_dir);
 }
+
+ssize_t pstore_ftrace_combine_log(char **dest_log, size_t *dest_log_size,
+                                 const char *src_log, size_t src_log_size)
+{
+       size_t dest_size, src_size, total, dest_off, src_off;
+       size_t dest_idx = 0, src_idx = 0, merged_idx = 0;
+       void *merged_buf;
+       struct pstore_ftrace_record *drec, *srec, *mrec;
+       size_t record_size = sizeof(struct pstore_ftrace_record);
+
+       dest_off = *dest_log_size % record_size;
+       dest_size = *dest_log_size - dest_off;
+
+       src_off = src_log_size % record_size;
+       src_size = src_log_size - src_off;
+
+       total = dest_size + src_size;
+       merged_buf = kmalloc(total, GFP_KERNEL);
+       if (!merged_buf)
+               return -ENOMEM;
+
+       drec = (struct pstore_ftrace_record *)(*dest_log + dest_off);
+       srec = (struct pstore_ftrace_record *)(src_log + src_off);
+       mrec = (struct pstore_ftrace_record *)(merged_buf);
+
+       while (dest_size > 0 && src_size > 0) {
+               if (pstore_ftrace_read_timestamp(&drec[dest_idx]) <
+                   pstore_ftrace_read_timestamp(&srec[src_idx])) {
+                       mrec[merged_idx++] = drec[dest_idx++];
+                       dest_size -= record_size;
+               } else {
+                       mrec[merged_idx++] = srec[src_idx++];
+                       src_size -= record_size;
+               }
+       }
+
+       while (dest_size > 0) {
+               mrec[merged_idx++] = drec[dest_idx++];
+               dest_size -= record_size;
+       }
+
+       while (src_size > 0) {
+               mrec[merged_idx++] = srec[src_idx++];
+               src_size -= record_size;
+       }
+
+       kfree(*dest_log);
+       *dest_log = merged_buf;
+       *dest_log_size = total;
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(pstore_ftrace_combine_log);