pstore: Move record decompression to function

This moves the record decompression logic out to a separate function
to avoid the deep indentation.

Signed-off-by: Kees Cook <keescook@chromium.org>

diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index f45228e..0503380 100644 (file)
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -757,6 +757,37 @@ void pstore_unregister(struct pstore_info *psi)
 }
 EXPORT_SYMBOL_GPL(pstore_unregister);
 
+static void decompress_record(struct pstore_record *record)
+{
+       int unzipped_len;
+
+       /* Only PSTORE_TYPE_DMESG support compression. */
+       if (!record->compressed || record->type != PSTORE_TYPE_DMESG) {
+               pr_warn("ignored compressed record type %d\n", record->type);
+               return;
+       }
+
+       /* No compression method has created the common buffer. */
+       if (!big_oops_buf) {
+               pr_warn("no decompression buffer allocated\n");
+               return;
+       }
+
+       unzipped_len = pstore_decompress(record->buf, big_oops_buf,
+                                        record->size, big_oops_buf_sz);
+       if (unzipped_len > 0) {
+               if (record->ecc_notice_size)
+                       memcpy(big_oops_buf + unzipped_len,
+                              record->buf + record->size,
+                              record->ecc_notice_size);
+               kfree(record->buf);
+               record->buf = big_oops_buf;
+               record->size = unzipped_len;
+               record->compressed = false;
+       } else
+               pr_err("decompression failed: %d\n", unzipped_len);
+}
+
 /*
  * Read all the records from the persistent store. Create
  * files in our filesystem.  Don't warn about -EEXIST errors
@@ -768,7 +799,6 @@ void pstore_get_records(int quiet)
        struct pstore_info *psi = psinfo;
        struct pstore_record    record = { .psi = psi, };
        int                     failed = 0, rc;
-       int                     unzipped_len = -1;
 
        if (!psi)
                return;
@@ -782,41 +812,18 @@ void pstore_get_records(int quiet)
                                 &record.buf, &record.compressed,
                                 &record.ecc_notice_size,
                                 record.psi)) > 0) {
-               if (record.compressed &&
-                   record.type == PSTORE_TYPE_DMESG) {
-                       if (big_oops_buf)
-                               unzipped_len = pstore_decompress(
-                                                       record.buf,
-                                                       big_oops_buf,
-                                                       record.size,
-                                                       big_oops_buf_sz);
-
-                       if (unzipped_len > 0) {
-                               if (record.ecc_notice_size)
-                                       memcpy(big_oops_buf + unzipped_len,
-                                              record.buf + record.size,
-                                              record.ecc_notice_size);
-                               kfree(record.buf);
-                               record.buf = big_oops_buf;
-                               record.size = unzipped_len;
-                               record.compressed = false;
-                       } else {
-                               pr_err("decompression failed;returned %d\n",
-                                      unzipped_len);
-                               record.compressed = true;
-                       }
-               }
+
+               decompress_record(&record);
                rc = pstore_mkfile(record.type, psi->name, record.id,
                                   record.count, record.buf,
                                   record.compressed,
                                   record.size + record.ecc_notice_size,
                                   record.time, record.psi);
-               if (unzipped_len < 0) {
-                       /* Free buffer other than big oops */
+
+               /* Free buffer other than big oops */
+               if (record.buf != big_oops_buf)
                        kfree(record.buf);
-                       record.buf = NULL;
-               } else
-                       unzipped_len = -1;
+
                if (rc && (rc != -EEXIST || !quiet))
                        failed++;