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>

1 files changed, 37 insertions, 30 deletions

diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index f45228eac3e6..0503380704de 100644
--- 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++;