1 files changed, 33 insertions, 15 deletions

diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 578f178a695f..b821054ca3ed 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -274,36 +274,56 @@ static int pstore_decompress(void *in, void *out,
 
 static void allocate_buf_for_compression(void)
 {
+        struct crypto_comp *ctx;
+        int size;
+        char *buf;
+
+        /* Skip if not built-in or compression backend not selected yet. */
         if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS) || !zbackend)
                 return;
 
+        /* Skip if no pstore backend yet or compression init already done. */
+        if (!psinfo || tfm)
+                return;
+
         if (!crypto_has_comp(zbackend->name, 0, 0)) {
-                pr_err("No %s compression\n", zbackend->name);
+                pr_err("Unknown compression: %s\n", zbackend->name);
                 return;
         }
 
-        big_oops_buf_sz = zbackend->zbufsize(psinfo->bufsize);
-        if (big_oops_buf_sz <= 0)
+        size = zbackend->zbufsize(psinfo->bufsize);
+        if (size <= 0) {
+                pr_err("Invalid compression size for %s: %d\n",
+                       zbackend->name, size);
                 return;
+        }
 
-        big_oops_buf = kmalloc(big_oops_buf_sz, GFP_KERNEL);
-        if (!big_oops_buf) {
-                pr_err("allocate compression buffer error!\n");
+        buf = kmalloc(size, GFP_KERNEL);
+        if (!buf) {
+                pr_err("Failed %d byte compression buffer allocation for: %s\n",
+                       size, zbackend->name);
                 return;
         }
 
-        tfm = crypto_alloc_comp(zbackend->name, 0, 0);
-        if (IS_ERR_OR_NULL(tfm)) {
-                kfree(big_oops_buf);
-                big_oops_buf = NULL;
-                pr_err("crypto_alloc_comp() failed!\n");
+        ctx = crypto_alloc_comp(zbackend->name, 0, 0);
+        if (IS_ERR_OR_NULL(ctx)) {
+                kfree(buf);
+                pr_err("crypto_alloc_comp('%s') failed: %ld\n", zbackend->name,
+                       PTR_ERR(ctx));
                 return;
         }
+
+        /* A non-NULL big_oops_buf indicates compression is available. */
+        tfm = ctx;
+        big_oops_buf_sz = size;
+        big_oops_buf = buf;
+
+        pr_info("Using compression: %s\n", zbackend->name);
 }
 
 static void free_buf_for_compression(void)
 {
-        if (IS_ENABLED(CONFIG_PSTORE_COMPRESS) && !IS_ERR_OR_NULL(tfm))
+        if (IS_ENABLED(CONFIG_PSTORE_COMPRESS) && tfm)
                 crypto_free_comp(tfm);
         kfree(big_oops_buf);
         big_oops_buf = NULL;
@@ -774,7 +794,6 @@ void __init pstore_choose_compression(void)
         for (step = zbackends; step->name; step++) {
                 if (!strcmp(compress, step->name)) {
                         zbackend = step;
-                        pr_info("using %s compression\n", zbackend->name);
                         return;
                 }
         }
@@ -791,8 +810,7 @@ static int __init pstore_init(void)
          * initialize compression because crypto was not ready. If so,
          * initialize compression now.
          */
-        if (psinfo && !tfm)
-                allocate_buf_for_compression();
+        allocate_buf_for_compression();
 
         ret = pstore_init_fs();
         if (ret)