[PATCH][next] mm/zswap: fix a couple of memory leaks and rework kzalloc failure check

[Colin King]

From: Colin Ian King <colin.k...@canonical.com>

kzalloc failures return NULL on out of memory errors, so replace the
IS_ERR_OR_NULL check with the usual null pointer check.  Fix two memory
leaks with on acomp and acomp_ctx by ensuring these objects are free'd
on the error return path.

Addresses-Coverity: ("Resource leak")
Fixes: d4f86abd6e35 ("mm/zswap: move to use crypto_acomp API for hardware 
acceleration")
Signed-off-by: Colin Ian King <colin.k...@canonical.com>
---
 mm/zswap.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/mm/zswap.c b/mm/zswap.c
index 0d914ba6b4a0..14839cbac7ff 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -433,23 +433,23 @@ static int zswap_cpu_comp_prepare(unsigned int cpu, 
struct hlist_node *node)
                return 0;
 
        acomp_ctx = kzalloc(sizeof(*acomp_ctx), GFP_KERNEL);
-       if (IS_ERR_OR_NULL(acomp_ctx)) {
+       if (!acomp_ctx) {
                pr_err("Could not initialize acomp_ctx\n");
                return -ENOMEM;
        }
        acomp = crypto_alloc_acomp(pool->tfm_name, 0, 0);
-       if (IS_ERR_OR_NULL(acomp)) {
+       if (!acomp) {
                pr_err("could not alloc crypto acomp %s : %ld\n",
                                pool->tfm_name, PTR_ERR(acomp));
-               return -ENOMEM;
+               goto free_acomp_ctx;
        }
        acomp_ctx->acomp = acomp;
 
        req = acomp_request_alloc(acomp_ctx->acomp);
-       if (IS_ERR_OR_NULL(req)) {
+       if (!req) {
                pr_err("could not alloc crypto acomp %s : %ld\n",
                       pool->tfm_name, PTR_ERR(acomp));
-               return -ENOMEM;
+               goto free_acomp;
        }
        acomp_ctx->req = req;
 
@@ -462,6 +462,12 @@ static int zswap_cpu_comp_prepare(unsigned int cpu, struct 
hlist_node *node)
        *per_cpu_ptr(pool->acomp_ctx, cpu) = acomp_ctx;
 
        return 0;
+
+free_acomp:
+       kfree(acomp);
+free_acomp_ctx:
+       kfree(acomp_ctx);
+       return -ENOMEM;
 }
 
 static int zswap_cpu_comp_dead(unsigned int cpu, struct hlist_node *node)
-- 
2.27.0