[PATCH 08/16] nvme-auth: don't keep long lived 4k dhchap buffer

[Sagi Grimberg]

dhchap structure is per-queue, it is wasteful to keep it for the entire
lifetime of the queue. Allocate it dynamically and get rid of it after
authentication. We don't need kzalloc because all accessors are clearing
it before writing to it.

Signed-off-by: Sagi Grimberg <sagi at grimberg.me>
---
 drivers/nvme/host/auth.c | 27 +++++++++++++--------------
 1 file changed, 13 insertions(+), 14 deletions(-)

diff --git a/drivers/nvme/host/auth.c b/drivers/nvme/host/auth.c
index 07d497f49e4b..201f25267685 100644
--- a/drivers/nvme/host/auth.c
+++ b/drivers/nvme/host/auth.c
@@ -674,6 +674,8 @@ static void nvme_auth_reset_dhchap(struct nvme_dhchap_queue_context *chap)
 	chap->transaction = 0;
 	memset(chap->c1, 0, sizeof(chap->c1));
 	memset(chap->c2, 0, sizeof(chap->c2));
+	kfree(chap->buf);
+	chap->buf = NULL;
 }
 
 static void nvme_auth_free_dhchap(struct nvme_dhchap_queue_context *chap)
@@ -683,7 +685,6 @@ static void nvme_auth_free_dhchap(struct nvme_dhchap_queue_context *chap)
 		crypto_free_shash(chap->shash_tfm);
 	if (chap->dh_tfm)
 		crypto_free_kpp(chap->dh_tfm);
-	kfree(chap->buf);
 	kfree(chap);
 }
 
@@ -695,6 +696,17 @@ static void __nvme_auth_work(struct work_struct *work)
 	size_t tl;
 	int ret = 0;
 
+	/*
+	 * Allocate a large enough buffer for the entire negotiation:
+	 * 4k should be enough to ffdhe8192.
+	 */
+	chap->buf_size = 4096;
+	chap->buf = kmalloc(chap->buf_size, GFP_KERNEL);
+	if (!chap->buf) {
+		chap->error = -ENOMEM;
+		return;
+	}
+
 	chap->transaction = ctrl->transaction++;
 
 	/* DH-HMAC-CHAP Step 1: send negotiate */
@@ -876,19 +888,6 @@ int nvme_auth_negotiate(struct nvme_ctrl *ctrl, int qid)
 	}
 	chap->qid = qid;
 	chap->ctrl = ctrl;
-
-	/*
-	 * Allocate a large enough buffer for the entire negotiation:
-	 * 4k should be enough to ffdhe8192.
-	 */
-	chap->buf_size = 4096;
-	chap->buf = kzalloc(chap->buf_size, GFP_KERNEL);
-	if (!chap->buf) {
-		mutex_unlock(&ctrl->dhchap_auth_mutex);
-		kfree(chap);
-		return -ENOMEM;
-	}
-
 	INIT_WORK(&chap->auth_work, __nvme_auth_work);
 	list_add(&chap->entry, &ctrl->dhchap_auth_list);
 	mutex_unlock(&ctrl->dhchap_auth_mutex);
-- 
2.34.1