[PATCH V2 2/4] nvmet_auth: use common helper for buffer alloc

[Chaitanya Kulkarni]

Add a common helper to factor out buffer allocation in
nvmet_execute_auth_send() and nvmet_execute_auth_receive().

Only functional change in this patch is transfer buffer allocation is
moved before nvmet_check_transfer_len() and it is freed if when
nvmet_check_transfer_len() fails. But similar allocation and free is
used in error unwind path in nvme code and it is not in fast path, so
it shuold be fine.

Signed-off-by: Chaitanya Kulkarni <kch at nvidia.com>
Reviewed-by: Christoph Hellwig <hch at lst.de>
---
 drivers/nvme/target/fabrics-cmd-auth.c | 43 ++++++++++++--------------
 1 file changed, 19 insertions(+), 24 deletions(-)

diff --git a/drivers/nvme/target/fabrics-cmd-auth.c b/drivers/nvme/target/fabrics-cmd-auth.c
index 42594e086de7..778961e231a3 100644
--- a/drivers/nvme/target/fabrics-cmd-auth.c
+++ b/drivers/nvme/target/fabrics-cmd-auth.c
@@ -29,6 +29,18 @@ static u16 nvmet_auth_check_secp_spsp(struct nvmet_req *req)
 	return NVME_SC_SUCCESS;
 }
 
+static u16 nvmet_auth_alloc_transfer_buffer(struct nvmet_req *req, void **buf,
+					    u32 *len)
+{
+	*len = le32_to_cpu(req->cmd->auth_receive.al);
+	if (!*len) {
+		req->error_loc = offsetof(struct nvmf_auth_receive_command, al);
+		return NVME_SC_INVALID_FIELD | NVME_SC_DNR;
+	}
+	*buf = kmalloc(*len, GFP_KERNEL);
+	return *buf ? NVME_SC_SUCCESS : NVME_SC_INTERNAL;
+}
+
 static void nvmet_auth_expired_work(struct work_struct *work)
 {
 	struct nvmet_sq *sq = container_of(to_delayed_work(work),
@@ -207,25 +219,16 @@ void nvmet_execute_auth_send(struct nvmet_req *req)
 	status = nvmet_auth_check_secp_spsp(req);
 	if (status)
 		goto done;
-
-	tl = le32_to_cpu(req->cmd->auth_send.tl);
-	if (!tl) {
-		status = NVME_SC_INVALID_FIELD | NVME_SC_DNR;
-		req->error_loc =
-			offsetof(struct nvmf_auth_send_command, tl);
+	status = nvmet_auth_alloc_transfer_buffer(req, &d, &tl);
+	if (status)
 		goto done;
-	}
+
 	if (!nvmet_check_transfer_len(req, tl)) {
 		pr_debug("%s: transfer length mismatch (%u)\n", __func__, tl);
+		kfree(d);
 		return;
 	}
 
-	d = kmalloc(tl, GFP_KERNEL);
-	if (!d) {
-		status = NVME_SC_INTERNAL;
-		goto done;
-	}
-
 	status = nvmet_copy_from_sgl(req, 0, d, tl);
 	if (status)
 		goto done_kfree;
@@ -440,23 +443,15 @@ void nvmet_execute_auth_receive(struct nvmet_req *req)
 	status = nvmet_auth_check_secp_spsp(req);
 	if (status)
 		goto done;
-	al = le32_to_cpu(req->cmd->auth_receive.al);
-	if (!al) {
-		status = NVME_SC_INVALID_FIELD | NVME_SC_DNR;
-		req->error_loc =
-			offsetof(struct nvmf_auth_receive_command, al);
+	status = nvmet_auth_alloc_transfer_buffer(req, &d, &al);
+	if (status)
 		goto done;
-	}
 	if (!nvmet_check_transfer_len(req, al)) {
 		pr_debug("%s: transfer length mismatch (%u)\n", __func__, al);
+		kfree(d);
 		return;
 	}
 
-	d = kmalloc(al, GFP_KERNEL);
-	if (!d) {
-		status = NVME_SC_INTERNAL;
-		goto done;
-	}
 	pr_debug("%s: ctrl %d qid %d step %x\n", __func__,
 		 ctrl->cntlid, req->sq->qid, req->sq->dhchap_step);
 	switch (req->sq->dhchap_step) {
-- 
2.40.0