[PATCH V3 2/3] nvmet_auth: use common helper for buffer alloc

[Chaitanya Kulkarni <kch@nvidia.com>]

Add a common helper to factor out buffer allocation in
nvmet_execute_auth_send() and nvmet_execute_auth_receive() and call it
from nvmet_auth_common_prep() once we done with the secp/spsp0/spsp1
check.

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@nvidia.com>
---
 drivers/nvme/target/fabrics-cmd-auth.c | 37 ++++++++++++++------------
 1 file changed, 20 insertions(+), 17 deletions(-)

diff --git a/drivers/nvme/target/fabrics-cmd-auth.c b/drivers/nvme/target/fabrics-cmd-auth.c
index 847aa12d2915..dbcae93bd25c 100644
--- a/drivers/nvme/target/fabrics-cmd-auth.c
+++ b/drivers/nvme/target/fabrics-cmd-auth.c
@@ -12,7 +12,20 @@
 #include <crypto/kpp.h>
 #include "nvmet.h"
 
-static u16 nvmet_auth_common_prep(struct nvmet_req *req)
+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 u16 nvmet_auth_common_prep(struct nvmet_req *req, void **buf,
+				  u32 *len)
 {
 	if (req->cmd->auth_send.secp != NVME_AUTH_DHCHAP_PROTOCOL_IDENTIFIER) {
 		req->error_loc = offsetof(struct nvmf_auth_send_command, secp);
@@ -26,7 +39,8 @@ static u16 nvmet_auth_common_prep(struct nvmet_req *req)
 		req->error_loc = offsetof(struct nvmf_auth_send_command, spsp1);
 		return NVME_SC_INVALID_FIELD | NVME_SC_DNR;
 	}
-	return NVME_SC_SUCCESS;
+
+	return nvmet_auth_alloc_transfer_buffer(req, buf, len);
 }
 
 static void nvmet_auth_expired_work(struct work_struct *work)
@@ -204,28 +218,16 @@ void nvmet_execute_auth_send(struct nvmet_req *req)
 	u32 tl;
 	u16 status;
 
-	status = nvmet_auth_common_prep(req);
+	status = nvmet_auth_common_prep(req, &d, &tl);
 	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);
-		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;
@@ -437,7 +439,7 @@ void nvmet_execute_auth_receive(struct nvmet_req *req)
 	u32 al;
 	u16 status;
 
-	status = nvmet_auth_common_prep(req);
+	status = nvmet_auth_common_prep(req, &d, &al);
 	if (status)
 		goto done;
 	al = le32_to_cpu(req->cmd->auth_receive.al);
@@ -449,6 +451,7 @@ void nvmet_execute_auth_receive(struct nvmet_req *req)
 	}
 	if (!nvmet_check_transfer_len(req, al)) {
 		pr_debug("%s: transfer length mismatch (%u)\n", __func__, al);
+		kfree(d);
 		return;
 	}
 
-- 
2.40.0