[PATCH] qla2xxx: Fix use-after-free issues in qla2xxx_qpair_sp_free_dma()

[Bart Van Assche <bvanassche@xxxxxxx>]

The current order for freeing memory is as follows:
- struct crc_context itself.
- struct crc_context member pointers.

Change the freeing order into the following:
- struct crc_context member pointers.
- struct crc_context itself.

Detected by Coverity.

Untested.

Cc: Himanshu Madhani <hmadhani@xxxxxxxxxxx>
Cc: Giridhar Malavali <gmalavali@xxxxxxxxxxx>
Fixes: 50b812755e97 ("scsi: qla2xxx: Fix DMA error when the DIF sg buffer crosses 4GB boundary") # v5.1-rc1.
Fixes: d74595278f4a ("scsi: qla2xxx: Add multiple queue pair functionality.") # v4.10.
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
---
 drivers/scsi/qla2xxx/qla_os.c | 38 ++++++++++++++++++-----------------
 1 file changed, 20 insertions(+), 18 deletions(-)

diff --git a/drivers/scsi/qla2xxx/qla_os.c b/drivers/scsi/qla2xxx/qla_os.c
index b0e5484bf026..89692a839669 100644
--- a/drivers/scsi/qla2xxx/qla_os.c
+++ b/drivers/scsi/qla2xxx/qla_os.c
@@ -762,25 +762,8 @@ qla2xxx_qpair_sp_free_dma(void *ptr)
 		sp->flags &= ~SRB_CRC_CTX_DSD_VALID;
 	}
 
-	if (sp->flags & SRB_CRC_CTX_DMA_VALID) {
-		struct crc_context *ctx0 = ctx;
-
-		dma_pool_free(ha->dl_dma_pool, ctx, ctx0->crc_ctx_dma);
-		sp->flags &= ~SRB_CRC_CTX_DMA_VALID;
-	}
-
-	if (sp->flags & SRB_FCP_CMND_DMA_VALID) {
-		struct ct6_dsd *ctx1 = ctx;
-		dma_pool_free(ha->fcp_cmnd_dma_pool, ctx1->fcp_cmnd,
-		    ctx1->fcp_cmnd_dma);
-		list_splice(&ctx1->dsd_list, &ha->gbl_dsd_list);
-		ha->gbl_dsd_inuse -= ctx1->dsd_use_cnt;
-		ha->gbl_dsd_avail += ctx1->dsd_use_cnt;
-		mempool_free(ctx1, ha->ctx_mempool);
-		sp->flags &= ~SRB_FCP_CMND_DMA_VALID;
-	}
 	if (sp->flags & SRB_DIF_BUNDL_DMA_VALID) {
-		struct crc_context *difctx = sp->u.scmd.ctx;
+		struct crc_context *difctx = ctx;
 		struct dsd_dma *dif_dsd, *nxt_dsd;
 
 		list_for_each_entry_safe(dif_dsd, nxt_dsd,
@@ -814,6 +797,25 @@ qla2xxx_qpair_sp_free_dma(void *ptr)
 		}
 		sp->flags &= ~SRB_DIF_BUNDL_DMA_VALID;
 	}
+
+	if (sp->flags & SRB_FCP_CMND_DMA_VALID) {
+		struct ct6_dsd *ctx1 = ctx;
+
+		dma_pool_free(ha->fcp_cmnd_dma_pool, ctx1->fcp_cmnd,
+		    ctx1->fcp_cmnd_dma);
+		list_splice(&ctx1->dsd_list, &ha->gbl_dsd_list);
+		ha->gbl_dsd_inuse -= ctx1->dsd_use_cnt;
+		ha->gbl_dsd_avail += ctx1->dsd_use_cnt;
+		mempool_free(ctx1, ha->ctx_mempool);
+		sp->flags &= ~SRB_FCP_CMND_DMA_VALID;
+	}
+
+	if (sp->flags & SRB_CRC_CTX_DMA_VALID) {
+		struct crc_context *ctx0 = ctx;
+
+		dma_pool_free(ha->dl_dma_pool, ctx, ctx0->crc_ctx_dma);
+		sp->flags &= ~SRB_CRC_CTX_DMA_VALID;
+	}
 }
 
 void
-- 
2.21.0.196.g041f5ea1cf98