scsi: qla2xxx: Fix use-after-free issues in qla2xxx_qpair_sp_free_dma()

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.

Cc: Himanshu Madhani <[email protected]>
Cc: Giridhar Malavali <[email protected]>
Fixes: 50b8127 ("scsi: qla2xxx: Fix DMA error when the DIF sg buffer crosses 4GB boundary") # v5.1-rc1.
Fixes: d745952 ("scsi: qla2xxx: Add multiple queue pair functionality.") # v4.10.
Signed-off-by: Bart Van Assche <[email protected]>
Acked-by: Himanshu Madhani <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>

drivers/scsi/qla2xxx/qla_os.c

@@ -764,25 +764,8 @@ 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,
@@ -816,6 +799,25 @@ 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