scsi: mpt3sas: Add app owned flag support for diag buffer

Added a new status flag named MPT3_DIAG_BUFFER_IS_APP_OWNED and it will set
whenever application registers the diag buffer & it will be cleared when
application unregisters the buffer.

When this flag is enabled, and if application issues diag buffer register
command without releasing the buffer, then register command will be failed
with -EINVAL status by saying that this buffer is already registered by the
application.

When user issues a trace buffer register command through sysfs parameter,
and if trace buffer is in released stated but not yet unregistered by the
application which was owning it, then driver will unregister the buffer by
itself and freshly register the 1MB sized trace buffer with the HBA
firmware.

Link: https://lore.kernel.org/r/1568379890-18347-9-git-send-email-sreekanth.reddy@broadcom.comSigned-off-by: Sreekanth Reddy <sreekanth.reddy@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/mpt3sas/mpt3sas_base.h

@@ -304,6 +304,7 @@ struct mpt3sas_nvme_cmd {
 #define MPT3_DIAG_BUFFER_IS_RELEASED	(0x02)
 #define MPT3_DIAG_BUFFER_IS_DIAG_RESET	(0x04)
 #define MPT3_DIAG_BUFFER_IS_DRIVER_ALLOCATED (0x08)
+#define MPT3_DIAG_BUFFER_IS_APP_OWNED (0x10)
 
 /*
  * HP HBA branding

drivers/scsi/mpt3sas/mpt3sas_ctl.c

@@ -1565,6 +1565,16 @@ _ctl_diag_register_2(struct MPT3SAS_ADAPTER *ioc,
 		return -EINVAL;
 	}
 
+	if ((ioc->diag_buffer_status[buffer_type] &
+	    MPT3_DIAG_BUFFER_IS_APP_OWNED) &&
+	    !(ioc->diag_buffer_status[buffer_type] &
+	    MPT3_DIAG_BUFFER_IS_RELEASED)) {
+		ioc_err(ioc,
+		    "%s: buffer_type(0x%02x) is already registered by application with UID(0x%08x)\n",
+		    __func__, buffer_type, ioc->unique_id[buffer_type]);
+		return -EINVAL;
+	}
+
 	if (ioc->diag_buffer_status[buffer_type] &
 	    MPT3_DIAG_BUFFER_IS_REGISTERED) {
 		/*
@@ -1884,6 +1894,12 @@ _ctl_diag_register(struct MPT3SAS_ADAPTER *ioc, void __user *arg)
 	}
 
 	rc = _ctl_diag_register_2(ioc, &karg);
+
+	if (!rc && (ioc->diag_buffer_status[karg.buffer_type] &
+	    MPT3_DIAG_BUFFER_IS_REGISTERED))
+		ioc->diag_buffer_status[karg.buffer_type] |=
+		    MPT3_DIAG_BUFFER_IS_APP_OWNED;
+
 	return rc;
 }
 
@@ -1955,6 +1971,8 @@ _ctl_diag_unregister(struct MPT3SAS_ADAPTER *ioc, void __user *arg)
 	if (ioc->diag_buffer_status[buffer_type] &
 	    MPT3_DIAG_BUFFER_IS_DRIVER_ALLOCATED) {
 		ioc->unique_id[buffer_type] = MPT3DIAGBUFFUNIQUEID;
+		ioc->diag_buffer_status[buffer_type] &=
+		    ~MPT3_DIAG_BUFFER_IS_APP_OWNED;
 		ioc->diag_buffer_status[buffer_type] &=
 		    ~MPT3_DIAG_BUFFER_IS_REGISTERED;
 	} else {
@@ -2040,6 +2058,10 @@ _ctl_diag_query(struct MPT3SAS_ADAPTER *ioc, void __user *arg)
 	    MPT3_DIAG_BUFFER_IS_DRIVER_ALLOCATED))
 		karg.application_flags |= MPT3_APP_FLAGS_DYNAMIC_BUFFER_ALLOC;
 
+	if ((ioc->diag_buffer_status[buffer_type] &
+	    MPT3_DIAG_BUFFER_IS_APP_OWNED))
+		karg.application_flags |= MPT3_APP_FLAGS_APP_OWNED;
+
 	for (i = 0; i < MPT3_PRODUCT_SPECIFIC_DWORDS; i++)
 		karg.product_specific[i] =
 		    ioc->product_specific[buffer_type][i];
@@ -3331,8 +3353,27 @@ host_trace_buffer_enable_store(struct device *cdev,
 			/* post the same buffer allocated previously */
 			diag_register.requested_buffer_size =
 			    ioc->diag_buffer_sz[MPI2_DIAG_BUF_TYPE_TRACE];
-		} else
+		} else {
+			/*
+			 * Free the diag buffer memory which was previously
+			 * allocated by an application.
+			 */
+			if ((ioc->diag_buffer_sz[MPI2_DIAG_BUF_TYPE_TRACE] != 0)
+			    &&
+			    (ioc->diag_buffer_status[MPI2_DIAG_BUF_TYPE_TRACE] &
+			    MPT3_DIAG_BUFFER_IS_APP_OWNED)) {
+				pci_free_consistent(ioc->pdev,
+				    ioc->diag_buffer_sz[
+				    MPI2_DIAG_BUF_TYPE_TRACE],
+				    ioc->diag_buffer[MPI2_DIAG_BUF_TYPE_TRACE],
+				    ioc->diag_buffer_dma[
+				    MPI2_DIAG_BUF_TYPE_TRACE]);
+				ioc->diag_buffer[MPI2_DIAG_BUF_TYPE_TRACE] =
+				    NULL;
+			}
+
 			diag_register.requested_buffer_size = (1024 * 1024);
+		}
 
 		diag_register.unique_id =
 		    (ioc->hba_mpi_version_belonged == MPI2_VERSION) ?