scsi: mpi3mr: Support for preallocation of SGL BSG data buffers part-1

The driver now supports SGLs for BSG data transfer. Upon loading, the
driver pre-allocates SGLs in chunks of 8k, results in a total of 256 * 8k,
equal to 2MB. These pre-allocated SGLs are reserved for handling BSG
commands and are deallocated during driver unload.
Co-developed-by: Sathya Prakash <sathya.prakash@broadcom.com>
Signed-off-by: Sathya Prakash <sathya.prakash@broadcom.com>
Signed-off-by: Chandrakanth patil <chandrakanth.patil@broadcom.com>
Link: https://lore.kernel.org/r/20231205191630.12201-2-chandrakanth.patil@broadcom.comSigned-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/mpi3mr/mpi3mr.h

@@ -477,6 +477,10 @@ struct mpi3mr_throttle_group_info {
 /* HBA port flags */
 #define MPI3MR_HBA_PORT_FLAG_DIRTY	0x01
 
+/* IOCTL data transfer sge*/
+#define MPI3MR_NUM_IOCTL_SGE		256
+#define MPI3MR_IOCTL_SGE_SIZE		(8 * 1024)
+
 /**
  * struct mpi3mr_hba_port - HBA's port information
  * @port_id: Port number
@@ -1042,6 +1046,11 @@ struct scmd_priv {
  * @sas_node_lock: Lock to protect SAS node list
  * @hba_port_table_list: List of HBA Ports
  * @enclosure_list: List of Enclosure objects
+ * @ioctl_dma_pool: DMA pool for IOCTL data buffers
+ * @ioctl_sge: DMA buffer descriptors for IOCTL data
+ * @ioctl_chain_sge: DMA buffer descriptor for IOCTL chain
+ * @ioctl_resp_sge: DMA buffer descriptor for Mgmt cmd response
+ * @ioctl_sges_allocated: Flag for IOCTL SGEs allocated or not
  */
 struct mpi3mr_ioc {
 	struct list_head list;
@@ -1227,6 +1236,12 @@ struct mpi3mr_ioc {
 	spinlock_t sas_node_lock;
 	struct list_head hba_port_table_list;
 	struct list_head enclosure_list;
+
+	struct dma_pool *ioctl_dma_pool;
+	struct dma_memory_desc ioctl_sge[MPI3MR_NUM_IOCTL_SGE];
+	struct dma_memory_desc ioctl_chain_sge;
+	struct dma_memory_desc ioctl_resp_sge;
+	bool ioctl_sges_allocated;
 };
 
 /**

drivers/scsi/mpi3mr/mpi3mr_fw.c

@@ -1058,6 +1058,114 @@ enum mpi3mr_iocstate mpi3mr_get_iocstate(struct mpi3mr_ioc *mrioc)
 	return MRIOC_STATE_RESET_REQUESTED;
 }
 
+/**
+ * mpi3mr_free_ioctl_dma_memory - free memory for ioctl dma
+ * @mrioc: Adapter instance reference
+ *
+ * Free the DMA memory allocated for IOCTL handling purpose.
+
+ *
+ * Return: None
+ */
+static void mpi3mr_free_ioctl_dma_memory(struct mpi3mr_ioc *mrioc)
+{
+	struct dma_memory_desc *mem_desc;
+	u16 i;
+
+	if (!mrioc->ioctl_dma_pool)
+		return;
+
+	for (i = 0; i < MPI3MR_NUM_IOCTL_SGE; i++) {
+		mem_desc = &mrioc->ioctl_sge[i];
+		if (mem_desc->addr) {
+			dma_pool_free(mrioc->ioctl_dma_pool,
+				      mem_desc->addr,
+				      mem_desc->dma_addr);
+			mem_desc->addr = NULL;
+		}
+	}
+	dma_pool_destroy(mrioc->ioctl_dma_pool);
+	mrioc->ioctl_dma_pool = NULL;
+	mem_desc = &mrioc->ioctl_chain_sge;
+
+	if (mem_desc->addr) {
+		dma_free_coherent(&mrioc->pdev->dev, mem_desc->size,
+				  mem_desc->addr, mem_desc->dma_addr);
+		mem_desc->addr = NULL;
+	}
+	mem_desc = &mrioc->ioctl_resp_sge;
+	if (mem_desc->addr) {
+		dma_free_coherent(&mrioc->pdev->dev, mem_desc->size,
+				  mem_desc->addr, mem_desc->dma_addr);
+		mem_desc->addr = NULL;
+	}
+
+	mrioc->ioctl_sges_allocated = false;
+}
+
+/**
+ * mpi3mr_alloc_ioctl_dma_memory - Alloc memory for ioctl dma
+ * @mrioc: Adapter instance reference
+
+ *
+ * This function allocates dmaable memory required to handle the
+ * application issued MPI3 IOCTL requests.
+ *
+ * Return: None
+ */
+static void mpi3mr_alloc_ioctl_dma_memory(struct mpi3mr_ioc *mrioc)
+
+{
+	struct dma_memory_desc *mem_desc;
+	u16 i;
+
+	mrioc->ioctl_dma_pool = dma_pool_create("ioctl dma pool",
+						&mrioc->pdev->dev,
+						MPI3MR_IOCTL_SGE_SIZE,
+						MPI3MR_PAGE_SIZE_4K, 0);
+
+	if (!mrioc->ioctl_dma_pool) {
+		ioc_err(mrioc, "ioctl_dma_pool: dma_pool_create failed\n");
+		goto out_failed;
+	}
+
+	for (i = 0; i < MPI3MR_NUM_IOCTL_SGE; i++) {
+		mem_desc = &mrioc->ioctl_sge[i];
+		mem_desc->size = MPI3MR_IOCTL_SGE_SIZE;
+		mem_desc->addr = dma_pool_zalloc(mrioc->ioctl_dma_pool,
+						 GFP_KERNEL,
+						 &mem_desc->dma_addr);
+		if (!mem_desc->addr)
+			goto out_failed;
+	}
+
+	mem_desc = &mrioc->ioctl_chain_sge;
+	mem_desc->size = MPI3MR_PAGE_SIZE_4K;
+	mem_desc->addr = dma_alloc_coherent(&mrioc->pdev->dev,
+					    mem_desc->size,
+					    &mem_desc->dma_addr,
+					    GFP_KERNEL);
+	if (!mem_desc->addr)
+		goto out_failed;
+
+	mem_desc = &mrioc->ioctl_resp_sge;
+	mem_desc->size = MPI3MR_PAGE_SIZE_4K;
+	mem_desc->addr = dma_alloc_coherent(&mrioc->pdev->dev,
+					    mem_desc->size,
+					    &mem_desc->dma_addr,
+					    GFP_KERNEL);
+	if (!mem_desc->addr)
+		goto out_failed;
+
+	mrioc->ioctl_sges_allocated = true;
+
+	return;
+out_failed:
+	ioc_warn(mrioc, "cannot allocate DMA memory for the mpt commands\n"
+		 "from the applications, application interface for MPT command is disabled\n");
+	mpi3mr_free_ioctl_dma_memory(mrioc);
+}
+
 /**
  * mpi3mr_clear_reset_history - clear reset history
  * @mrioc: Adapter instance reference
@@ -3874,6 +3982,9 @@ int mpi3mr_init_ioc(struct mpi3mr_ioc *mrioc)
 		}
 	}
 
+	dprint_init(mrioc, "allocating ioctl dma buffers\n");
+	mpi3mr_alloc_ioctl_dma_memory(mrioc);
+
 	if (!mrioc->init_cmds.reply) {
 		retval = mpi3mr_alloc_reply_sense_bufs(mrioc);
 		if (retval) {
@@ -4293,6 +4404,7 @@ void mpi3mr_free_mem(struct mpi3mr_ioc *mrioc)
 	struct mpi3mr_intr_info *intr_info;
 
 	mpi3mr_free_enclosure_list(mrioc);
+	mpi3mr_free_ioctl_dma_memory(mrioc);
 
 	if (mrioc->sense_buf_pool) {
 		if (mrioc->sense_buf)