RE: [PATCH] scsi: megaraid_sas: handle dma_addr_t right on 32-bit

[Sumit Saxena <sumit.saxena@broadcom.com>]

>-----Original Message-----
>From: Arnd Bergmann [mailto:arnd@arndb.de]
>Sent: Wednesday, February 15, 2017 2:52 AM
>To: James E.J. Bottomley; Martin K. Petersen
>Cc: Arnd Bergmann; Kashyap Desai; Sumit Saxena; Shivasharan S; Tomas
Henzl;
>Hannes Reinecke; Sasikumar Chandrasekaran;
>megaraidlinux.pdl@broadcom.com; linux-scsi@vger.kernel.org; linux-
>kernel@vger.kernel.org
>Subject: [PATCH] scsi: megaraid_sas: handle dma_addr_t right on 32-bit
>
>When building with a dma_addr_t that is different from pointer size, we
get this
>warning:
>
>drivers/scsi/megaraid/megaraid_sas_fusion.c: In function
>'megasas_make_prp_nvme':
>drivers/scsi/megaraid/megaraid_sas_fusion.c:1654:17: error: cast to
pointer
>from integer of different size [-Werror=int-to-pointer-cast]
>
>It's better to not pretend that the dma address is a pointer and instead
use a
>dma_addr_t consistently.

Patch looks good from review but we need to have some test runs before
acking this.
I will get back after some test runs.

Thanks,
Sumit
>
>Fixes: 33203bc4d61b ("scsi: megaraid_sas: NVME fast path io support")
>Signed-off-by: Arnd Bergmann <arnd@arndb.de>
>---
> drivers/scsi/megaraid/megaraid_sas_fusion.c | 14 +++++++-------
> 1 file changed, 7 insertions(+), 7 deletions(-)
>
>diff --git a/drivers/scsi/megaraid/megaraid_sas_fusion.c
>b/drivers/scsi/megaraid/megaraid_sas_fusion.c
>index 750090119f81..29650ba669da 100644
>--- a/drivers/scsi/megaraid/megaraid_sas_fusion.c
>+++ b/drivers/scsi/megaraid/megaraid_sas_fusion.c
>@@ -1619,7 +1619,8 @@ megasas_make_prp_nvme(struct megasas_instance
>*instance, struct scsi_cmnd *scmd,  {
> 	int sge_len, offset, num_prp_in_chain = 0;
> 	struct MPI25_IEEE_SGE_CHAIN64 *main_chain_element, *ptr_first_sgl;
>-	u64 *ptr_sgl, *ptr_sgl_phys;
>+	u64 *ptr_sgl;
>+	dma_addr_t ptr_sgl_phys;
> 	u64 sge_addr;
> 	u32 page_mask, page_mask_result;
> 	struct scatterlist *sg_scmd;
>@@ -1651,14 +1652,14 @@ megasas_make_prp_nvme(struct megasas_instance
>*instance, struct scsi_cmnd *scmd,
> 	 */
> 	page_mask = mr_nvme_pg_size - 1;
> 	ptr_sgl = (u64 *)cmd->sg_frame;
>-	ptr_sgl_phys = (u64 *)cmd->sg_frame_phys_addr;
>+	ptr_sgl_phys = cmd->sg_frame_phys_addr;
> 	memset(ptr_sgl, 0, instance->max_chain_frame_sz);
>
> 	/* Build chain frame element which holds all prps except first*/
> 	main_chain_element = (struct MPI25_IEEE_SGE_CHAIN64 *)
> 	    ((u8 *)sgl_ptr + sizeof(struct MPI25_IEEE_SGE_CHAIN64));
>
>-	main_chain_element->Address =
cpu_to_le64((uintptr_t)ptr_sgl_phys);
>+	main_chain_element->Address = cpu_to_le64(ptr_sgl_phys);
> 	main_chain_element->NextChainOffset = 0;
> 	main_chain_element->Flags = IEEE_SGE_FLAGS_CHAIN_ELEMENT |
> 					IEEE_SGE_FLAGS_SYSTEM_ADDR |
>@@ -1696,16 +1697,15 @@ megasas_make_prp_nvme(struct megasas_instance
>*instance, struct scsi_cmnd *scmd,
> 			scmd_printk(KERN_NOTICE,
> 				    scmd, "page boundary ptr_sgl: 0x%p\n",
> 				    ptr_sgl);
>-			ptr_sgl_phys++;
>-			*ptr_sgl =
>-				cpu_to_le64((uintptr_t)ptr_sgl_phys);
>+			ptr_sgl_phys += 8;
>+			*ptr_sgl = cpu_to_le64(ptr_sgl_phys);
> 			ptr_sgl++;
> 			num_prp_in_chain++;
> 		}
>
> 		*ptr_sgl = cpu_to_le64(sge_addr);
> 		ptr_sgl++;
>-		ptr_sgl_phys++;
>+		ptr_sgl_phys += 8;
> 		num_prp_in_chain++;
>
> 		sge_addr += mr_nvme_pg_size;
>--
>2.9.0