scsi: mpi3mr: Avoid MAX_PAGE_ORDER WARNING for buffer allocations

Commit fc44449 ("scsi: mpi3mr: HDB allocation and posting for hardware
and firmware buffers") added mpi3mr_alloc_diag_bufs() which calls
dma_alloc_coherent() to allocate the trace buffer and the firmware
buffer. mpi3mr_alloc_diag_bufs() decides the buffer sizes from the driver
configuration. In my environment, the sizes are 8MB. With the sizes,
dma_alloc_coherent() fails and report this WARNING:

    WARNING: CPU: 4 PID: 438 at mm/page_alloc.c:4676 __alloc_pages_noprof+0x52f/0x640

The WARNING indicates that the order of the allocation size is larger than
MAX_PAGE_ORDER. After this failure, mpi3mr_alloc_diag_bufs() reduces the
buffer sizes and retries dma_alloc_coherent(). In the end, the buffer
allocations succeed with 4MB size in my environment, which corresponds to
MAX_PAGE_ORDER=10. Though the allocations succeed, the WARNING message is
misleading and should be avoided.

To avoid the WARNING, check the orders of the buffer allocation sizes
before calling dma_alloc_coherent(). If the orders are larger than
MAX_PAGE_ORDER, fall back to the retry path.

Fixes: fc44449 ("scsi: mpi3mr: HDB allocation and posting for hardware and firmware buffers")
Signed-off-by: Shin'ichiro Kawasaki <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Acked-by: Sathya Prakash Veerichetty <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>

Author: kawasaki

drivers/scsi/mpi3mr/mpi3mr_app.c

@@ -100,7 +100,8 @@ void mpi3mr_alloc_diag_bufs(struct mpi3mr_ioc *mrioc)
 			dprint_init(mrioc,
 			    "trying to allocate trace diag buffer of size = %dKB\n",
 			    trace_size / 1024);
-		if (mpi3mr_alloc_trace_buffer(mrioc, trace_size)) {
+		if (get_order(trace_size) > MAX_PAGE_ORDER ||
+		    mpi3mr_alloc_trace_buffer(mrioc, trace_size)) {
 			retry = true;
 			trace_size -= trace_dec_size;
 			dprint_init(mrioc, "trace diag buffer allocation failed\n"
@@ -118,8 +119,12 @@ void mpi3mr_alloc_diag_bufs(struct mpi3mr_ioc *mrioc)
 	diag_buffer->type = MPI3_DIAG_BUFFER_TYPE_FW;
 	diag_buffer->status = MPI3MR_HDB_BUFSTATUS_NOT_ALLOCATED;
 	if ((mrioc->facts.diag_fw_sz < fw_size) && (fw_size >= fw_min_size)) {
-		diag_buffer->addr = dma_alloc_coherent(&mrioc->pdev->dev,
-		    fw_size, &diag_buffer->dma_addr, GFP_KERNEL);
+		if (get_order(fw_size) <= MAX_PAGE_ORDER) {
+			diag_buffer->addr
+				= dma_alloc_coherent(&mrioc->pdev->dev, fw_size,
+						     &diag_buffer->dma_addr,
+						     GFP_KERNEL);
+		}
 		if (!retry)
 			dprint_init(mrioc,
 			    "%s:trying to allocate firmware diag buffer of size = %dKB\n",