[PATCH, 5.8 regression] mptfusion: don't use GFP_ATOMIC for larger DMA allocations

[PATCH, 5.8 regression] mptfusion: don't use GFP_ATOMIC for larger DMA allocations

[Christoph Hellwig]

The mpt fusion driver still uses the legacy PCI DMA API, which hardcodes
atomic allocations.  This caused the driver to fail to load on some
powerpc VMs with incoherent DMA and small memory sizes.  Switch to use
the modern DMA API and sleeping allocations for large allocations
instead.  This is not a full cleanup of the PCI DMA API usage yet, but
just enough to fix the regression caused by reducing the default atomic
pool size.

Fixes: 3ee06a6d532f ("dma-pool: fix too large DMA pools on medium memory size systems")
Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Guenter Roeck <linux@roeck-us.net>
---
 drivers/message/fusion/mptbase.c | 41 ++++++++++++++++----------------
 1 file changed, 20 insertions(+), 21 deletions(-)

diff --git a/drivers/message/fusion/mptbase.c b/drivers/message/fusion/mptbase.c
index 68aea22f2b8978..5216487db4fbea 100644
--- a/drivers/message/fusion/mptbase.c
+++ b/drivers/message/fusion/mptbase.c
@@ -1324,13 +1324,13 @@ mpt_host_page_alloc(MPT_ADAPTER *ioc, pIOCInit_t ioc_init)
 			return 0; /* fw doesn't need any host buffers */
 
 		/* spin till we get enough memory */
-		while(host_page_buffer_sz > 0) {
-
-			if((ioc->HostPageBuffer = pci_alloc_consistent(
-			    ioc->pcidev,
-			    host_page_buffer_sz,
-			    &ioc->HostPageBuffer_dma)) != NULL) {
-
+		while (host_page_buffer_sz > 0) {
+			ioc->HostPageBuffer =
+				dma_alloc_coherent(&ioc->pcidev->dev,
+						host_page_buffer_sz,
+						&ioc->HostPageBuffer_dma,
+						GFP_KERNEL);
+			if (ioc->HostPageBuffer) {
 				dinitprintk(ioc, printk(MYIOC_s_DEBUG_FMT
 				    "host_page_buffer @ %p, dma @ %x, sz=%d bytes\n",
 				    ioc->name, ioc->HostPageBuffer,
@@ -2741,8 +2741,8 @@ mpt_adapter_disable(MPT_ADAPTER *ioc)
 		sz = ioc->alloc_sz;
 		dexitprintk(ioc, printk(MYIOC_s_INFO_FMT "free  @ %p, sz=%d bytes\n",
 		    ioc->name, ioc->alloc, ioc->alloc_sz));
-		pci_free_consistent(ioc->pcidev, sz,
-				ioc->alloc, ioc->alloc_dma);
+		dma_free_coherent(&ioc->pcidev->dev, sz, ioc->alloc,
+				ioc->alloc_dma);
 		ioc->reply_frames = NULL;
 		ioc->req_frames = NULL;
 		ioc->alloc = NULL;
@@ -2751,8 +2751,8 @@ mpt_adapter_disable(MPT_ADAPTER *ioc)
 
 	if (ioc->sense_buf_pool != NULL) {
 		sz = (ioc->req_depth * MPT_SENSE_BUFFER_ALLOC);
-		pci_free_consistent(ioc->pcidev, sz,
-				ioc->sense_buf_pool, ioc->sense_buf_pool_dma);
+		dma_free_coherent(&ioc->pcidev->dev, sz, ioc->sense_buf_pool,
+				ioc->sense_buf_pool_dma);
 		ioc->sense_buf_pool = NULL;
 		ioc->alloc_total -= sz;
 	}
@@ -2802,7 +2802,7 @@ mpt_adapter_disable(MPT_ADAPTER *ioc)
 			"HostPageBuffer free  @ %p, sz=%d bytes\n",
 			ioc->name, ioc->HostPageBuffer,
 			ioc->HostPageBuffer_sz));
-		pci_free_consistent(ioc->pcidev, ioc->HostPageBuffer_sz,
+		dma_free_coherent(&ioc->pcidev->dev, ioc->HostPageBuffer_sz,
 		    ioc->HostPageBuffer, ioc->HostPageBuffer_dma);
 		ioc->HostPageBuffer = NULL;
 		ioc->HostPageBuffer_sz = 0;
@@ -4497,7 +4497,8 @@ PrimeIocFifos(MPT_ADAPTER *ioc)
 			 	ioc->name, sz, sz, num_chain));
 
 		total_size += sz;
-		mem = pci_alloc_consistent(ioc->pcidev, total_size, &alloc_dma);
+		mem = dma_alloc_coherent(&ioc->pcidev->dev, total_size,
+				&alloc_dma, GFP_KERNEL);
 		if (mem == NULL) {
 			printk(MYIOC_s_ERR_FMT "Unable to allocate Reply, Request, Chain Buffers!\n",
 				ioc->name);
@@ -4574,8 +4575,8 @@ PrimeIocFifos(MPT_ADAPTER *ioc)
 		spin_unlock_irqrestore(&ioc->FreeQlock, flags);
 
 		sz = (ioc->req_depth * MPT_SENSE_BUFFER_ALLOC);
-		ioc->sense_buf_pool =
-			pci_alloc_consistent(ioc->pcidev, sz, &ioc->sense_buf_pool_dma);
+		ioc->sense_buf_pool = dma_alloc_coherent(&ioc->pcidev->dev, sz,
+				&ioc->sense_buf_pool_dma, GFP_KERNEL);
 		if (ioc->sense_buf_pool == NULL) {
 			printk(MYIOC_s_ERR_FMT "Unable to allocate Sense Buffers!\n",
 				ioc->name);
@@ -4613,18 +4614,16 @@ PrimeIocFifos(MPT_ADAPTER *ioc)
 
 	if (ioc->alloc != NULL) {
 		sz = ioc->alloc_sz;
-		pci_free_consistent(ioc->pcidev,
-				sz,
-				ioc->alloc, ioc->alloc_dma);
+		dma_free_coherent(&ioc->pcidev->dev, sz, ioc->alloc,
+				ioc->alloc_dma);
 		ioc->reply_frames = NULL;
 		ioc->req_frames = NULL;
 		ioc->alloc_total -= sz;
 	}
 	if (ioc->sense_buf_pool != NULL) {
 		sz = (ioc->req_depth * MPT_SENSE_BUFFER_ALLOC);
-		pci_free_consistent(ioc->pcidev,
-				sz,
-				ioc->sense_buf_pool, ioc->sense_buf_pool_dma);
+		dma_free_coherent(&ioc->pcidev->dev, sz, ioc->sense_buf_pool,
+				ioc->sense_buf_pool_dma);
 		ioc->sense_buf_pool = NULL;
 	}
 
-- 
2.26.2

Re: [PATCH, 5.8 regression] mptfusion: don't use GFP_ATOMIC for larger DMA allocations

[Martin K. Petersen]

On Wed, 24 Jun 2020 18:57:24 +0200, Christoph Hellwig wrote:

> The mpt fusion driver still uses the legacy PCI DMA API, which hardcodes
> atomic allocations.  This caused the driver to fail to load on some
> powerpc VMs with incoherent DMA and small memory sizes.  Switch to use
> the modern DMA API and sleeping allocations for large allocations
> instead.  This is not a full cleanup of the PCI DMA API usage yet, but
> just enough to fix the regression caused by reducing the default atomic
> pool size.

Applied to 5.8/scsi-fixes, thanks!

[1/1] scsi: mptfusion: Don't use GFP_ATOMIC for larger DMA allocations
      https://git.kernel.org/mkp/scsi/c/311950f8b8d8

-- 
Martin K. Petersen	Oracle Linux Engineering