The suggestions look reasonable to me too.
>Arvind, since I was originally just resending your patch, do you want
>to make the changes Johannes suggests, or should I proceed with that?
> josh
Hi Josh,
Feel free to send out the updated patch if you would like.
Thanks!
Arvind
________________________________________
From: jwboyer@xxxxxxxxx <jwboyer@xxxxxxxxx> on behalf of Josh Boyer <jwboyer@xxxxxxxxxxxxxxxxx>
Sent: Wednesday, December 2, 2015 5:47 AM
To: Johannes Thumshirn
Cc: Jej B; Arvind Kumar; Thomas Hellstrom; linux-scsi@xxxxxxxxxxxxxxx; VMware PV-Drivers; Linux-Kernel@Vger. Kernel. Org
Subject: Re: [PATCH Resend] VMW_PVSCSI: Fix the issue of DMA-API related warnings.
On Wed, Dec 2, 2015 at 3:42 AM, Johannes Thumshirn <jthumshirn@xxxxxxx> wrote:
> Hi Josh,
>
> On Tue, 2015-12-01 at 11:34 -0500, Josh Boyer wrote:
>> The driver is missing calls to pci_dma_mapping_error() after
>> performing the DMA mapping, which caused DMA-API warning to
>> show up in dmesg's output. Though that happens only when
>> DMA_API_DEBUG option is enabled. This change fixes the issue
>> and makes pvscsi_map_buffers() function more robust.
>>
>> Signed-off-by: Arvind Kumar <arvindkumar@xxxxxxxxxx>
>> Cc: Josh Boyer <jwboyer@xxxxxxxxxxxxxxxxx>
>> Reviewed-by: Thomas Hellstrom <thellstrom@xxxxxxxxxx>
>> Signed-off-by: Josh Boyer <jwboyer@xxxxxxxxxxxxxxxxx>
>> ---
>>
>> - Resend of patch that was never committed for some reason
>>
>> drivers/scsi/vmw_pvscsi.c | 45 +++++++++++++++++++++++++++++++++++++++------
>> drivers/scsi/vmw_pvscsi.h | 2 +-
>> 2 files changed, 40 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/scsi/vmw_pvscsi.c b/drivers/scsi/vmw_pvscsi.c
>> index 0f133c1817de..19734494f9ec 100644
>> --- a/drivers/scsi/vmw_pvscsi.c
>> +++ b/drivers/scsi/vmw_pvscsi.c
>> @@ -349,9 +349,9 @@ static void pvscsi_create_sg(struct pvscsi_ctx *ctx,
>> * Map all data buffers for a command into PCI space and
>> * setup the scatter/gather list if needed.
>> */
>> -static void pvscsi_map_buffers(struct pvscsi_adapter *adapter,
>> - struct pvscsi_ctx *ctx, struct scsi_cmnd
>> *cmd,
>> - struct PVSCSIRingReqDesc *e)
>> +static int pvscsi_map_buffers(struct pvscsi_adapter *adapter,
>> + struct pvscsi_ctx *ctx, struct scsi_cmnd *cmd,
>> + struct PVSCSIRingReqDesc *e)
>> {
>> unsigned count;
>> unsigned bufflen = scsi_bufflen(cmd);
>> @@ -360,18 +360,30 @@ static void pvscsi_map_buffers(struct pvscsi_adapter
>> *adapter,
>> e->dataLen = bufflen;
>> e->dataAddr = 0;
>> if (bufflen == 0)
>> - return;
>> + return 0;
>>
>> sg = scsi_sglist(cmd);
>> count = scsi_sg_count(cmd);
>> if (count != 0) {
>> int segs = scsi_dma_map(cmd);
>> - if (segs > 1) {
>> +
>> + if (segs == -ENOMEM) {
>> + scmd_printk(KERN_ERR, cmd,
>> + "vmw_pvscsi: Failed to map cmd sglist
>> for DMA.\n");
>> + return -1;
>
> Please return -ENOMEM instead of -1
>
>> + } else if (segs > 1) {
>> pvscsi_create_sg(ctx, sg, segs);
>>
>> e->flags |= PVSCSI_FLAG_CMD_WITH_SG_LIST;
>> ctx->sglPA = pci_map_single(adapter->dev, ctx->sgl,
>> SGL_SIZE,
>> PCI_DMA_TODEVICE);
>> + if (pci_dma_mapping_error(adapter->dev, ctx->sglPA))
>> {
>> + scmd_printk(KERN_ERR, cmd,
>> + "vmw_pvscsi: Failed to map ctx
>> sglist for DMA.\n");
>> + scsi_dma_unmap(cmd);
>> + ctx->sglPA = 0;
>> + return -1;
>
> Same here.
>
>> + }
>> e->dataAddr = ctx->sglPA;
>> } else
>> e->dataAddr = sg_dma_address(sg);
>> @@ -382,8 +394,15 @@ static void pvscsi_map_buffers(struct pvscsi_adapter
>> *adapter,
>> */
>> ctx->dataPA = pci_map_single(adapter->dev, sg, bufflen,
>> cmd->sc_data_direction);
>> + if (pci_dma_mapping_error(adapter->dev, ctx->dataPA)) {
>> + scmd_printk(KERN_ERR, cmd,
>> + "vmw_pvscsi: Failed to map direct data
>> buffer for DMA.\n");
>> + return -1;
>
> And here.
>
>> + }
>> e->dataAddr = ctx->dataPA;
>> }
>> +
>> + return 0;
>> }
>>
>> static void pvscsi_unmap_buffers(const struct pvscsi_adapter *adapter,
>> @@ -690,6 +709,12 @@ static int pvscsi_queue_ring(struct pvscsi_adapter
>> *adapter,
>> ctx->sensePA = pci_map_single(adapter->dev, cmd-
>> >sense_buffer,
>> SCSI_SENSE_BUFFERSIZE,
>> PCI_DMA_FROMDEVICE);
>> + if (pci_dma_mapping_error(adapter->dev, ctx->sensePA)) {
>> + scmd_printk(KERN_ERR, cmd,
>> + "vmw_pvscsi: Failed to map sense buffer
>> for DMA.\n");
>> + ctx->sensePA = 0;
>> + return -1;
>
> And here.
>
>> + }
>> e->senseAddr = ctx->sensePA;
>> e->senseLen = SCSI_SENSE_BUFFERSIZE;
>> } else {
>> @@ -711,7 +736,15 @@ static int pvscsi_queue_ring(struct pvscsi_adapter
>> *adapter,
>> else
>> e->flags = 0;
>>
>> - pvscsi_map_buffers(adapter, ctx, cmd, e);
>> + if (pvscsi_map_buffers(adapter, ctx, cmd, e) != 0) {
>> + if (cmd->sense_buffer) {
>> + pci_unmap_single(adapter->dev, ctx->sensePA,
>> + SCSI_SENSE_BUFFERSIZE,
>> + PCI_DMA_FROMDEVICE);
>> + ctx->sensePA = 0;
>> + }
>> + return -1;
>
> As pvscsi_map_buffers() only returns 0 or -ENOMEM please return -ENOMEM here as
> well, or do
>
> int err;
> [...]
> err = pvscsi_map_buffers(adapter, ctx, cmd, e);
> if (err) {
> [...]
> return err;
> }
>
Thanks for the suggestions. They all seem reasonable to me.
Arvind, since I was originally just resending your patch, do you want
to make the changes Johannes suggests, or should I proceed with that?
josh
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