From: Christoph Hellwig <hch@infradead.org>
To: Alexey Khoroshilov <khoroshilov@ispras.ru>
Cc: "James E.J. Bottomley" <jejb@linux.vnet.ibm.com>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org,
ldv-project@linuxtesting.org
Subject: Re: [PATCH] scsi: mvumi: add check for dma mapping errors
Date: Sun, 23 Apr 2017 01:41:33 -0700 [thread overview]
Message-ID: <20170423084133.GE30869@infradead.org> (raw)
In-Reply-To: <1492816670-25795-1-git-send-email-khoroshilov@ispras.ru>
On Sat, Apr 22, 2017 at 02:17:50AM +0300, Alexey Khoroshilov wrote:
> } else {
> - scmd->SCp.dma_handle = scsi_bufflen(scmd) ?
> - pci_map_single(mhba->pdev, scsi_sglist(scmd),
> - scsi_bufflen(scmd),
> - (int) scmd->sc_data_direction)
> - : 0;
> + if (!scsi_bufflen(scmd))
> + return -1;
> + scmd->SCp.dma_handle = pci_map_single(mhba->pdev,
> + scsi_sglist(scmd),
> + scsi_bufflen(scmd),
> + (int) scmd->sc_data_direction);
> + if (pci_dma_mapping_error(mhba->pdev, scmd->SCp.dma_handle))
> + return -1;
This looks completely broken. Why would you DMA map the in-memory
struct scatterlist? It has no meaning for the hardware.
In fact this whole branch (and the equivalent in the unmap path)
are dead - SCSI commands that transfer data always have a SG entry.
So the right fix is to remove the !scsi_sg_count(scmd) map/unmap
path.
next prev parent reply other threads:[~2017-04-23 8:41 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-21 23:17 [PATCH] scsi: mvumi: add check for dma mapping errors Alexey Khoroshilov
2017-04-23 8:41 ` Christoph Hellwig [this message]
2017-04-23 23:01 ` [PATCH] scsi: mvumi: remove code handling zero scsi_sg_count(scmd) case Alexey Khoroshilov
2017-04-24 6:36 ` Christoph Hellwig
2017-04-24 22:17 ` Martin K. Petersen
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