Messages in this thread | | | Date | Tue, 4 Jan 2022 09:39:33 -0700 | Subject | Re: [PATCH v3 1/3] scsi: Provide for avoiding trailing allocation length with VPD inquiries | From | Khalid Aziz and Shuah Khan <> |
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On 1/3/22 01:23, Christoph Hellwig wrote: > On Sun, Jan 02, 2022 at 11:23:45PM +0000, Maciej W. Rozycki wrote: >> Allow SCSI hosts to request avoiding trailing allocation length with VPD >> inquiries, and use the mechanism to work around an issue with at least >> some BusLogic MultiMaster host bus adapters and observed with the BT-958 >> model specifically where issuing commands that return less data than >> provided for causes fatal failures: > Wouldn't it make more sesnse to hide this quirk insde of > scsi_vpd_inquiry to also handle the scsi_get_vpd_buf case? Something > like: > > > diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c > index 211aace69c22c..194a51f772aaa 100644 > --- a/drivers/scsi/scsi.c > +++ b/drivers/scsi/scsi.c > @@ -289,8 +289,8 @@ EXPORT_SYMBOL(scsi_track_queue_full); > * > * Returns size of the vpd page on success or a negative error number. > */ > -static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer, > - u8 page, unsigned len) > +static int __scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer, > + u8 page, unsigned len) > { > int result; > unsigned char cmd[16]; > @@ -321,6 +321,20 @@ static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer, > return get_unaligned_be16(&buffer[2]) + 4; > } > > +static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer, > + u8 page, unsigned len) > +{ > + if (sdev->host->no_trailing_allocation_length) { > + int ret = __scsi_vpd_inquiry(sdev, buffer, page, min(4U, len)); > + > + if (ret < 4) > + return ret; > + len = min_t(unsigned int, ret, len); > + } > + > + return __scsi_vpd_inquiry(sdev, buffer, page, len); > +} > + > /** > * scsi_get_vpd_page - Get Vital Product Data from a SCSI device > * @sdev: The device to ask
This is certainly better. It consolidates all the special cases for getting VPD pages in one location and ensures no cases are missed.
-- Khalid
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