lkml.org 
[lkml]   [2016]   [Dec]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] scsi: do not requeue requests unaligned with device sector size
From
Date
>>>>> "Mauricio" == Mauricio Faria de Oliveira <mauricfo@linux.vnet.ibm.com> writes:

Mauricio,

Mauricio> When a SCSI command (e.g., read operation) is partially
Mauricio> completed with good status and residual bytes (i.e., not all
Mauricio> the bytes from the specified transfer length were transferred)
Mauricio> the SCSI midlayer will update the request/bios with the
Mauricio> completed bytes and requeue the request in order to complete
Mauricio> the remainder/pending bytes.

I agree with Christoph and Hannes. Some of this falls into the gray area
that's outside of the T10 spec (HBA programming interface guarantees)
but it seems like a deficiency in the HBA to report a byte count that's
not a multiple of the logical block size. A block can't be partially
written. Either it made it or it didn't. Regardless of how the I/O is
being broken up into frames at the transport level and at which offset
the transfer was interrupted.

I am also not a fan of the delayed retry stuff which seems somewhat
orthogonal to the problem you're describing.

--
Martin K. Petersen Oracle Linux Engineering

\
 
 \ /
  Last update: 2016-12-21 15:02    [W:0.145 / U:0.248 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site