Michael Reed wrote:
>
> Boaz Harrosh wrote:
> <snip>
>>>> Just to demonstrate what I mean a patch is attached. Just as an RFC, totally
>>>> untested.
>>> I can try this out and see what happens.
>>>
>>>
>> Will not compile here is a cleaner one
>
> Still in my queue. Hopefully I'll get to poke at this today.
Patch compiles cleanly and appears to have no effect on the misc.
sg_* commands I've executed including sg_dd, sg_inq, sg_luns, sg_readcap.
Mike
>
> Mike
>
>> ---
>> From: Boaz Harrosh <bharrosh@xxxxxxxxxxx>
>> Date: Wed, 12 Mar 2008 13:18:49 +0200
>> Subject: [PATCH] scsi: Always complete BLOCK_PC commands
>>
>> Current code, in some IO combinations could wrongly retry
>> a BLOCK_PC command in chunks. This was never intended.
>> Fix it that BLOCK_PC will always complete atomically
>>
>> Signed-off-by: Boaz Harrosh <bharrosh@xxxxxxxxxxx>
>> ---
>> drivers/scsi/scsi_lib.c | 24 +++++++++++++-----------
>> 1 files changed, 13 insertions(+), 11 deletions(-)
>>
>> diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
>> index ba21d97..4b8b57c 100644
>> --- a/drivers/scsi/scsi_lib.c
>> +++ b/drivers/scsi/scsi_lib.c
>> @@ -784,14 +784,20 @@ EXPORT_SYMBOL(scsi_release_buffers);
>> * in req->data_len and req->next_rq->data_len. The upper-layer driver can
>> * decide what to do with this information.
>> */
>> -void scsi_end_bidi_request(struct scsi_cmnd *cmd)
>> +static void scsi_end_blk_request(struct scsi_cmnd *cmd)
>> {
>> struct request *req = cmd->request;
>> unsigned int dlen = req->data_len;
>> - unsigned int next_dlen = req->next_rq->data_len;
>> + unsigned int next_dlen;
>>
>> - req->data_len = scsi_out(cmd)->resid;
>> - req->next_rq->data_len = scsi_in(cmd)->resid;
>> + if (blk_bidi_rq(req)) {
>> + next_dlen = req->next_rq->data_len;
>> + req->data_len = scsi_out(cmd)->resid;
>> + req->next_rq->data_len = scsi_in(cmd)->resid;
>> + } else {
>> + next_dlen = 0;
>> + req->data_len = scsi_get_resid(cmd);
>> + }
>>
>> /* The req and req->next_rq have not been completed */
>> BUG_ON(blk_end_bidi_request(req, 0, dlen, next_dlen));
>> @@ -866,15 +872,11 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
>> req->sense_len = len;
>> }
>> }
>> - if (scsi_bidi_cmnd(cmd)) {
>> - /* will also release_buffers */
>> - scsi_end_bidi_request(cmd);
>> - return;
>> - }
>> - req->data_len = scsi_get_resid(cmd);
>> + /* will also release_buffers */
>> + scsi_end_blk_request(cmd);
>> + return;
>> }
>>
>> - BUG_ON(blk_bidi_rq(req)); /* bidi not support for !blk_pc_request yet */
>> scsi_release_buffers(cmd);
>>
>> /*
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