On 05/16/2009 03:18 AM, Tejun Heo wrote:
> In commit c3a4d78c580de4edc9ef0f7c59812fb02ceb037f, while introducing
> rq->resid_len, the default value of residue count was changed from
> full count to zero. The conversion was done under the assumption that
> when a request fails residue count wasn't defined. However, Boaz and
> James pointed out that this wasn't true and the residue count should
> be preserved for failed requests too.
>
> This patchset restores the original behavior by setting rq->resid_len
> to blk_rq_bytes(rq) on issue and restoring explicit clearing in
> affected drivers. While at it, take advantage of the fact that
> rq->resid_len is set to full count where applicable.
>
> * ide-cd: rq->resid_len cleared on pc success
>
> * mptsas: req->resid_len cleared on success
>
> * sas_expander: rsp/req->resid_len cleared on success
>
> * mpt2sas_transport: req->resid_len cleared on success
>
> * ide-cd, ide-tape, mptsas, sas_host_smp, mpt2sas_transport, ub: take
> advantage of initial full count to simplify code
>
> Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
> Cc: Jens Axboe <jens.axboe@xxxxxxxxxx>
> Cc: Boaz Harrosh <bharrosh@xxxxxxxxxxx>
> Cc: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
> Cc: Pete Zaitcev <zaitcev@xxxxxxxxxx>
> Cc: Bartlomiej Zolnierkiewicz <bzolnier@xxxxxxxxx>
> Cc: Borislav Petkov <petkovbb@xxxxxxxxxxxxxx>
> Cc: Sergei Shtylyov <sshtylyov@xxxxxxxxxxxxx>
> Cc: Eric Moore <Eric.Moore@xxxxxxx>
> Cc: Darrick J. Wong <djwong@xxxxxxxxxx>
> ---
> ub updated per Pete's comment.
>
> Thanks.
>
> block/blk-core.c | 1 +
> drivers/block/ub.c | 6 ++++--
> drivers/ide/ide-cd.c | 4 ++--
> drivers/ide/ide-tape.c | 2 +-
> drivers/message/fusion/mptsas.c | 3 ++-
> drivers/scsi/libsas/sas_expander.c | 4 ++++
> drivers/scsi/libsas/sas_host_smp.c | 3 ---
> drivers/scsi/mpt2sas/mpt2sas_transport.c | 4 ++--
> 8 files changed, 16 insertions(+), 11 deletions(-)
>
> Index: block/block/blk-core.c
> ===================================================================
> --- block.orig/block/blk-core.c
> +++ block/block/blk-core.c
> @@ -2198,6 +2198,7 @@ void blk_rq_bio_prep(struct request_queu
> rq->buffer = bio_data(bio);
> }
> rq->__data_len = bio->bi_size;
> + rq->resid_len = bio->bi_size;
> rq->bio = rq->biotail = bio;
>
Hi Tejun.
Surly this is not enough. This is not the only place rq->__data_len gets a value.
Specifically it can be added to in blk_rq_append_bio. You must then update
all places that set rq->__data_len to also set rq->resid_len.
Alternatively you could do a single:
+ rq->resid_len = blk_rq_bytes(rq);
inside blk_fetch_request(q) or before the call to prep_fn, or even at
__elv_add_request().
Currently this is a bug with chained bios
Thanks
Boaz
> if (bio->bi_bdev)
> Index: block/drivers/ide/ide-cd.c
> ===================================================================
> --- block.orig/drivers/ide/ide-cd.c
> +++ block/drivers/ide/ide-cd.c
> @@ -699,6 +699,7 @@ static ide_startstop_t cdrom_newpc_intr(
>
> out_end:
> if (blk_pc_request(rq) && rc == 0) {
> + rq->resid_len = 0;
> blk_end_request_all(rq, 0);
> hwif->rq = NULL;
> } else {
> @@ -718,8 +719,7 @@ out_end:
>
> /* make sure it's fully ended */
> if (blk_fs_request(rq) == 0) {
> - rq->resid_len = blk_rq_bytes(rq) -
> - (cmd->nbytes - cmd->nleft);
> + rq->resid_len -= cmd->nbytes - cmd->nleft;
> if (uptodate == 0 && (cmd->tf_flags & IDE_TFLAG_WRITE))
> rq->resid_len += cmd->last_xfer_len;
> }
> Index: block/drivers/ide/ide-tape.c
> ===================================================================
> --- block.orig/drivers/ide/ide-tape.c
> +++ block/drivers/ide/ide-tape.c
> @@ -380,7 +380,7 @@ static int ide_tape_callback(ide_drive_t
> }
>
> tape->first_frame += blocks;
> - rq->resid_len = blk_rq_bytes(rq) - blocks * tape->blk_size;
> + rq->resid_len -= blocks * tape->blk_size;
>
> if (pc->error) {
> uptodate = 0;
> Index: block/drivers/message/fusion/mptsas.c
> ===================================================================
> --- block.orig/drivers/message/fusion/mptsas.c
> +++ block/drivers/message/fusion/mptsas.c
> @@ -1357,7 +1357,8 @@ static int mptsas_smp_handler(struct Scs
> smprep = (SmpPassthroughReply_t *)ioc->sas_mgmt.reply;
> memcpy(req->sense, smprep, sizeof(*smprep));
> req->sense_len = sizeof(*smprep);
> - rsp->resid_len = blk_rq_bytes(rsp) - smprep->ResponseDataLength;
> + req->resid_len = 0;
> + rsp->resid_len -= smprep->ResponseDataLength;
> } else {
> printk(MYIOC_s_ERR_FMT "%s: smp passthru reply failed to be returned\n",
> ioc->name, __func__);
> Index: block/drivers/scsi/libsas/sas_expander.c
> ===================================================================
> --- block.orig/drivers/scsi/libsas/sas_expander.c
> +++ block/drivers/scsi/libsas/sas_expander.c
> @@ -1937,7 +1937,11 @@ int sas_smp_handler(struct Scsi_Host *sh
> if (ret > 0) {
> /* positive number is the untransferred residual */
> rsp->resid_len = ret;
> + req->resid_len = 0;
> ret = 0;
> + } else if (ret == 0) {
> + rsp->resid_len = 0;
> + req->resid_len = 0;
> }
>
> return ret;
> Index: block/drivers/scsi/libsas/sas_host_smp.c
> ===================================================================
> --- block.orig/drivers/scsi/libsas/sas_host_smp.c
> +++ block/drivers/scsi/libsas/sas_host_smp.c
> @@ -176,9 +176,6 @@ int sas_smp_host_handler(struct Scsi_Hos
> resp_data[1] = req_data[1];
> resp_data[2] = SMP_RESP_FUNC_UNK;
>
> - req->resid_len = blk_rq_bytes(req);
> - rsp->resid_len = blk_rq_bytes(rsp);
> -
> switch (req_data[1]) {
> case SMP_REPORT_GENERAL:
> req->resid_len -= 8;
> Index: block/drivers/scsi/mpt2sas/mpt2sas_transport.c
> ===================================================================
> --- block.orig/drivers/scsi/mpt2sas/mpt2sas_transport.c
> +++ block/drivers/scsi/mpt2sas/mpt2sas_transport.c
> @@ -1170,8 +1170,8 @@ transport_smp_handler(struct Scsi_Host *
>
> memcpy(req->sense, mpi_reply, sizeof(*mpi_reply));
> req->sense_len = sizeof(*mpi_reply);
> - rsp->resid_len = blk_rq_bytes(rsp) -
> - mpi_reply->ResponseDataLength;
> + req->resid_len = 0;
> + rsp->resid_len -= mpi_reply->ResponseDataLength;
> } else {
> dtransportprintk(ioc, printk(MPT2SAS_DEBUG_FMT
> "%s - no reply\n", ioc->name, __func__));
> Index: block/drivers/block/ub.c
> ===================================================================
> --- block.orig/drivers/block/ub.c
> +++ block/drivers/block/ub.c
> @@ -781,8 +781,10 @@ static void ub_rw_cmd_done(struct ub_dev
>
> if (cmd->error == 0) {
> if (blk_pc_request(rq)) {
> - if (cmd->act_len < blk_rq_bytes(rq))
> - rq->resid_len = blk_rq_bytes(rq) - cmd->act_len;
> + if (cmd->act_len >= rq->resid_len)
> + rq->resid_len = 0;
> + else
> + rq->resid_len -= cmd->act_len;
> scsi_status = 0;
> } else {
> if (cmd->act_len != cmd->len) {
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