From c3a4d78c580de4edc9ef0f7c59812fb02ceb037f Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 7 May 2009 22:24:37 +0900 Subject: block: add rq->resid_len rq->data_len served two purposes - the length of data buffer on issue and the residual count on completion. This duality creates some headaches. First of all, block layer and low level drivers can't really determine what rq->data_len contains while a request is executing. It could be the total request length or it coulde be anything else one of the lower layers is using to keep track of residual count. This complicates things because blk_rq_bytes() and thus [__]blk_end_request_all() relies on rq->data_len for PC commands. Drivers which want to report residual count should first cache the total request length, update rq->data_len and then complete the request with the cached data length. Secondly, it makes requests default to reporting full residual count, ie. reporting that no data transfer occurred. The residual count is an exception not the norm; however, the driver should clear rq->data_len to zero to signify the normal cases while leaving it alone means no data transfer occurred at all. This reverse default behavior complicates code unnecessarily and renders block PC on some drivers (ide-tape/floppy) unuseable. This patch adds rq->resid_len which is used only for residual count. While at it, remove now unnecessasry blk_rq_bytes() caching in ide_pc_intr() as rq->data_len is not changed anymore. Boaz : spotted missing conversion in osd Sergei : spotted too early conversion to blk_rq_bytes() in ide-tape [ Impact: cleanup residual count handling, report 0 resid by default ] Signed-off-by: Tejun Heo Cc: James Bottomley Cc: Bartlomiej Zolnierkiewicz Cc: Borislav Petkov Cc: Sergei Shtylyov Cc: Mike Miller Cc: Eric Moore Cc: Alan Stern Cc: FUJITA Tomonori Cc: Doug Gilbert Cc: Mike Miller Cc: Eric Moore Cc: Darrick J. Wong Cc: Pete Zaitcev Cc: Boaz Harrosh Signed-off-by: Jens Axboe --- drivers/scsi/mpt2sas/mpt2sas_transport.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'drivers/scsi/mpt2sas') diff --git a/drivers/scsi/mpt2sas/mpt2sas_transport.c b/drivers/scsi/mpt2sas/mpt2sas_transport.c index e03dc0b1e1a..53759c566bf 100644 --- a/drivers/scsi/mpt2sas/mpt2sas_transport.c +++ b/drivers/scsi/mpt2sas/mpt2sas_transport.c @@ -1170,9 +1170,7 @@ transport_smp_handler(struct Scsi_Host *shost, struct sas_rphy *rphy, memcpy(req->sense, mpi_reply, sizeof(*mpi_reply)); req->sense_len = sizeof(*mpi_reply); - req->data_len = 0; - rsp->data_len -= mpi_reply->ResponseDataLength; - + rsp->resid_len = rsp->data_len - mpi_reply->ResponseDataLength; } else { dtransportprintk(ioc, printk(MPT2SAS_DEBUG_FMT "%s - no reply\n", ioc->name, __func__)); -- cgit v1.2.3 From b0790410300abaaf4f25f702803beff701baebf1 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 7 May 2009 22:24:42 +0900 Subject: block: cleanup rq->data_len usages With recent unification of fields, it's now guaranteed that rq->data_len always equals blk_rq_bytes(). Convert all non-IDE direct users to accessors. IDE will be converted in a separate patch. Boaz: spotted incorrect data_len/resid_len conversion in osd. [ Impact: convert direct rq->data_len usages to blk_rq_bytes() ] Signed-off-by: Tejun Heo Acked-by: Sergei Shtylyov Cc: Pete Zaitcev Cc: Eric Moore Cc: Markus Lidel Cc: Darrick J. Wong Cc: James Bottomley Cc: Eric Moore Cc: Boaz Harrosh Cc: FUJITA Tomonori Signed-off-by: Jens Axboe --- drivers/scsi/mpt2sas/mpt2sas_transport.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) (limited to 'drivers/scsi/mpt2sas') diff --git a/drivers/scsi/mpt2sas/mpt2sas_transport.c b/drivers/scsi/mpt2sas/mpt2sas_transport.c index 53759c566bf..af95a449930 100644 --- a/drivers/scsi/mpt2sas/mpt2sas_transport.c +++ b/drivers/scsi/mpt2sas/mpt2sas_transport.c @@ -1041,7 +1041,7 @@ transport_smp_handler(struct Scsi_Host *shost, struct sas_rphy *rphy, if (req->bio->bi_vcnt > 1 || rsp->bio->bi_vcnt > 1) { printk(MPT2SAS_ERR_FMT "%s: multiple segments req %u %u, " "rsp %u %u\n", ioc->name, __func__, req->bio->bi_vcnt, - req->data_len, rsp->bio->bi_vcnt, rsp->data_len); + blk_rq_bytes(req), rsp->bio->bi_vcnt, blk_rq_bytes(rsp)); return -EINVAL; } @@ -1104,7 +1104,7 @@ transport_smp_handler(struct Scsi_Host *shost, struct sas_rphy *rphy, *((u64 *)&mpi_request->SASAddress) = (rphy) ? cpu_to_le64(rphy->identify.sas_address) : cpu_to_le64(ioc->sas_hba.sas_address); - mpi_request->RequestDataLength = cpu_to_le16(req->data_len - 4); + mpi_request->RequestDataLength = cpu_to_le16(blk_rq_bytes(req) - 4); psge = &mpi_request->SGL; /* WRITE sgel first */ @@ -1112,13 +1112,13 @@ transport_smp_handler(struct Scsi_Host *shost, struct sas_rphy *rphy, MPI2_SGE_FLAGS_END_OF_BUFFER | MPI2_SGE_FLAGS_HOST_TO_IOC); sgl_flags = sgl_flags << MPI2_SGE_FLAGS_SHIFT; dma_addr_out = pci_map_single(ioc->pdev, bio_data(req->bio), - req->data_len, PCI_DMA_BIDIRECTIONAL); + blk_rq_bytes(req), PCI_DMA_BIDIRECTIONAL); if (!dma_addr_out) { mpt2sas_base_free_smid(ioc, le16_to_cpu(smid)); goto unmap; } - ioc->base_add_sg_single(psge, sgl_flags | (req->data_len - 4), + ioc->base_add_sg_single(psge, sgl_flags | (blk_rq_bytes(req) - 4), dma_addr_out); /* incr sgel */ @@ -1129,14 +1129,14 @@ transport_smp_handler(struct Scsi_Host *shost, struct sas_rphy *rphy, MPI2_SGE_FLAGS_LAST_ELEMENT | MPI2_SGE_FLAGS_END_OF_BUFFER | MPI2_SGE_FLAGS_END_OF_LIST); sgl_flags = sgl_flags << MPI2_SGE_FLAGS_SHIFT; - dma_addr_in = pci_map_single(ioc->pdev, bio_data(rsp->bio), - rsp->data_len, PCI_DMA_BIDIRECTIONAL); + dma_addr_in = pci_map_single(ioc->pdev, bio_data(rsp->bio), + blk_rq_bytes(rsp), PCI_DMA_BIDIRECTIONAL); if (!dma_addr_in) { mpt2sas_base_free_smid(ioc, le16_to_cpu(smid)); goto unmap; } - ioc->base_add_sg_single(psge, sgl_flags | (rsp->data_len + 4), + ioc->base_add_sg_single(psge, sgl_flags | (blk_rq_bytes(rsp) + 4), dma_addr_in); dtransportprintk(ioc, printk(MPT2SAS_DEBUG_FMT "%s - " @@ -1170,7 +1170,8 @@ transport_smp_handler(struct Scsi_Host *shost, struct sas_rphy *rphy, memcpy(req->sense, mpi_reply, sizeof(*mpi_reply)); req->sense_len = sizeof(*mpi_reply); - rsp->resid_len = rsp->data_len - mpi_reply->ResponseDataLength; + rsp->resid_len = blk_rq_bytes(rsp) - + mpi_reply->ResponseDataLength; } else { dtransportprintk(ioc, printk(MPT2SAS_DEBUG_FMT "%s - no reply\n", ioc->name, __func__)); @@ -1186,10 +1187,10 @@ transport_smp_handler(struct Scsi_Host *shost, struct sas_rphy *rphy, unmap: if (dma_addr_out) - pci_unmap_single(ioc->pdev, dma_addr_out, req->data_len, + pci_unmap_single(ioc->pdev, dma_addr_out, blk_rq_bytes(req), PCI_DMA_BIDIRECTIONAL); if (dma_addr_in) - pci_unmap_single(ioc->pdev, dma_addr_in, rsp->data_len, + pci_unmap_single(ioc->pdev, dma_addr_in, blk_rq_bytes(rsp), PCI_DMA_BIDIRECTIONAL); out: -- cgit v1.2.3 From 5f49f63178360b07a095bd33b0d850d60edf7590 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Tue, 19 May 2009 18:33:05 +0900 Subject: block: set rq->resid_len to blk_rq_bytes() on issue 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 request start 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 Boaz Harrosh spotted bug in resid_len initialization. Fixed as suggested. Signed-off-by: Tejun Heo Acked-by: Borislav Petkov Cc: Boaz Harrosh Cc: James Bottomley Cc: Pete Zaitcev Cc: Bartlomiej Zolnierkiewicz Cc: Sergei Shtylyov Cc: Eric Moore Cc: Darrick J. Wong Signed-off-by: Jens Axboe --- drivers/scsi/mpt2sas/mpt2sas_transport.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/scsi/mpt2sas') diff --git a/drivers/scsi/mpt2sas/mpt2sas_transport.c b/drivers/scsi/mpt2sas/mpt2sas_transport.c index af95a449930..5c65da519e3 100644 --- a/drivers/scsi/mpt2sas/mpt2sas_transport.c +++ b/drivers/scsi/mpt2sas/mpt2sas_transport.c @@ -1170,8 +1170,8 @@ transport_smp_handler(struct Scsi_Host *shost, struct sas_rphy *rphy, 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__)); -- cgit v1.2.3