From: "Darrick J. Wong" It turns out that libata has already dma_map_sg'd the scatterlist entries that go with an ata_queued_cmd by the time it calls sas_ata_qc_issue. sas_ata_qc_issue passes this scatterlist to aic94xx. Unfortunately, aic94xx assumes that any scatterlist passed to it needs to be pci_map_sg'd... which blows away the mapping that libata created! This causes (on a x260) Calgary IOMMU table leaks and duplicate frees when aic94xx and libata try to {pci,dma}_unmap_sg the scatterlist. Since dma_map_sg and pci_map_sg are fed the same struct device, I think it's safe to add a flag to sas_task that tells aic94xx that it need not map the scatterlist. It didn't break anything on the x260, though I don't have any SATAPI devices to test with. Is this the correct approach to fixing this problem? Signed-off-by: Darrick J. Wong Signed-off-by: Andrew Morton --- drivers/scsi/aic94xx/aic94xx_task.c | 17 +++++++++++------ drivers/scsi/libsas/sas_ata.c | 1 + include/scsi/libsas.h | 3 +-- 3 files changed, 13 insertions(+), 8 deletions(-) diff -puN drivers/scsi/aic94xx/aic94xx_task.c~aic94xx-dont-call-pci_map_sg-for-already-mapped-scatterlists drivers/scsi/aic94xx/aic94xx_task.c --- a/drivers/scsi/aic94xx/aic94xx_task.c~aic94xx-dont-call-pci_map_sg-for-already-mapped-scatterlists +++ a/drivers/scsi/aic94xx/aic94xx_task.c @@ -74,8 +74,11 @@ static inline int asd_map_scatterlist(st return 0; } - num_sg = pci_map_sg(asd_ha->pcidev, task->scatter, task->num_scatter, - task->data_dir); + if (task->external_sg) + num_sg = task->num_scatter; + else + num_sg = pci_map_sg(asd_ha->pcidev, task->scatter, + task->num_scatter, task->data_dir); if (num_sg == 0) return -ENOMEM; @@ -120,8 +123,9 @@ static inline int asd_map_scatterlist(st return 0; err_unmap: - pci_unmap_sg(asd_ha->pcidev, task->scatter, task->num_scatter, - task->data_dir); + if (!task->external_sg) + pci_unmap_sg(asd_ha->pcidev, task->scatter, task->num_scatter, + task->data_dir); return res; } @@ -142,8 +146,9 @@ static inline void asd_unmap_scatterlist } asd_free_coherent(asd_ha, ascb->sg_arr); - pci_unmap_sg(asd_ha->pcidev, task->scatter, task->num_scatter, - task->data_dir); + if (!task->external_sg) + pci_unmap_sg(asd_ha->pcidev, task->scatter, task->num_scatter, + task->data_dir); } /* ---------- Task complete tasklet ---------- */ diff -puN drivers/scsi/libsas/sas_ata.c~aic94xx-dont-call-pci_map_sg-for-already-mapped-scatterlists drivers/scsi/libsas/sas_ata.c --- a/drivers/scsi/libsas/sas_ata.c~aic94xx-dont-call-pci_map_sg-for-already-mapped-scatterlists +++ a/drivers/scsi/libsas/sas_ata.c @@ -158,6 +158,7 @@ static unsigned int sas_ata_qc_issue(str task->num_scatter = num; } + task->external_sg = 1; task->data_dir = qc->dma_dir; task->scatter = qc->__sg; task->ata_task.retry_count = 1; diff -puN include/scsi/libsas.h~aic94xx-dont-call-pci_map_sg-for-already-mapped-scatterlists include/scsi/libsas.h --- a/include/scsi/libsas.h~aic94xx-dont-call-pci_map_sg-for-already-mapped-scatterlists +++ a/include/scsi/libsas.h @@ -536,12 +536,11 @@ struct sas_task { void *lldd_task; /* for use by LLDDs */ void *uldd_task; + int external_sg; struct work_struct abort_work; }; - - #define SAS_TASK_STATE_PENDING 1 #define SAS_TASK_STATE_DONE 2 #define SAS_TASK_STATE_ABORTED 4 _