From: "Darrick J. Wong" <djwong@xxxxxxxxxx>
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 <djwong@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
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
@@ -537,12 +537,11 @@ 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
_
-
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