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s390/pci_dma: handle dma table failures
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We use lazy allocation for translation table entries but don't handle
allocation (and other) failures during translation table updates.

Handle these failures and undo translation table updates when it's
meaningful.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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Sebastian Ott authored and Martin Schwidefsky committed Nov 9, 2015
1 parent 4d5a6b7 commit 66728ee
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Showing 3 changed files with 48 additions and 17 deletions.
4 changes: 3 additions & 1 deletion arch/s390/include/asm/pci_dma.h
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Original file line number Diff line number Diff line change
Expand Up @@ -195,5 +195,7 @@ void zpci_dma_exit_device(struct zpci_dev *);
void dma_free_seg_table(unsigned long);
unsigned long *dma_alloc_cpu_table(void);
void dma_cleanup_tables(unsigned long *);
void dma_update_cpu_trans(unsigned long *, void *, dma_addr_t, int);
unsigned long *dma_walk_cpu_trans(unsigned long *rto, dma_addr_t dma_addr);
void dma_update_cpu_trans(unsigned long *entry, void *page_addr, int flags);

#endif
38 changes: 24 additions & 14 deletions arch/s390/pci/pci_dma.c
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Original file line number Diff line number Diff line change
Expand Up @@ -95,7 +95,7 @@ static unsigned long *dma_get_page_table_origin(unsigned long *entry)
return pto;
}

static unsigned long *dma_walk_cpu_trans(unsigned long *rto, dma_addr_t dma_addr)
unsigned long *dma_walk_cpu_trans(unsigned long *rto, dma_addr_t dma_addr)
{
unsigned long *sto, *pto;
unsigned int rtx, sx, px;
Expand All @@ -114,17 +114,8 @@ static unsigned long *dma_walk_cpu_trans(unsigned long *rto, dma_addr_t dma_addr
return &pto[px];
}

void dma_update_cpu_trans(unsigned long *dma_table, void *page_addr,
dma_addr_t dma_addr, int flags)
void dma_update_cpu_trans(unsigned long *entry, void *page_addr, int flags)
{
unsigned long *entry;

entry = dma_walk_cpu_trans(dma_table, dma_addr);
if (!entry) {
WARN_ON_ONCE(1);
return;
}

if (flags & ZPCI_PTE_INVALID) {
invalidate_pt_entry(entry);
} else {
Expand All @@ -145,18 +136,25 @@ static int dma_update_trans(struct zpci_dev *zdev, unsigned long pa,
u8 *page_addr = (u8 *) (pa & PAGE_MASK);
dma_addr_t start_dma_addr = dma_addr;
unsigned long irq_flags;
unsigned long *entry;
int i, rc = 0;

if (!nr_pages)
return -EINVAL;

spin_lock_irqsave(&zdev->dma_table_lock, irq_flags);
if (!zdev->dma_table)
if (!zdev->dma_table) {
rc = -EINVAL;
goto no_refresh;
}

for (i = 0; i < nr_pages; i++) {
dma_update_cpu_trans(zdev->dma_table, page_addr, dma_addr,
flags);
entry = dma_walk_cpu_trans(zdev->dma_table, dma_addr);
if (!entry) {
rc = -ENOMEM;
goto undo_cpu_trans;
}
dma_update_cpu_trans(entry, page_addr, flags);
page_addr += PAGE_SIZE;
dma_addr += PAGE_SIZE;
}
Expand All @@ -175,6 +173,18 @@ static int dma_update_trans(struct zpci_dev *zdev, unsigned long pa,

rc = zpci_refresh_trans((u64) zdev->fh << 32, start_dma_addr,
nr_pages * PAGE_SIZE);
undo_cpu_trans:
if (rc && ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID)) {
flags = ZPCI_PTE_INVALID;
while (i-- > 0) {
page_addr -= PAGE_SIZE;
dma_addr -= PAGE_SIZE;
entry = dma_walk_cpu_trans(zdev->dma_table, dma_addr);
if (!entry)
break;
dma_update_cpu_trans(entry, page_addr, flags);
}
}

no_refresh:
spin_unlock_irqrestore(&zdev->dma_table_lock, irq_flags);
Expand Down
23 changes: 21 additions & 2 deletions drivers/iommu/s390-iommu.c
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Original file line number Diff line number Diff line change
Expand Up @@ -216,6 +216,7 @@ static int s390_iommu_update_trans(struct s390_domain *s390_domain,
u8 *page_addr = (u8 *) (pa & PAGE_MASK);
dma_addr_t start_dma_addr = dma_addr;
unsigned long irq_flags, nr_pages, i;
unsigned long *entry;
int rc = 0;

if (dma_addr < s390_domain->domain.geometry.aperture_start ||
Expand All @@ -228,8 +229,12 @@ static int s390_iommu_update_trans(struct s390_domain *s390_domain,

spin_lock_irqsave(&s390_domain->dma_table_lock, irq_flags);
for (i = 0; i < nr_pages; i++) {
dma_update_cpu_trans(s390_domain->dma_table, page_addr,
dma_addr, flags);
entry = dma_walk_cpu_trans(s390_domain->dma_table, dma_addr);
if (!entry) {
rc = -ENOMEM;
goto undo_cpu_trans;
}
dma_update_cpu_trans(entry, page_addr, flags);
page_addr += PAGE_SIZE;
dma_addr += PAGE_SIZE;
}
Expand All @@ -242,6 +247,20 @@ static int s390_iommu_update_trans(struct s390_domain *s390_domain,
break;
}
spin_unlock(&s390_domain->list_lock);

undo_cpu_trans:
if (rc && ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID)) {
flags = ZPCI_PTE_INVALID;
while (i-- > 0) {
page_addr -= PAGE_SIZE;
dma_addr -= PAGE_SIZE;
entry = dma_walk_cpu_trans(s390_domain->dma_table,
dma_addr);
if (!entry)
break;
dma_update_cpu_trans(entry, page_addr, flags);
}
}
spin_unlock_irqrestore(&s390_domain->dma_table_lock, irq_flags);

return rc;
Expand Down

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