diff options
author | David S. Miller <davem@huronp11.davemloft.net> | 2008-02-06 03:50:26 -0800 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2008-02-06 04:12:25 -0800 |
commit | 38192d52f159bc06b7f523800c10b583cdd661d5 (patch) | |
tree | 4cf695d583c0a657133642c0299cbfa536e25663 /arch | |
parent | b3ff81dd8ae29ec431f6cc91aff601a51ef6fb8c (diff) | |
download | linux-38192d52f159bc06b7f523800c10b583cdd661d5.tar.bz2 |
[SPARC64]: Temporarily remove IOMMU merging code.
Changeset fde6a3c82d67f592eb587be4d12222b0ae6d4321 ("iommu sg merging:
sparc64: make iommu respect the segment size limits") broke sparc64
because whilst it added the segment limiting code to the first pass of
SG mapping (in prepare_sg()) it did not add matching code to the
second pass handling (in fill_sg())
As a result the two passes disagree where the segment boundaries
should be, resulting in OOPSes, DMA corruption, and corrupted
superblocks.
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'arch')
-rw-r--r-- | arch/sparc64/kernel/Makefile | 2 | ||||
-rw-r--r-- | arch/sparc64/kernel/iommu.c | 142 | ||||
-rw-r--r-- | arch/sparc64/kernel/iommu_common.c | 248 | ||||
-rw-r--r-- | arch/sparc64/kernel/iommu_common.h | 26 | ||||
-rw-r--r-- | arch/sparc64/kernel/pci_sun4v.c | 170 |
5 files changed, 92 insertions, 496 deletions
diff --git a/arch/sparc64/kernel/Makefile b/arch/sparc64/kernel/Makefile index ef50d217432f..4b78b24ef413 100644 --- a/arch/sparc64/kernel/Makefile +++ b/arch/sparc64/kernel/Makefile @@ -11,7 +11,7 @@ obj-y := process.o setup.o cpu.o idprom.o \ traps.o auxio.o una_asm.o sysfs.o iommu.o \ irq.o ptrace.o time.o sys_sparc.o signal.o \ unaligned.o central.o pci.o starfire.o semaphore.o \ - power.o sbus.o iommu_common.o sparc64_ksyms.o chmc.o \ + power.o sbus.o sparc64_ksyms.o chmc.o \ visemul.o prom.o of_device.o hvapi.o sstate.o mdesc.o obj-$(CONFIG_STACKTRACE) += stacktrace.o diff --git a/arch/sparc64/kernel/iommu.c b/arch/sparc64/kernel/iommu.c index 4b9115a4d92e..5623a4d59dff 100644 --- a/arch/sparc64/kernel/iommu.c +++ b/arch/sparc64/kernel/iommu.c @@ -472,94 +472,15 @@ static void dma_4u_unmap_single(struct device *dev, dma_addr_t bus_addr, spin_unlock_irqrestore(&iommu->lock, flags); } -#define SG_ENT_PHYS_ADDRESS(SG) (__pa(sg_virt((SG)))) - -static void fill_sg(iopte_t *iopte, struct scatterlist *sg, - int nused, int nelems, - unsigned long iopte_protection) -{ - struct scatterlist *dma_sg = sg; - int i; - - for (i = 0; i < nused; i++) { - unsigned long pteval = ~0UL; - u32 dma_npages; - - dma_npages = ((dma_sg->dma_address & (IO_PAGE_SIZE - 1UL)) + - dma_sg->dma_length + - ((IO_PAGE_SIZE - 1UL))) >> IO_PAGE_SHIFT; - do { - unsigned long offset; - signed int len; - - /* If we are here, we know we have at least one - * more page to map. So walk forward until we - * hit a page crossing, and begin creating new - * mappings from that spot. - */ - for (;;) { - unsigned long tmp; - - tmp = SG_ENT_PHYS_ADDRESS(sg); - len = sg->length; - if (((tmp ^ pteval) >> IO_PAGE_SHIFT) != 0UL) { - pteval = tmp & IO_PAGE_MASK; - offset = tmp & (IO_PAGE_SIZE - 1UL); - break; - } - if (((tmp ^ (tmp + len - 1UL)) >> IO_PAGE_SHIFT) != 0UL) { - pteval = (tmp + IO_PAGE_SIZE) & IO_PAGE_MASK; - offset = 0UL; - len -= (IO_PAGE_SIZE - (tmp & (IO_PAGE_SIZE - 1UL))); - break; - } - sg = sg_next(sg); - nelems--; - } - - pteval = iopte_protection | (pteval & IOPTE_PAGE); - while (len > 0) { - *iopte++ = __iopte(pteval); - pteval += IO_PAGE_SIZE; - len -= (IO_PAGE_SIZE - offset); - offset = 0; - dma_npages--; - } - - pteval = (pteval & IOPTE_PAGE) + len; - sg = sg_next(sg); - nelems--; - - /* Skip over any tail mappings we've fully mapped, - * adjusting pteval along the way. Stop when we - * detect a page crossing event. - */ - while (nelems && - (pteval << (64 - IO_PAGE_SHIFT)) != 0UL && - (pteval == SG_ENT_PHYS_ADDRESS(sg)) && - ((pteval ^ - (SG_ENT_PHYS_ADDRESS(sg) + sg->length - 1UL)) >> IO_PAGE_SHIFT) == 0UL) { - pteval += sg->length; - sg = sg_next(sg); - nelems--; - } - if ((pteval << (64 - IO_PAGE_SHIFT)) == 0UL) - pteval = ~0UL; - } while (dma_npages != 0); - dma_sg = sg_next(dma_sg); - } -} - static int dma_4u_map_sg(struct device *dev, struct scatterlist *sglist, int nelems, enum dma_data_direction direction) { - struct iommu *iommu; + unsigned long flags, ctx, i, npages, iopte_protection; + struct scatterlist *sg; struct strbuf *strbuf; - unsigned long flags, ctx, npages, iopte_protection; + struct iommu *iommu; iopte_t *base; u32 dma_base; - struct scatterlist *sgtmp; - int used; /* Fast path single entry scatterlists. */ if (nelems == 1) { @@ -578,11 +499,7 @@ static int dma_4u_map_sg(struct device *dev, struct scatterlist *sglist, if (unlikely(direction == DMA_NONE)) goto bad_no_ctx; - /* Step 1: Prepare scatter list. */ - - npages = prepare_sg(dev, sglist, nelems); - - /* Step 2: Allocate a cluster and context, if necessary. */ + npages = calc_npages(sglist, nelems); spin_lock_irqsave(&iommu->lock, flags); @@ -599,18 +516,6 @@ static int dma_4u_map_sg(struct device *dev, struct scatterlist *sglist, dma_base = iommu->page_table_map_base + ((base - iommu->page_table) << IO_PAGE_SHIFT); - /* Step 3: Normalize DMA addresses. */ - used = nelems; - - sgtmp = sglist; - while (used && sgtmp->dma_length) { - sgtmp->dma_address += dma_base; - sgtmp = sg_next(sgtmp); - used--; - } - used = nelems - used; - - /* Step 4: Create the mappings. */ if (strbuf->strbuf_enabled) iopte_protection = IOPTE_STREAMING(ctx); else @@ -618,13 +523,27 @@ static int dma_4u_map_sg(struct device *dev, struct scatterlist *sglist, if (direction != DMA_TO_DEVICE) iopte_protection |= IOPTE_WRITE; - fill_sg(base, sglist, used, nelems, iopte_protection); + for_each_sg(sglist, sg, nelems, i) { + unsigned long paddr = SG_ENT_PHYS_ADDRESS(sg); + unsigned long slen = sg->length; + unsigned long this_npages; -#ifdef VERIFY_SG - verify_sglist(sglist, nelems, base, npages); -#endif + this_npages = iommu_num_pages(paddr, slen); - return used; + sg->dma_address = dma_base | (paddr & ~IO_PAGE_MASK); + sg->dma_length = slen; + + paddr &= IO_PAGE_MASK; + while (this_npages--) { + iopte_val(*base) = iopte_protection | paddr; + + base++; + paddr += IO_PAGE_SIZE; + dma_base += IO_PAGE_SIZE; + } + } + + return nelems; bad: iommu_free_ctx(iommu, ctx); @@ -637,11 +556,10 @@ bad_no_ctx: static void dma_4u_unmap_sg(struct device *dev, struct scatterlist *sglist, int nelems, enum dma_data_direction direction) { - struct iommu *iommu; + unsigned long flags, ctx, i, npages; struct strbuf *strbuf; + struct iommu *iommu; iopte_t *base; - unsigned long flags, ctx, i, npages; - struct scatterlist *sg, *sgprv; u32 bus_addr; if (unlikely(direction == DMA_NONE)) { @@ -654,15 +572,7 @@ static void dma_4u_unmap_sg(struct device *dev, struct scatterlist *sglist, bus_addr = sglist->dma_address & IO_PAGE_MASK; - sgprv = NULL; - for_each_sg(sglist, sg, nelems, i) { - if (sg->dma_length == 0) - break; - sgprv = sg; - } - - npages = (IO_PAGE_ALIGN(sgprv->dma_address + sgprv->dma_length) - - bus_addr) >> IO_PAGE_SHIFT; + npages = calc_npages(sglist, nelems); base = iommu->page_table + ((bus_addr - iommu->page_table_map_base) >> IO_PAGE_SHIFT); diff --git a/arch/sparc64/kernel/iommu_common.c b/arch/sparc64/kernel/iommu_common.c deleted file mode 100644 index 72a4acfe8c7b..000000000000 --- a/arch/sparc64/kernel/iommu_common.c +++ /dev/null @@ -1,248 +0,0 @@ -/* $Id: iommu_common.c,v 1.9 2001/12/17 07:05:09 davem Exp $ - * iommu_common.c: UltraSparc SBUS/PCI common iommu code. - * - * Copyright (C) 1999 David S. Miller (davem@redhat.com) - */ - -#include <linux/dma-mapping.h> -#include "iommu_common.h" - -/* You are _strongly_ advised to enable the following debugging code - * any time you make changes to the sg code below, run it for a while - * with filesystems mounted read-only before buying the farm... -DaveM - */ - -#ifdef VERIFY_SG -static int verify_lengths(struct scatterlist *sglist, int nents, int npages) -{ - int sg_len, dma_len; - int i, pgcount; - struct scatterlist *sg; - - sg_len = 0; - for_each_sg(sglist, sg, nents, i) - sg_len += sg->length; - - dma_len = 0; - for_each_sg(sglist, sg, nents, i) { - if (!sg->dma_length) - break; - dma_len += sg->dma_length; - } - - if (sg_len != dma_len) { - printk("verify_lengths: Error, different, sg[%d] dma[%d]\n", - sg_len, dma_len); - return -1; - } - - pgcount = 0; - for_each_sg(sglist, sg, nents, i) { - unsigned long start, end; - - if (!sg->dma_length) - break; - - start = sg->dma_address; - start = start & IO_PAGE_MASK; - - end = sg->dma_address + sg->dma_length; - end = (end + (IO_PAGE_SIZE - 1)) & IO_PAGE_MASK; - - pgcount += ((end - start) >> IO_PAGE_SHIFT); - } - - if (pgcount != npages) { - printk("verify_lengths: Error, page count wrong, " - "npages[%d] pgcount[%d]\n", - npages, pgcount); - return -1; - } - - /* This test passes... */ - return 0; -} - -static int verify_one_map(struct scatterlist *dma_sg, struct scatterlist **__sg, int nents, iopte_t **__iopte) -{ - struct scatterlist *sg = *__sg; - iopte_t *iopte = *__iopte; - u32 dlen = dma_sg->dma_length; - u32 daddr; - unsigned int sglen; - unsigned long sgaddr; - - daddr = dma_sg->dma_address; - sglen = sg->length; - sgaddr = (unsigned long) sg_virt(sg); - while (dlen > 0) { - unsigned long paddr; - - /* SG and DMA_SG must begin at the same sub-page boundary. */ - if ((sgaddr & ~IO_PAGE_MASK) != (daddr & ~IO_PAGE_MASK)) { - printk("verify_one_map: Wrong start offset " - "sg[%08lx] dma[%08x]\n", - sgaddr, daddr); - nents = -1; - goto out; - } - - /* Verify the IOPTE points to the right page. */ - paddr = iopte_val(*iopte) & IOPTE_PAGE; - if ((paddr + PAGE_OFFSET) != (sgaddr & IO_PAGE_MASK)) { - printk("verify_one_map: IOPTE[%08lx] maps the " - "wrong page, should be [%08lx]\n", - iopte_val(*iopte), (sgaddr & IO_PAGE_MASK) - PAGE_OFFSET); - nents = -1; - goto out; - } - - /* If this SG crosses a page, adjust to that next page - * boundary and loop. - */ - if ((sgaddr & IO_PAGE_MASK) ^ ((sgaddr + sglen - 1) & IO_PAGE_MASK)) { - unsigned long next_page, diff; - - next_page = (sgaddr + IO_PAGE_SIZE) & IO_PAGE_MASK; - diff = next_page - sgaddr; - sgaddr += diff; - daddr += diff; - sglen -= diff; - dlen -= diff; - if (dlen > 0) - iopte++; - continue; - } - - /* SG wholly consumed within this page. */ - daddr += sglen; - dlen -= sglen; - - if (dlen > 0 && ((daddr & ~IO_PAGE_MASK) == 0)) - iopte++; - - sg = sg_next(sg); - if (--nents <= 0) - break; - sgaddr = (unsigned long) sg_virt(sg); - sglen = sg->length; - } - if (dlen < 0) { - /* Transfer overrun, big problems. */ - printk("verify_one_map: Transfer overrun by %d bytes.\n", - -dlen); - nents = -1; - } else { - /* Advance to next dma_sg implies that the next iopte will - * begin it. - */ - iopte++; - } - -out: - *__sg = sg; - *__iopte = iopte; - return nents; -} - -static int verify_maps(struct scatterlist *sg, int nents, iopte_t *iopte) -{ - struct scatterlist *dma_sg = sg; - struct scatterlist *orig_dma_sg = dma_sg; - int orig_nents = nents; - - for (;;) { - nents = verify_one_map(dma_sg, &sg, nents, &iopte); - if (nents <= 0) - break; - dma_sg = sg_next(dma_sg); - if (dma_sg->dma_length == 0) - break; - } - - if (nents > 0) { - printk("verify_maps: dma maps consumed by some sgs remain (%d)\n", - nents); - return -1; - } - - if (nents < 0) { - printk("verify_maps: Error, messed up mappings, " - "at sg %d dma_sg %d\n", - (int) (orig_nents + nents), (int) (dma_sg - orig_dma_sg)); - return -1; - } - - /* This test passes... */ - return 0; -} - -void verify_sglist(struct scatterlist *sglist, int nents, iopte_t *iopte, int npages) -{ - struct scatterlist *sg; - - if (verify_lengths(sglist, nents, npages) < 0 || - verify_maps(sglist, nents, iopte) < 0) { - int i; - - printk("verify_sglist: Crap, messed up mappings, dumping, iodma at "); - printk("%016lx.\n", sglist->dma_address & IO_PAGE_MASK); - - for_each_sg(sglist, sg, nents, i) { - printk("sg(%d): page_addr(%p) off(%x) length(%x) " - "dma_address[%016x] dma_length[%016x]\n", - i, - page_address(sg_page(sg)), sg->offset, - sg->length, - sg->dma_address, sg->dma_length); - } - } - - /* Seems to be ok */ -} -#endif - -unsigned long prepare_sg(struct device *dev, struct scatterlist *sg, int nents) -{ - struct scatterlist *dma_sg = sg; - unsigned long prev; - u32 dent_addr, dent_len; - unsigned int max_seg_size; - - prev = (unsigned long) sg_virt(sg); - prev += (unsigned long) (dent_len = sg->length); - dent_addr = (u32) ((unsigned long)(sg_virt(sg)) & (IO_PAGE_SIZE - 1UL)); - max_seg_size = dma_get_max_seg_size(dev); - while (--nents) { - unsigned long addr; - - sg = sg_next(sg); - addr = (unsigned long) sg_virt(sg); - if (! VCONTIG(prev, addr) || - dent_len + sg->length > max_seg_size) { - dma_sg->dma_address = dent_addr; - dma_sg->dma_length = dent_len; - dma_sg = sg_next(dma_sg); - - dent_addr = ((dent_addr + - dent_len + - (IO_PAGE_SIZE - 1UL)) >> IO_PAGE_SHIFT); - dent_addr <<= IO_PAGE_SHIFT; - dent_addr += addr & (IO_PAGE_SIZE - 1UL); - dent_len = 0; - } - dent_len += sg->length; - prev = addr + sg->length; - } - dma_sg->dma_address = dent_addr; - dma_sg->dma_length = dent_len; - - if (dma_sg != sg) { - dma_sg = sg_next(dma_sg); - dma_sg->dma_length = 0; - } - - return ((unsigned long) dent_addr + - (unsigned long) dent_len + - (IO_PAGE_SIZE - 1UL)) >> IO_PAGE_SHIFT; -} diff --git a/arch/sparc64/kernel/iommu_common.h b/arch/sparc64/kernel/iommu_common.h index a90d046e8024..4b5cafa2877a 100644 --- a/arch/sparc64/kernel/iommu_common.h +++ b/arch/sparc64/kernel/iommu_common.h @@ -30,6 +30,32 @@ */ #define IOMMU_PAGE_SHIFT 13 +#define SG_ENT_PHYS_ADDRESS(SG) (__pa(sg_virt((SG)))) + +static inline unsigned long iommu_num_pages(unsigned long vaddr, + unsigned long slen) +{ + unsigned long npages; + + npages = IO_PAGE_ALIGN(vaddr + slen) - (vaddr & IO_PAGE_MASK); + npages >>= IO_PAGE_SHIFT; + + return npages; +} + +static inline unsigned long calc_npages(struct scatterlist *sglist, int nelems) +{ + unsigned long i, npages = 0; + struct scatterlist *sg; + + for_each_sg(sglist, sg, nelems, i) { + unsigned long paddr = SG_ENT_PHYS_ADDRESS(sg); + npages += iommu_num_pages(paddr, sg->length); + } + + return npages; +} + /* You are _strongly_ advised to enable the following debugging code * any time you make changes to the sg code below, run it for a while * with filesystems mounted read-only before buying the farm... -DaveM diff --git a/arch/sparc64/kernel/pci_sun4v.c b/arch/sparc64/kernel/pci_sun4v.c index 5ea2eab1ccda..61baf8dc095e 100644 --- a/arch/sparc64/kernel/pci_sun4v.c +++ b/arch/sparc64/kernel/pci_sun4v.c @@ -365,113 +365,14 @@ static void dma_4v_unmap_single(struct device *dev, dma_addr_t bus_addr, spin_unlock_irqrestore(&iommu->lock, flags); } -#define SG_ENT_PHYS_ADDRESS(SG) (__pa(sg_virt((SG)))) - -static long fill_sg(long entry, struct device *dev, - struct scatterlist *sg, - int nused, int nelems, unsigned long prot) -{ - struct scatterlist *dma_sg = sg; - unsigned long flags; - int i; - - local_irq_save(flags); - - iommu_batch_start(dev, prot, entry); - - for (i = 0; i < nused; i++) { - unsigned long pteval = ~0UL; - u32 dma_npages; - - dma_npages = ((dma_sg->dma_address & (IO_PAGE_SIZE - 1UL)) + - dma_sg->dma_length + - ((IO_PAGE_SIZE - 1UL))) >> IO_PAGE_SHIFT; - do { - unsigned long offset; - signed int len; - - /* If we are here, we know we have at least one - * more page to map. So walk forward until we - * hit a page crossing, and begin creating new - * mappings from that spot. - */ - for (;;) { - unsigned long tmp; - - tmp = SG_ENT_PHYS_ADDRESS(sg); - len = sg->length; - if (((tmp ^ pteval) >> IO_PAGE_SHIFT) != 0UL) { - pteval = tmp & IO_PAGE_MASK; - offset = tmp & (IO_PAGE_SIZE - 1UL); - break; - } - if (((tmp ^ (tmp + len - 1UL)) >> IO_PAGE_SHIFT) != 0UL) { - pteval = (tmp + IO_PAGE_SIZE) & IO_PAGE_MASK; - offset = 0UL; - len -= (IO_PAGE_SIZE - (tmp & (IO_PAGE_SIZE - 1UL))); - break; - } - sg = sg_next(sg); - nelems--; - } - - pteval = (pteval & IOPTE_PAGE); - while (len > 0) { - long err; - - err = iommu_batch_add(pteval); - if (unlikely(err < 0L)) - goto iommu_map_failed; - - pteval += IO_PAGE_SIZE; - len -= (IO_PAGE_SIZE - offset); - offset = 0; - dma_npages--; - } - - pteval = (pteval & IOPTE_PAGE) + len; - sg = sg_next(sg); - nelems--; - - /* Skip over any tail mappings we've fully mapped, - * adjusting pteval along the way. Stop when we - * detect a page crossing event. - */ - while (nelems && - (pteval << (64 - IO_PAGE_SHIFT)) != 0UL && - (pteval == SG_ENT_PHYS_ADDRESS(sg)) && - ((pteval ^ - (SG_ENT_PHYS_ADDRESS(sg) + sg->length - 1UL)) >> IO_PAGE_SHIFT) == 0UL) { - pteval += sg->length; - sg = sg_next(sg); - nelems--; - } - if ((pteval << (64 - IO_PAGE_SHIFT)) == 0UL) - pteval = ~0UL; - } while (dma_npages != 0); - dma_sg = sg_next(dma_sg); - } - - if (unlikely(iommu_batch_end() < 0L)) - goto iommu_map_failed; - - local_irq_restore(flags); - return 0; - -iommu_map_failed: - local_irq_restore(flags); - return -1L; -} - static int dma_4v_map_sg(struct device *dev, struct scatterlist *sglist, int nelems, enum dma_data_direction direction) { + unsigned long flags, npages, i, prot; + struct scatterlist *sg; struct iommu *iommu; - unsigned long flags, npages, prot; - u32 dma_base; - struct scatterlist *sgtmp; long entry, err; - int used; + u32 dma_base; /* Fast path single entry scatterlists. */ if (nelems == 1) { @@ -489,10 +390,8 @@ static int dma_4v_map_sg(struct device *dev, struct scatterlist *sglist, if (unlikely(direction == DMA_NONE)) goto bad; - /* Step 1: Prepare scatter list. */ - npages = prepare_sg(dev, sglist, nelems); + npages = calc_npages(sglist, nelems); - /* Step 2: Allocate a cluster and context, if necessary. */ spin_lock_irqsave(&iommu->lock, flags); entry = arena_alloc(&iommu->arena, npages); spin_unlock_irqrestore(&iommu->lock, flags); @@ -503,27 +402,45 @@ static int dma_4v_map_sg(struct device *dev, struct scatterlist *sglist, dma_base = iommu->page_table_map_base + (entry << IO_PAGE_SHIFT); - /* Step 3: Normalize DMA addresses. */ - used = nelems; - - sgtmp = sglist; - while (used && sgtmp->dma_length) { - sgtmp->dma_address += dma_base; - sgtmp = sg_next(sgtmp); - used--; - } - used = nelems - used; - - /* Step 4: Create the mappings. */ prot = HV_PCI_MAP_ATTR_READ; if (direction != DMA_TO_DEVICE) prot |= HV_PCI_MAP_ATTR_WRITE; - err = fill_sg(entry, dev, sglist, used, nelems, prot); + local_irq_save(flags); + + iommu_batch_start(dev, prot, entry); + + for_each_sg(sglist, sg, nelems, i) { + unsigned long paddr = SG_ENT_PHYS_ADDRESS(sg); + unsigned long slen = sg->length; + unsigned long this_npages; + + this_npages = iommu_num_pages(paddr, slen); + + sg->dma_address = dma_base | (paddr & ~IO_PAGE_MASK); + sg->dma_length = slen; + + paddr &= IO_PAGE_MASK; + while (this_npages--) { + err = iommu_batch_add(paddr); + if (unlikely(err < 0L)) { + local_irq_restore(flags); + goto iommu_map_failed; + } + + paddr += IO_PAGE_SIZE; + dma_base += IO_PAGE_SIZE; + } + } + + err = iommu_batch_end(); + + local_irq_restore(flags); + if (unlikely(err < 0L)) goto iommu_map_failed; - return used; + return nelems; bad: if (printk_ratelimit()) @@ -541,12 +458,11 @@ iommu_map_failed: static void dma_4v_unmap_sg(struct device *dev, struct scatterlist *sglist, int nelems, enum dma_data_direction direction) { + unsigned long flags, npages; struct pci_pbm_info *pbm; + u32 devhandle, bus_addr; struct iommu *iommu; - unsigned long flags, i, npages; - struct scatterlist *sg, *sgprv; long entry; - u32 devhandle, bus_addr; if (unlikely(direction == DMA_NONE)) { if (printk_ratelimit()) @@ -558,16 +474,8 @@ static void dma_4v_unmap_sg(struct device *dev, struct scatterlist *sglist, devhandle = pbm->devhandle; bus_addr = sglist->dma_address & IO_PAGE_MASK; - sgprv = NULL; - for_each_sg(sglist, sg, nelems, i) { - if (sg->dma_length == 0) - break; - - sgprv = sg; - } - npages = (IO_PAGE_ALIGN(sgprv->dma_address + sgprv->dma_length) - - bus_addr) >> IO_PAGE_SHIFT; + npages = calc_npages(sglist, nelems); entry = ((bus_addr - iommu->page_table_map_base) >> IO_PAGE_SHIFT); |