iommu sg merging: ppc: make iommu respect the segment size limits

This patch makes iommu respect segment size limits when merging sg
lists.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/powerpc/kernel/dma_64.c b/arch/powerpc/kernel/dma_64.c
index 84239076a5b8e8092e7ad2d607ba16b0e0cff7a9..f9de2fddf4d602723ac6346fde9e14e0771e9b46 100644 (file)
--- a/arch/powerpc/kernel/dma_64.c
+++ b/arch/powerpc/kernel/dma_64.c
@@ -68,7 +68,7 @@ static void dma_iommu_unmap_single(struct device *dev, dma_addr_t dma_handle,
 static int dma_iommu_map_sg(struct device *dev, struct scatterlist *sglist,
                            int nelems, enum dma_data_direction direction)
 {
-       return iommu_map_sg(dev->archdata.dma_data, sglist, nelems,
+       return iommu_map_sg(dev, sglist, nelems,
                            device_to_mask(dev), direction);
 }
 

diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index a3c406aca6643d04ed6a7351086bfa0d1a4b2738..d0e6fac4ef42bd63eaba13f66112aa3ae8bfa87c 100644 (file)
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -270,16 +270,18 @@ static void iommu_free(struct iommu_table *tbl, dma_addr_t dma_addr,
        spin_unlock_irqrestore(&(tbl->it_lock), flags);
 }
 
-int iommu_map_sg(struct iommu_table *tbl, struct scatterlist *sglist,
+int iommu_map_sg(struct device *dev, struct scatterlist *sglist,
                 int nelems, unsigned long mask,
                 enum dma_data_direction direction)
 {
+       struct iommu_table *tbl = dev->archdata.dma_data;
        dma_addr_t dma_next = 0, dma_addr;
        unsigned long flags;
        struct scatterlist *s, *outs, *segstart;
        int outcount, incount, i;
        unsigned int align;
        unsigned long handle;
+       unsigned int max_seg_size;
 
        BUG_ON(direction == DMA_NONE);
 
@@ -298,6 +300,7 @@ int iommu_map_sg(struct iommu_table *tbl, struct scatterlist *sglist,
 
        spin_lock_irqsave(&(tbl->it_lock), flags);
 
+       max_seg_size = dma_get_max_seg_size(dev);
        for_each_sg(sglist, s, nelems, i) {
                unsigned long vaddr, npages, entry, slen;
 
@@ -344,7 +347,8 @@ int iommu_map_sg(struct iommu_table *tbl, struct scatterlist *sglist,
                        /* We cannot merge if:
                         * - allocated dma_addr isn't contiguous to previous allocation
                         */
-                       if (novmerge || (dma_addr != dma_next)) {
+                       if (novmerge || (dma_addr != dma_next) ||
+                           (outs->dma_length + s->length > max_seg_size)) {
                                /* Can't merge: create a new segment */
                                segstart = s;
                                outcount++;

diff --git a/include/asm-powerpc/iommu.h b/include/asm-powerpc/iommu.h
index 7a3cef785abdee2aa52b2cdc6716bdf04348b291..a07a67c80c1f616f29550d363853a219f8c72008 100644 (file)
--- a/include/asm-powerpc/iommu.h
+++ b/include/asm-powerpc/iommu.h
@@ -79,7 +79,7 @@ extern void iommu_free_table(struct iommu_table *tbl, const char *node_name);
 extern struct iommu_table *iommu_init_table(struct iommu_table * tbl,
                                            int nid);
 
-extern int iommu_map_sg(struct iommu_table *tbl, struct scatterlist *sglist,
+extern int iommu_map_sg(struct device *dev, struct scatterlist *sglist,
                        int nelems, unsigned long mask,
                        enum dma_data_direction direction);
 extern void iommu_unmap_sg(struct iommu_table *tbl, struct scatterlist *sglist,