iommu sg merging: x86: make pci-gart iommu respect the segment size limits

This patch makes pci-gart 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: Dave Airlie <airlied@linux.ie>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/x86/kernel/pci-gart_64.c b/arch/x86/kernel/pci-gart_64.c
index 845cbecd68e963ae3063ef56f9d27d91c9238c69..5ee700f0844de67675bae79b8138ffdcf6131a94 100644 (file)
--- a/arch/x86/kernel/pci-gart_64.c
+++ b/arch/x86/kernel/pci-gart_64.c
@@ -416,6 +416,8 @@ gart_map_sg(struct device *dev, struct scatterlist *sg, int nents, int dir)
        struct scatterlist *s, *ps, *start_sg, *sgmap;
        int need = 0, nextneed, i, out, start;
        unsigned long pages = 0;
+       unsigned int seg_size;
+       unsigned int max_seg_size;
 
        if (nents == 0)
                return 0;
@@ -426,6 +428,8 @@ gart_map_sg(struct device *dev, struct scatterlist *sg, int nents, int dir)
        out = 0;
        start = 0;
        start_sg = sgmap = sg;
+       seg_size = 0;
+       max_seg_size = dma_get_max_seg_size(dev);
        ps = NULL; /* shut up gcc */
        for_each_sg(sg, s, nents, i) {
                dma_addr_t addr = sg_phys(s);
@@ -443,11 +447,13 @@ gart_map_sg(struct device *dev, struct scatterlist *sg, int nents, int dir)
                         * offset.
                         */
                        if (!iommu_merge || !nextneed || !need || s->offset ||
+                           (s->length + seg_size > max_seg_size) ||
                            (ps->offset + ps->length) % PAGE_SIZE) {
                                if (dma_map_cont(start_sg, i - start, sgmap,
                                                  pages, need) < 0)
                                        goto error;
                                out++;
+                               seg_size = 0;
                                sgmap = sg_next(sgmap);
                                pages = 0;
                                start = i;
@@ -455,6 +461,7 @@ gart_map_sg(struct device *dev, struct scatterlist *sg, int nents, int dir)
                        }
                }
 
+               seg_size += s->length;
                need = nextneed;
                pages += to_pages(s->offset, s->length);
                ps = s;