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authorSebastian Andrzej Siewior <sebastian@breakpoint.cc>2009-06-18 10:19:12 +0200
committerPierre Ossman <pierre@ossman.eu>2009-07-31 12:28:45 +0200
commit6de7e356faf54aa75de5b624bbce28a5b776dfa8 (patch)
tree09b341b7c1371448a5ae8a9cd4009a4f81f4a3dd /lib/scatterlist.c
parentb592972493c38665efd7d429a01b23fcb21e331a (diff)
downloadlinux-linaro-stable-6de7e356faf54aa75de5b624bbce28a5b776dfa8.tar.gz
lib/scatterlist: add a flags to signalize mapping direction
sg_miter_start() is currently unaware of the direction of the copy process (to or from the scatter list). It is important to know the direction because the page has to be flushed in case the data written is seen on a different mapping in user land on cache incoherent architectures. Signed-off-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc> Acked-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Pierre Ossman <pierre@ossman.eu>
Diffstat (limited to 'lib/scatterlist.c')
-rw-r--r--lib/scatterlist.c16
1 files changed, 12 insertions, 4 deletions
diff --git a/lib/scatterlist.c b/lib/scatterlist.c
index a295e404e908..0d475d8167bf 100644
--- a/lib/scatterlist.c
+++ b/lib/scatterlist.c
@@ -314,6 +314,7 @@ void sg_miter_start(struct sg_mapping_iter *miter, struct scatterlist *sgl,
miter->__sg = sgl;
miter->__nents = nents;
miter->__offset = 0;
+ WARN_ON(!(flags & (SG_MITER_TO_SG | SG_MITER_FROM_SG)));
miter->__flags = flags;
}
EXPORT_SYMBOL(sg_miter_start);
@@ -394,6 +395,9 @@ void sg_miter_stop(struct sg_mapping_iter *miter)
if (miter->addr) {
miter->__offset += miter->consumed;
+ if (miter->__flags & SG_MITER_TO_SG)
+ flush_kernel_dcache_page(miter->page);
+
if (miter->__flags & SG_MITER_ATOMIC) {
WARN_ON(!irqs_disabled());
kunmap_atomic(miter->addr, KM_BIO_SRC_IRQ);
@@ -426,8 +430,14 @@ static size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents,
unsigned int offset = 0;
struct sg_mapping_iter miter;
unsigned long flags;
+ unsigned int sg_flags = SG_MITER_ATOMIC;
+
+ if (to_buffer)
+ sg_flags |= SG_MITER_FROM_SG;
+ else
+ sg_flags |= SG_MITER_TO_SG;
- sg_miter_start(&miter, sgl, nents, SG_MITER_ATOMIC);
+ sg_miter_start(&miter, sgl, nents, sg_flags);
local_irq_save(flags);
@@ -438,10 +448,8 @@ static size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents,
if (to_buffer)
memcpy(buf + offset, miter.addr, len);
- else {
+ else
memcpy(miter.addr, buf + offset, len);
- flush_kernel_dcache_page(miter.page);
- }
offset += len;
}