Registering a zero length buffer is meaningless so check this at
ib_umem_get() and return immediately with error if that is the case.
If we don't do this, we get an inconsistent behaviour. For example,
if we register a buffer whose start address is not page aligned, we
will end up registering one page, while if the address is page
aligned, we will have zero pages -- the reason for this comes from
the following statement:
npages = PAGE_ALIGN(size + umem->offset) >> PAGE_SHIFT;
Problem found by: Ronni Zimmermann <[EMAIL PROTECTED]>
Signed-off-by: Eli Cohen <[EMAIL PROTECTED]>
---
drivers/infiniband/core/umem.c | 3 +++
1 files changed, 3 insertions(+), 0 deletions(-)
diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c
index 6f7c096..2541ef8 100644
--- a/drivers/infiniband/core/umem.c
+++ b/drivers/infiniband/core/umem.c
@@ -89,6 +89,9 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context,
unsigned long addr,
int i;
DEFINE_DMA_ATTRS(attrs);
+ if (!size)
+ return ERR_PTR(-ENOMEM);
+
if (dmasync)
dma_set_attr(DMA_ATTR_WRITE_BARRIER, &attrs);
--
1.5.6
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