In some drivers there's a need to read data from a user space area that
was pinned using ib_umem, when running from a different process context.
The ib_umem_copy_from function allows reading data from the physical pages
pinned in the ib_umem struct.
Signed-off-by: Haggai Eran <hagg...@mellanox.com>
---
drivers/infiniband/core/umem.c | 25 +++++++++++++++++++++++++
include/rdma/ib_umem.h | 2 ++
2 files changed, 27 insertions(+)
diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c
index ab14b33..138442a 100644
--- a/drivers/infiniband/core/umem.c
+++ b/drivers/infiniband/core/umem.c
@@ -287,3 +287,28 @@ int ib_umem_page_count(struct ib_umem *umem)
return n;
}
EXPORT_SYMBOL(ib_umem_page_count);
+
+/*
+ * Copy from the given ib_umem's pages to the given buffer.
+ *
+ * umem - the umem to copy from
+ * start - offset to start copying from
+ * dst - destination buffer
+ * length - buffer length
+ *
+ * Returns the number of copied bytes, or an error code.
+ */
+int ib_umem_copy_from(struct ib_umem *umem, size_t start, void *dst,
+ size_t length)
+{
+ size_t end = start + length;
+
+ if (start > umem->length || end > umem->length || end < start) {
+ pr_err("ib_umem_copy_from not in range.");
+ return -EINVAL;
+ }
+
+ return sg_pcopy_to_buffer(umem->sg_head.sgl, umem->nmap, dst, length,
+ start + ib_umem_offset(umem));
+}
+EXPORT_SYMBOL(ib_umem_copy_from);
diff --git a/include/rdma/ib_umem.h b/include/rdma/ib_umem.h
index 0e120f4..6af91b3 100644
--- a/include/rdma/ib_umem.h
+++ b/include/rdma/ib_umem.h
@@ -83,6 +83,8 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context,
unsigned long addr,
size_t size, int access, int dmasync);
void ib_umem_release(struct ib_umem *umem);
int ib_umem_page_count(struct ib_umem *umem);
+int ib_umem_copy_from(struct ib_umem *umem, size_t start, void *dst,
+ size_t length);
#else /* CONFIG_INFINIBAND_USER_MEM */
--
1.7.11.2
--
To unsubscribe from this list: send the line "unsubscribe linux-rdma" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
