pstore: Introduce write_buf backend callback

For function tracing we need to stop using pstore.buf directly, since
in a tracing callback we can't use spinlocks, and thus we can't safely
use the global buffer.

With write_buf callback, backends no longer need to access pstore.buf
directly, and thus we can pass any buffers (e.g. allocated on stack).

Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/include/linux/pstore.h b/include/linux/pstore.h
index 1bd014b8e432..b107484192fc 100644
--- a/include/linux/pstore.h
+++ b/include/linux/pstore.h
@@ -48,6 +48,10 @@ struct pstore_info {
         int             (*write)(enum pstore_type_id type,
                         enum kmsg_dump_reason reason, u64 *id,
                         unsigned int part, size_t size, struct pstore_info *psi);
+        int             (*write_buf)(enum pstore_type_id type,
+                        enum kmsg_dump_reason reason, u64 *id,
+                        unsigned int part, const char *buf, size_t size,
+                        struct pstore_info *psi);
         int             (*erase)(enum pstore_type_id type, u64 id,
                         struct pstore_info *psi);
         void            *data;