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Subject[PATCH 03/10] drbd: Introduce drbd_header_size()
Date
From: Andreas Gruenbacher <agruen@linbit.com>

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
---
drivers/block/drbd/drbd_int.h | 2 ++
drivers/block/drbd/drbd_main.c | 14 ++++++++++++++
drivers/block/drbd/drbd_receiver.c | 9 +++++----
3 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index d61819f..29db016 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -315,6 +315,8 @@ struct p_header {
u8 payload[0];
};

+extern unsigned int drbd_header_size(struct drbd_tconn *tconn);
+
/*
* short commands, packets without payload, plain p_header:
* P_PING
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index c8384cd..b291d73 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -689,6 +689,20 @@ void drbd_thread_current_set_cpu(struct drbd_thread *thi)
}
#endif

+/**
+ * drbd_header_size - size of a packet header
+ *
+ * The header size is a multiple of 8, so any payload following the header is
+ * word aligned on 64-bit architectures. (The bitmap send and receive code
+ * relies on this.)
+ */
+unsigned int drbd_header_size(struct drbd_tconn *tconn)
+{
+ BUILD_BUG_ON(sizeof(struct p_header80) != sizeof(struct p_header95));
+ BUILD_BUG_ON(!IS_ALIGNED(sizeof(struct p_header80), 8));
+ return sizeof(struct p_header80);
+}
+
static void prepare_header80(struct p_header80 *h, enum drbd_packet cmd, int size)
{
h->magic = cpu_to_be32(DRBD_MAGIC);
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 6879082..ceca24f 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -998,7 +998,7 @@ static int drbd_recv_header(struct drbd_tconn *tconn, struct packet_info *pi)
struct p_header *h = tconn->data.rbuf;
int err;

- err = drbd_recv_all_warn(tconn, h, sizeof(*h));
+ err = drbd_recv_all_warn(tconn, h, drbd_header_size(tconn));
if (err)
return err;

@@ -4845,7 +4845,8 @@ int drbd_asender(struct drbd_thread *thi)
int rv;
void *buf = h;
int received = 0;
- int expect = sizeof(struct p_header);
+ unsigned int header_size = drbd_header_size(tconn);
+ int expect = header_size;
int ping_timeout_active = 0;

current->policy = SCHED_RR; /* Make this a realtime task! */
@@ -4929,7 +4930,7 @@ int drbd_asender(struct drbd_thread *thi)
goto disconnect;
}
expect = cmd->pkt_size;
- if (pi.size != expect - sizeof(struct p_header)) {
+ if (pi.size != expect - header_size) {
conn_err(tconn, "Wrong packet size on meta (c: %d, l: %d)\n",
pi.cmd, pi.size);
goto reconnect;
@@ -4953,7 +4954,7 @@ int drbd_asender(struct drbd_thread *thi)

buf = h;
received = 0;
- expect = sizeof(struct p_header);
+ expect = header_size;
cmd = NULL;
}
}
--
1.7.4.1


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