bcon: make console_bytes atomic64_t
u64 has no alignment guarantees and given the layout of the structure
there was a 50/50 chance of console_bytes being aligned or not,
depending on config options. Was caught by Fengguang Wu's build bot,
due to a build failure on avr32.
Signed-off-by: Joern Engel <joern@logfs.org>
diff --git a/drivers/block/blockconsole.c b/drivers/block/blockconsole.c
index 65f8ace..c478e00 100644
--- a/drivers/block/blockconsole.c
+++ b/drivers/block/blockconsole.c
@@ -49,11 +49,11 @@
struct blockconsole {
char devname[32];
+ atomic64_t console_bytes;
spinlock_t end_io_lock;
struct timer_list pad_timer;
int error_count;
struct kref kref;
- u64 console_bytes;
u64 write_bytes;
u64 max_bytes;
u32 round;
@@ -107,7 +107,7 @@
static int bcon_console_ofs(struct blockconsole *bc)
{
- return __bcon_console_ofs(bc->console_bytes);
+ return __bcon_console_ofs(atomic64_read(&bc->console_bytes));
}
static int __bcon_console_sector(u64 console_bytes)
@@ -117,7 +117,7 @@
static int bcon_console_sector(struct blockconsole *bc)
{
- return __bcon_console_sector(bc->console_bytes);
+ return __bcon_console_sector(atomic64_read(&bc->console_bytes));
}
static int bcon_write_sector(struct blockconsole *bc)
@@ -135,7 +135,7 @@
{
char *buf = page_address(bc->pages);
size_t len = strlen(BLOCKCONSOLE_MAGIC);
- u32 tile = bc->console_bytes >> 20; /* We overflow after 4TB - fine */
+ u32 tile = atomic64_read(&bc->console_bytes) >> 20; /* We overflow after 4TB - fine */
clear_sector(buf);
memcpy(buf, BLOCKCONSOLE_MAGIC, len);
@@ -153,7 +153,7 @@
u64 old, new;
do {
- old = bc->console_bytes;
+ old = atomic64_read(&bc->console_bytes);
new = old + bytes;
if (new >= bc->max_bytes)
new = 0;
@@ -161,7 +161,7 @@
bcon_init_first_page(bc);
new += BCON_LONG_HEADERSIZE;
}
- } while (cmpxchg64(&bc->console_bytes, old, new) != old);
+ } while (atomic64_cmpxchg(&bc->console_bytes, old, new) != old);
}
static void request_complete(struct bio *bio, int err)
@@ -268,7 +268,8 @@
start = middle;
}
}
- bc->console_bytes = bc->write_bytes = end;
+ bc->write_bytes = end;
+ atomic64_set(&bc->console_bytes, end);
bcon_advance_console_bytes(bc, 0); /* To skip the header */
bcon_advance_write_bytes(bc, 0); /* To wrap around, if necessary */
bcon_erase_segment(bc);
@@ -399,7 +400,7 @@
int i;
while (len) {
- console_bytes = bc->console_bytes;
+ console_bytes = atomic64_read(&bc->console_bytes);
i = __bcon_console_sector(console_bytes);
rmb();
if (bc->bio_array[i].in_flight)
@@ -515,8 +516,8 @@
bc->panic_block.notifier_call = blockconsole_panic;
bc->panic_block.priority = INT_MAX;
atomic_notifier_chain_register(&panic_notifier_list, &bc->panic_block);
- pr_info("now logging to %s at %llx\n", devname, bc->console_bytes >> 20);
-
+ pr_info("now logging to %s at %llx\n", devname,
+ atomic64_read(&bc->console_bytes) >> 20);
return 0;
out2:
