The patch titled
Subject: w1: introduce a slave mutex for serializing IO
has been added to the -mm tree. Its filename is
w1-introduce-a-slave-mutex-for-serializing-io.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: NeilBrown <neilb@xxxxxxx>
Subject: w1: introduce a slave mutex for serializing IO
w1 devices need a mutex to serial IO. Most use master->mutex.
However that is used for other purposes and they can conflict.
In particular master->mutex is held while w1_attach_slave_device is
called.
For bq27000, this registers a 'powersupply' device which tries to read the
current status. The attempt to read will cause a deadlock on
master->mutex.
So create a new per-slave mutex and use that for serializing IO for
bq27000.
Signed-off-by: NeilBrown <neilb@xxxxxxx>
Cc: Evgeniy Polyakov <zbr@xxxxxxxxxxx>
Cc: Greg KH <greg@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/w1/slaves/w1_bq27000.c | 4 ++--
drivers/w1/w1.c | 1 +
drivers/w1/w1.h | 1 +
3 files changed, 4 insertions(+), 2 deletions(-)
diff -puN drivers/w1/slaves/w1_bq27000.c~w1-introduce-a-slave-mutex-for-serializing-io drivers/w1/slaves/w1_bq27000.c
--- a/drivers/w1/slaves/w1_bq27000.c~w1-introduce-a-slave-mutex-for-serializing-io
+++ a/drivers/w1/slaves/w1_bq27000.c
@@ -31,10 +31,10 @@ static int w1_bq27000_read(struct device
u8 val;
struct w1_slave *sl = container_of(dev->parent, struct w1_slave, dev);
- mutex_lock(&sl->master->mutex);
+ mutex_lock(&sl->mutex);
w1_write_8(sl->master, HDQ_CMD_READ | reg);
val = w1_read_8(sl->master);
- mutex_unlock(&sl->master->mutex);
+ mutex_unlock(&sl->mutex);
return val;
}
diff -puN drivers/w1/w1.c~w1-introduce-a-slave-mutex-for-serializing-io drivers/w1/w1.c
--- a/drivers/w1/w1.c~w1-introduce-a-slave-mutex-for-serializing-io
+++ a/drivers/w1/w1.c
@@ -688,6 +688,7 @@ static int w1_attach_slave_device(struct
memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
atomic_set(&sl->refcnt, 0);
init_completion(&sl->released);
+ mutex_init(&sl->mutex);
spin_lock(&w1_flock);
f = w1_family_registered(rn->family);
diff -puN drivers/w1/w1.h~w1-introduce-a-slave-mutex-for-serializing-io drivers/w1/w1.h
--- a/drivers/w1/w1.h~w1-introduce-a-slave-mutex-for-serializing-io
+++ a/drivers/w1/w1.h
@@ -75,6 +75,7 @@ struct w1_slave
void *family_data;
struct device dev;
struct completion released;
+ struct mutex mutex;
};
typedef void (*w1_slave_found_callback)(struct w1_master *, u64);
_
Subject: Subject: w1: introduce a slave mutex for serializing IO
Patches currently in -mm which might be from neilb@xxxxxxx are
linux-next.patch
umem-fix-up-unplugging.patch
leds-add-new-transient-trigger-for-one-shot-timer-activation.patch
w1-introduce-a-slave-mutex-for-serializing-io.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
