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