Hi Davidlohr, Am 01.11.19 um 19:29 schrieb Davidlohr Bueso: > There is no need to be using a semaphore, or a sleeping lock > in the first place: critical region is extremely short, does not > call into any blocking calls and furthermore lock and unlocking > operations occur in the same context. > > Get rid of another semaphore user by replacing it with a spinlock. > > Signed-off-by: Davidlohr Bueso <dave@xxxxxxxxxxxx> > --- > This is in an effort to further reduce semaphore users in the kernel. > > This is a resend, which just seems simpler given the confusions. > > .../staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c | 10 +++++----- > 1 file changed, 5 insertions(+), 5 deletions(-) > > diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c > index 8dc730cfe7a6..710d21654128 100644 > --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c > +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c > @@ -63,7 +63,7 @@ static char *g_free_fragments; > static struct semaphore g_free_fragments_sema; > static struct device *g_dev; > > -static DEFINE_SEMAPHORE(g_free_fragments_mutex); > +static DEFINE_SPINLOCK(g_free_fragments_lock); > > static irqreturn_t > vchiq_doorbell_irq(int irq, void *dev_id); > @@ -528,11 +528,11 @@ create_pagelist(char __user *buf, size_t count, unsigned short type) > > WARN_ON(g_free_fragments == NULL); > > - down(&g_free_fragments_mutex); > + spin_lock(&g_free_fragments_lock); > fragments = g_free_fragments; > WARN_ON(fragments == NULL); > g_free_fragments = *(char **) g_free_fragments; > - up(&g_free_fragments_mutex); > + spin_unlock(&g_free_fragments_lock); > the reason why Greg cannot apply this patch is that you are using an old or the wrong git tree. Please make sure you use the following one (or a mirror): https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git and operate on the branch staging-next Please fix this up and send a new version. Regards Stefan _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
