Hi, >-----Original Message----- >From: Hiroshi DOYU [mailto:Hiroshi.DOYU@xxxxxxxxx] >Sent: Monday, February 15, 2010 7:49 AM >To: Guzman Lugo, Fernando >Cc: linux-omap@xxxxxxxxxxxxxxx >Subject: Re: [PATCH 5/6] Mailbox: sleeping function called from invalid >context fix > >Hi Fernando, > >From: "ext Guzman Lugo, Fernando" <x0095840@xxxxxx> >Subject: [PATCH 5/6] Mailbox: sleeping function called from invalid context >fix >Date: Sat, 13 Feb 2010 02:42:16 +0100 > >> From e06b2716824f225747c4dc83ed2623d0160ae132 Mon Sep 17 00:00:00 2001 >> From: Fernando Guzman Lugo <x0095840@xxxxxx> >> Date: Fri, 29 Jan 2010 17:12:24 -0600 >> Subject: [PATCH] Mailbox: sleeping function called from invalid context >fix >> >> This patch fixes this bug: >> BUG: sleeping function called from invalid context >> Inside omap2_mbox_startup is called clk_get_sys that can sleep, >> therefore omap2_mbox_startup can sleep but it is call in an atomic >> context . So the spinlock is change for a semaphore. > >"mboxes_lock" is used to maintain the global list of mailbox >instances, which belong to a single mailbox H/W module, but they are >logical channels from S/W perspective. Both "->ops->startup()" and >"->ops->shutdown()" are being executed against the above single H/W >module, and a mailbox H/W module is totally __independent__ of the >registration of logical mailboxes, which are (un)registered with Yes, they are independent of each other, and can be executed at the same time. I am agreed with your patch; that should be the right solution, so you can drop my patch. Thanks and regards, Fernando. >"omap_mbox_(un)register()". IOW, a mbox instance can be registered at >anytime(before/after) H/W initialization. This H/W initialization is >taken care of by "mbox_configured" variable. So I might think that the >right solution is to introduce a new mutex lock __just for__ h/w >configuration as below: > > Modified arch/arm/plat-omap/mailbox.c >diff --git a/arch/arm/plat-omap/mailbox.c b/arch/arm/plat-omap/mailbox.c >index 8e90633..19530de 100644 >--- a/arch/arm/plat-omap/mailbox.c >+++ b/arch/arm/plat-omap/mailbox.c >@@ -32,6 +32,7 @@ static struct omap_mbox *mboxes; > static DEFINE_RWLOCK(mboxes_lock); > > static int mbox_configured; >+static DEFINE_MUTEX(mbox_configured_lock); > > /* Mailbox FIFO handle functions */ > static inline mbox_msg_t mbox_fifo_read(struct omap_mbox *mbox) >@@ -247,16 +248,16 @@ static int omap_mbox_startup(struct omap_mbox *mbox) > struct omap_mbox_queue *mq; > > if (likely(mbox->ops->startup)) { >- write_lock(&mboxes_lock); >+ mutex_lock(&mbox_configured_lock); > if (!mbox_configured) > ret = mbox->ops->startup(mbox); > > if (unlikely(ret)) { >- write_unlock(&mboxes_lock); >+ mutex_unlock(&mbox_configured_lock); > return ret; > } > mbox_configured++; >- write_unlock(&mboxes_lock); >+ mutex_unlock(&mbox_configured_lock); > } > > ret = request_irq(mbox->irq, mbox_interrupt, IRQF_SHARED, >@@ -302,12 +303,12 @@ static void omap_mbox_fini(struct omap_mbox *mbox) > free_irq(mbox->irq, mbox); > > if (unlikely(mbox->ops->shutdown)) { >- write_lock(&mboxes_lock); >+ mutex_lock(&mbox_configured_lock); > if (mbox_configured > 0) > mbox_configured--; > if (!mbox_configured) > mbox->ops->shutdown(mbox); >- write_unlock(&mboxes_lock); >+ mutex_unlock(&mbox_configured_lock); > } > } -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
