From: Richard Zidlicky <rz@linux-m68k.org> To: Jiri Slaby <jirislaby@gmail.com> Cc: Kulikov Vasiliy <segooon@gmail.com>, kernel-janitors@vger.kernel.org, Mauro Carvalho Chehab <mchehab@infradead.org>, Douglas Schilling Landgraf <dougsland@redhat.com>, Jiri Kosina <jkosina@suse.cz>, Roel Kluin <roel.kluin@gmail.com>, Andrew Morton <akpm@linux-foundation.org>, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] dvb: siano: free spinlock before schedule() Date: Sun, 8 Aug 2010 18:10:22 +0200 [thread overview] Message-ID: <20100808161022.GB5594@linux-m68k.org> (raw) In-Reply-To: <4C4F5CA7.1030706@gmail.com> On Wed, Jul 28, 2010 at 12:24:39AM +0200, Jiri Slaby wrote: sorry for seeing this so late, was flooded with email lately. > There is a better fix (which fixes the potential NULL dereference): > http://lkml.org/lkml/2010/6/7/175 > Richard, could you address the comments there and resend? I am running this patch since many weeks (after fixing the compile error obviously). Did not implement your beautification suggestion yet, was doing all kinds of experiments with IR and had plenty of unrelated issues. Richard --- linux-2.6.34/drivers/media/dvb/siano/smscoreapi.c.rz 2010-06-03 21:58:11.000000000 +0200 +++ linux-2.6.34/drivers/media/dvb/siano/smscoreapi.c 2010-06-07 14:32:06.000000000 +0200 @@ -1100,31 +1100,26 @@ * * @return pointer to descriptor on success, NULL on error. */ -struct smscore_buffer_t *smscore_getbuffer(struct smscore_device_t *coredev) + +struct smscore_buffer_t *get_entry(struct smscore_device_t *coredev) { struct smscore_buffer_t *cb = NULL; unsigned long flags; - DEFINE_WAIT(wait); - spin_lock_irqsave(&coredev->bufferslock, flags); - - /* This function must return a valid buffer, since the buffer list is - * finite, we check that there is an available buffer, if not, we wait - * until such buffer become available. - */ - - prepare_to_wait(&coredev->buffer_mng_waitq, &wait, TASK_INTERRUPTIBLE); - - if (list_empty(&coredev->buffers)) - schedule(); - - finish_wait(&coredev->buffer_mng_waitq, &wait); - + if (!list_empty(&coredev->buffers)) { cb = (struct smscore_buffer_t *) coredev->buffers.next; list_del(&cb->entry); - + } spin_unlock_irqrestore(&coredev->bufferslock, flags); + return cb; +} + +struct smscore_buffer_t *smscore_getbuffer(struct smscore_device_t *coredev) +{ + struct smscore_buffer_t *cb = NULL; + + wait_event(coredev->buffer_mng_waitq, (cb = get_entry(coredev))); return cb; }
WARNING: multiple messages have this Message-ID (diff)
From: Richard Zidlicky <rz@linux-m68k.org> To: Jiri Slaby <jirislaby@gmail.com> Cc: Kulikov Vasiliy <segooon@gmail.com>, kernel-janitors@vger.kernel.org, Mauro Carvalho Chehab <mchehab@infradead.org>, Douglas Schilling Landgraf <dougsland@redhat.com>, Jiri Kosina <jkosina@suse.cz>, Roel Kluin <roel.kluin@gmail.com>, Andrew Morton <akpm@linux-foundation.org>, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] dvb: siano: free spinlock before schedule() Date: Sun, 08 Aug 2010 16:10:22 +0000 [thread overview] Message-ID: <20100808161022.GB5594@linux-m68k.org> (raw) In-Reply-To: <4C4F5CA7.1030706@gmail.com> On Wed, Jul 28, 2010 at 12:24:39AM +0200, Jiri Slaby wrote: sorry for seeing this so late, was flooded with email lately. > There is a better fix (which fixes the potential NULL dereference): > http://lkml.org/lkml/2010/6/7/175 > Richard, could you address the comments there and resend? I am running this patch since many weeks (after fixing the compile error obviously). Did not implement your beautification suggestion yet, was doing all kinds of experiments with IR and had plenty of unrelated issues. Richard --- linux-2.6.34/drivers/media/dvb/siano/smscoreapi.c.rz 2010-06-03 21:58:11.000000000 +0200 +++ linux-2.6.34/drivers/media/dvb/siano/smscoreapi.c 2010-06-07 14:32:06.000000000 +0200 @@ -1100,31 +1100,26 @@ * * @return pointer to descriptor on success, NULL on error. */ -struct smscore_buffer_t *smscore_getbuffer(struct smscore_device_t *coredev) + +struct smscore_buffer_t *get_entry(struct smscore_device_t *coredev) { struct smscore_buffer_t *cb = NULL; unsigned long flags; - DEFINE_WAIT(wait); - spin_lock_irqsave(&coredev->bufferslock, flags); - - /* This function must return a valid buffer, since the buffer list is - * finite, we check that there is an available buffer, if not, we wait - * until such buffer become available. - */ - - prepare_to_wait(&coredev->buffer_mng_waitq, &wait, TASK_INTERRUPTIBLE); - - if (list_empty(&coredev->buffers)) - schedule(); - - finish_wait(&coredev->buffer_mng_waitq, &wait); - + if (!list_empty(&coredev->buffers)) { cb = (struct smscore_buffer_t *) coredev->buffers.next; list_del(&cb->entry); - + } spin_unlock_irqrestore(&coredev->bufferslock, flags); + return cb; +} + +struct smscore_buffer_t *smscore_getbuffer(struct smscore_device_t *coredev) +{ + struct smscore_buffer_t *cb = NULL; + + wait_event(coredev->buffer_mng_waitq, (cb = get_entry(coredev))); return cb; }
next prev parent reply other threads:[~2010-08-08 16:16 UTC|newest] Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top 2010-07-27 18:42 [PATCH] dvb: siano: free spinlock before schedule() Kulikov Vasiliy 2010-07-27 18:42 ` Kulikov Vasiliy 2010-07-27 22:24 ` Jiri Slaby 2010-07-27 22:24 ` Jiri Slaby 2010-08-08 16:10 ` Richard Zidlicky [this message] 2010-08-08 16:10 ` Richard Zidlicky 2010-08-24 12:52 ` Mauro Carvalho Chehab 2010-08-24 12:52 ` Mauro Carvalho Chehab 2010-08-24 15:43 ` Richard Zidlicky 2010-08-24 15:43 ` Richard Zidlicky
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