> -----Original Message----- > From: Ira W. Snyder [mailto:iws@xxxxxxxxxxxxxxxx] > Sent: Thursday, August 02, 2012 1:31 AM > To: Liu Qiang-B32616 > Cc: linux-crypto@xxxxxxxxxxxxxxx; linuxppc-dev@xxxxxxxxxxxxxxxx; linux- > kernel@xxxxxxxxxxxxxxx; dan.j.williams@xxxxxxxxx; Vinod Koul; Tabi Timur- > B04825; herbert@xxxxxxxxxxxxxxxxxxxx; Dan Williams; davem@xxxxxxxxxxxxx > Subject: Re: [PATCH v5 5/6] fsl-dma: use spin_lock_bh to instead of > spin_lock_irqsave > > On Wed, Aug 01, 2012 at 04:50:09PM +0800, qiang.liu@xxxxxxxxxxxxx wrote: > > From: Qiang Liu <qiang.liu@xxxxxxxxxxxxx> > > > > - use spin_lock_bh() is the right way to use async_tx api, > > dma_run_dependencies() should not be protected by spin_lock_irqsave(); > > - use spin_lock_bh to instead of spin_lock_irqsave for improving > > performance, There is not any place to access descriptor queues in > > fsl-dma ISR except its tasklet, spin_lock_bh() is more proper here. > > Interrupts will be turned off and context will be save in irqsave, > there is needless to use irqsave.. > > > > This description is not very clear English. I understand it is not your > native language. Let me try to help. > > """ > The use of spin_lock_irqsave() is a stronger locking mechanism than is > required throughout the driver. The minimum locking required should be > used instead. > > Change all instances of spin_lock_irqsave() to spin_lock_bh(). All > manipulation of protected fields is done using tasklet context or weaker, > which makes spin_lock_bh() the correct choice. > """ I will modify the description in v6, please check later. > > Other than that, > Acked-by: Ira W. Snyder <iws@xxxxxxxxxxxxxxxx> Thanks. > > > Cc: Dan Williams <dan.j.williams@xxxxxxxxx> > > Cc: Vinod Koul <vinod.koul@xxxxxxxxx> > > Cc: Li Yang <leoli@xxxxxxxxxxxxx> > > Cc: Timur Tabi <timur@xxxxxxxxxxxxx> > > Signed-off-by: Qiang Liu <qiang.liu@xxxxxxxxxxxxx> > > --- > > drivers/dma/fsldma.c | 30 ++++++++++++------------------ > > 1 files changed, 12 insertions(+), 18 deletions(-) > > > > diff --git a/drivers/dma/fsldma.c b/drivers/dma/fsldma.c index > > bb883c0..e3814aa 100644 > > --- a/drivers/dma/fsldma.c > > +++ b/drivers/dma/fsldma.c > > @@ -645,10 +645,9 @@ static dma_cookie_t fsl_dma_tx_submit(struct > dma_async_tx_descriptor *tx) > > struct fsldma_chan *chan = to_fsl_chan(tx->chan); > > struct fsl_desc_sw *desc = tx_to_fsl_desc(tx); > > struct fsl_desc_sw *child; > > - unsigned long flags; > > dma_cookie_t cookie; > > > > - spin_lock_irqsave(&chan->desc_lock, flags); > > + spin_lock_bh(&chan->desc_lock); > > > > /* > > * assign cookies to all of the software descriptors @@ -661,7 > > +660,7 @@ static dma_cookie_t fsl_dma_tx_submit(struct > dma_async_tx_descriptor *tx) > > /* put this transaction onto the tail of the pending queue */ > > append_ld_queue(chan, desc); > > > > - spin_unlock_irqrestore(&chan->desc_lock, flags); > > + spin_unlock_bh(&chan->desc_lock); > > > > return cookie; > > } > > @@ -770,15 +769,14 @@ static void fsldma_free_desc_list_reverse(struct > > fsldma_chan *chan, static void fsl_dma_free_chan_resources(struct > > dma_chan *dchan) { > > struct fsldma_chan *chan = to_fsl_chan(dchan); > > - unsigned long flags; > > > > chan_dbg(chan, "free all channel resources\n"); > > - spin_lock_irqsave(&chan->desc_lock, flags); > > + spin_lock_bh(&chan->desc_lock); > > fsldma_cleanup_descriptor(chan); > > fsldma_free_desc_list(chan, &chan->ld_pending); > > fsldma_free_desc_list(chan, &chan->ld_running); > > fsldma_free_desc_list(chan, &chan->ld_completed); > > - spin_unlock_irqrestore(&chan->desc_lock, flags); > > + spin_unlock_bh(&chan->desc_lock); > > > > dma_pool_destroy(chan->desc_pool); > > chan->desc_pool = NULL; > > @@ -997,7 +995,6 @@ static int fsl_dma_device_control(struct dma_chan > > *dchan, { > > struct dma_slave_config *config; > > struct fsldma_chan *chan; > > - unsigned long flags; > > int size; > > > > if (!dchan) > > @@ -1007,7 +1004,7 @@ static int fsl_dma_device_control(struct > > dma_chan *dchan, > > > > switch (cmd) { > > case DMA_TERMINATE_ALL: > > - spin_lock_irqsave(&chan->desc_lock, flags); > > + spin_lock_bh(&chan->desc_lock); > > > > /* Halt the DMA engine */ > > dma_halt(chan); > > @@ -1017,7 +1014,7 @@ static int fsl_dma_device_control(struct dma_chan > *dchan, > > fsldma_free_desc_list(chan, &chan->ld_running); > > chan->idle = true; > > > > - spin_unlock_irqrestore(&chan->desc_lock, flags); > > + spin_unlock_bh(&chan->desc_lock); > > return 0; > > > > case DMA_SLAVE_CONFIG: > > @@ -1059,11 +1056,10 @@ static int fsl_dma_device_control(struct > > dma_chan *dchan, static void fsl_dma_memcpy_issue_pending(struct > > dma_chan *dchan) { > > struct fsldma_chan *chan = to_fsl_chan(dchan); > > - unsigned long flags; > > > > - spin_lock_irqsave(&chan->desc_lock, flags); > > + spin_lock_bh(&chan->desc_lock); > > fsl_chan_xfer_ld_queue(chan); > > - spin_unlock_irqrestore(&chan->desc_lock, flags); > > + spin_unlock_bh(&chan->desc_lock); > > } > > > > /** > > @@ -1076,15 +1072,14 @@ static enum dma_status fsl_tx_status(struct > > dma_chan *dchan, { > > struct fsldma_chan *chan = to_fsl_chan(dchan); > > enum dma_status ret; > > - unsigned long flags; > > > > ret = dma_cookie_status(dchan, cookie, txstate); > > if (ret == DMA_SUCCESS) > > return ret; > > > > - spin_lock_irqsave(&chan->desc_lock, flags); > > + spin_lock_bh(&chan->desc_lock); > > fsldma_cleanup_descriptor(chan); > > - spin_unlock_irqrestore(&chan->desc_lock, flags); > > + spin_unlock_bh(&chan->desc_lock); > > > > return dma_cookie_status(dchan, cookie, txstate); } @@ -1163,11 > > +1158,10 @@ static irqreturn_t fsldma_chan_irq(int irq, void *data) > > static void dma_do_tasklet(unsigned long data) { > > struct fsldma_chan *chan = (struct fsldma_chan *)data; > > - unsigned long flags; > > > > chan_dbg(chan, "tasklet entry\n"); > > > > - spin_lock_irqsave(&chan->desc_lock, flags); > > + spin_lock_bh(&chan->desc_lock); > > > > /* the hardware is now idle and ready for more */ > > chan->idle = true; > > @@ -1175,7 +1169,7 @@ static void dma_do_tasklet(unsigned long data) > > /* Run all cleanup for this descriptor */ > > fsldma_cleanup_descriptor(chan); > > > > - spin_unlock_irqrestore(&chan->desc_lock, flags); > > + spin_unlock_bh(&chan->desc_lock); > > > > chan_dbg(chan, "tasklet exit\n"); > > } > > -- > > 1.7.5.1 > > > > > > _______________________________________________ > > Linuxppc-dev mailing list > > Linuxppc-dev@xxxxxxxxxxxxxxxx > > https://lists.ozlabs.org/listinfo/linuxppc-dev -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
