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Message-ID: <BCB48C05FCE8BC4D9E61E841ECBE6DB70DFD24@039-SN2MPN1-013.039d.mgd.msft.net>
Date: Mon, 6 Aug 2012 11:01:37 +0000
From: Liu Qiang-B32616 <B32616@...escale.com>
To: Liu Qiang-B32616 <B32616@...escale.com>,
"linux-crypto@...r.kernel.org" <linux-crypto@...r.kernel.org>,
"linuxppc-dev@...ts.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>,
"dan.j.williams@...el.com" <dan.j.williams@...el.com>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"dan.j.williams@...il.com" <dan.j.williams@...il.com>,
"vinod.koul@...el.com" <vinod.koul@...el.com>
CC: Phillips Kim-R1AAHA <R1AAHA@...escale.com>,
"herbert@...dor.hengli.com.au" <herbert@...dor.hengli.com.au>,
"davem@...emloft.net" <davem@...emloft.net>,
"arnd@...db.de" <arnd@...db.de>,
"gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
Li Yang-R58472 <r58472@...escale.com>,
Tabi Timur-B04825 <B04825@...escale.com>
Subject: RE: [PATCH 6/8] fsl-dma: use spin_lock_bh to instead of
spin_lock_irqsave
Hi all,
Please ignore this one. Thanks.
> -----Original Message-----
> From: Liu Qiang-B32616
> Sent: Monday, August 06, 2012 6:15 PM
> To: linux-crypto@...r.kernel.org; linuxppc-dev@...ts.ozlabs.org;
> dan.j.williams@...el.com; linux-kernel@...r.kernel.org;
> dan.j.williams@...il.com; vinod.koul@...el.com
> Cc: Phillips Kim-R1AAHA; herbert@...dor.hengli.com.au;
> davem@...emloft.net; arnd@...db.de; gregkh@...uxfoundation.org; Liu
> Qiang-B32616; Li Yang-R58472; Tabi Timur-B04825
> Subject: [PATCH 6/8] fsl-dma: use spin_lock_bh to instead of
> spin_lock_irqsave
>
> From: Qiang Liu <qiang.liu@...escale.com>
>
> 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. Interrupts will be turned off and context will be saved,
> there is needless to use irqsave.
>
> 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.
>
> Cc: Dan Williams <dan.j.williams@...el.com>
> Cc: Dan Williams <dan.j.williams@...il.com>
> Cc: Vinod Koul <vinod.koul@...el.com>
> Cc: Li Yang <leoli@...escale.com>
> Cc: Timur Tabi <timur@...escale.com>
> Signed-off-by: Qiang Liu <qiang.liu@...escale.com>
> Acked-by: Ira W. Snyder <iws@...o.caltech.edu>
> ---
> 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 938d8c1..3f809df 100644
> --- a/drivers/dma/fsldma.c
> +++ b/drivers/dma/fsldma.c
> @@ -405,10 +405,9 @@ 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
> @@ -421,7 +420,7 @@ 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;
> }
> @@ -761,15 +760,14 @@ 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_descriptors(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;
> @@ -988,7 +986,6 @@ 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)
> @@ -998,7 +995,7 @@ 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);
> @@ -1009,7 +1006,7 @@ static int fsl_dma_device_control(struct dma_chan
> *dchan,
> fsldma_free_desc_list(chan, &chan->ld_completed);
> chan->idle = true;
>
> - spin_unlock_irqrestore(&chan->desc_lock, flags);
> + spin_unlock_bh(&chan->desc_lock);
> return 0;
>
> case DMA_SLAVE_CONFIG:
> @@ -1051,11 +1048,10 @@ 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);
> }
>
> /**
> @@ -1068,15 +1064,14 @@ 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_descriptors(chan);
> - spin_unlock_irqrestore(&chan->desc_lock, flags);
> + spin_unlock_bh(&chan->desc_lock);
>
> return dma_cookie_status(dchan, cookie, txstate);
> }
> @@ -1155,11 +1150,10 @@ 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;
> @@ -1167,7 +1161,7 @@ static void dma_do_tasklet(unsigned long data)
> /* Run all cleanup for descriptors which have been completed */
> fsldma_cleanup_descriptors(chan);
>
> - spin_unlock_irqrestore(&chan->desc_lock, flags);
> + spin_unlock_bh(&chan->desc_lock);
>
> chan_dbg(chan, "tasklet exit\n");
> }
> --
> 1.7.5.1
--
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