Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755851Ab2HFKmm (ORCPT ); Mon, 6 Aug 2012 06:42:42 -0400 Received: from [216.32.180.16] ([216.32.180.16]:7479 "EHLO va3outboundpool.messaging.microsoft.com" rhost-flags-FAIL-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1754659Ab2HFKmk (ORCPT ); Mon, 6 Aug 2012 06:42:40 -0400 X-Forefront-Antispam-Report: CIP:70.37.183.190;KIP:(null);UIP:(null);IPV:NLI;H:mail.freescale.net;RD:none;EFVD:NLI X-SpamScore: 0 X-BigFish: VS0(zzzz1202hzz8275bhz2dh2a8h668h839hd24he5bhf0ah107ah) From: To: , , , , , CC: , , , , , Qiang Liu , Li Yang , Timur Tabi Subject: [PATCH 6/8] fsl-dma: use spin_lock_bh to instead of spin_lock_irqsave Date: Mon, 6 Aug 2012 18:14:45 +0800 Message-ID: <1344248085-9315-1-git-send-email-qiang.liu@freescale.com> X-Mailer: git-send-email 1.7.5.1 MIME-Version: 1.0 Content-Type: text/plain X-OriginatorOrg: freescale.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5104 Lines: 154 From: Qiang Liu 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 Cc: Dan Williams Cc: Vinod Koul Cc: Li Yang Cc: Timur Tabi Signed-off-by: Qiang Liu Acked-by: Ira W. Snyder --- 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/