From patchwork Thu Aug 9 08:23:02 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Qiang Liu X-Patchwork-Id: 176027 X-Patchwork-Delegate: galak@kernel.crashing.org Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from ozlabs.org (localhost [IPv6:::1]) by ozlabs.org (Postfix) with ESMTP id 537192C0A23 for ; Thu, 9 Aug 2012 18:51:12 +1000 (EST) Received: from db3outboundpool.messaging.microsoft.com (db3ehsobe003.messaging.microsoft.com [213.199.154.141]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (Client CN "mail.global.frontbridge.com", Issuer "Microsoft Secure Server Authority" (not verified)) by ozlabs.org (Postfix) with ESMTPS id 2AF5D2C049A for ; Thu, 9 Aug 2012 18:49:58 +1000 (EST) Received: from mail49-db3-R.bigfish.com (10.3.81.253) by DB3EHSOBE002.bigfish.com (10.3.84.22) with Microsoft SMTP Server id 14.1.225.23; Thu, 9 Aug 2012 08:49:53 +0000 Received: from mail49-db3 (localhost [127.0.0.1]) by mail49-db3-R.bigfish.com (Postfix) with ESMTP id BB8C43200E0; Thu, 9 Aug 2012 08:49:53 +0000 (UTC) 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) Received: from mail49-db3 (localhost.localdomain [127.0.0.1]) by mail49-db3 (MessageSwitch) id 1344502192469910_26270; Thu, 9 Aug 2012 08:49:52 +0000 (UTC) Received: from DB3EHSMHS009.bigfish.com (unknown [10.3.81.239]) by mail49-db3.bigfish.com (Postfix) with ESMTP id 6647E2C00BF; Thu, 9 Aug 2012 08:49:52 +0000 (UTC) Received: from mail.freescale.net (70.37.183.190) by DB3EHSMHS009.bigfish.com (10.3.87.109) with Microsoft SMTP Server (TLS) id 14.1.225.23; Thu, 9 Aug 2012 08:49:48 +0000 Received: from az84smr01.freescale.net (10.64.34.197) by 039-SN1MMR1-004.039d.mgd.msft.net (10.84.1.14) with Microsoft SMTP Server (TLS) id 14.2.298.5; Thu, 9 Aug 2012 03:49:45 -0500 Received: from localhost (rock.ap.freescale.net [10.193.20.106]) by az84smr01.freescale.net (8.14.3/8.14.0) with ESMTP id q798nijO027732; Thu, 9 Aug 2012 01:49:45 -0700 From: To: , , , , , Subject: [PATCH v7 6/8] fsl-dma: use spin_lock_bh to instead of spin_lock_irqsave Date: Thu, 9 Aug 2012 16:23:02 +0800 Message-ID: <1344500582-11110-1-git-send-email-qiang.liu@freescale.com> X-Mailer: git-send-email 1.7.5.1 MIME-Version: 1.0 X-OriginatorOrg: freescale.com Cc: arnd@arndb.de, gregkh@linuxfoundation.org, Timur Tabi , Qiang Liu , herbert@gondor.hengli.com.au, davem@davemloft.net X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" 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 Acked-by: Arnd Bergmann --- Comments by Arnd Bergmann in v6: "You could actually change the use of spin_lock_bh inside of the tasklet function (dma_do_tasklet) do just spin_lock(), because softirqs are already disabled there, but your version is also ok." drivers/dma/fsldma.c | 30 ++++++++++++------------------ 1 files changed, 12 insertions(+), 18 deletions(-) -- 1.7.5.1 diff --git a/drivers/dma/fsldma.c b/drivers/dma/fsldma.c index b05a81f..8b9c0f7 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; } @@ -762,15 +761,14 @@ 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; @@ -989,7 +987,6 @@ 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) @@ -999,7 +996,7 @@ 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); @@ -1010,7 +1007,7 @@ 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: @@ -1052,11 +1049,10 @@ 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); } /** @@ -1069,15 +1065,14 @@ 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); } @@ -1156,11 +1151,10 @@ 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; @@ -1168,7 +1162,7 @@ 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"); }