Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933963Ab3FSBNd (ORCPT ); Tue, 18 Jun 2013 21:13:33 -0400 Received: from mail-la0-f53.google.com ([209.85.215.53]:61223 "EHLO mail-la0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932644Ab3FSBNa (ORCPT ); Tue, 18 Jun 2013 21:13:30 -0400 MIME-Version: 1.0 In-Reply-To: <1371602813-19828-2-git-send-email-jon.mason@intel.com> References: <1371602813-19828-1-git-send-email-jon.mason@intel.com> <1371602813-19828-2-git-send-email-jon.mason@intel.com> Date: Tue, 18 Jun 2013 18:13:28 -0700 X-Google-Sender-Auth: UHIka6k-0tWgfGlwnzEev_NlIFo Message-ID: Subject: Re: [PATCH 1/2] dmadevices: dma_sync_wait undefined From: Dan Williams To: Jon Mason Cc: Vinod Koul , Dave Jiang , Linux Kernel Mailing List Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2370 Lines: 55 On Tue, Jun 18, 2013 at 5:46 PM, Jon Mason wrote: > dma_sync_wait is declared regardless of whether CONFIG_DMA_ENGINE is > enabled, but calling the function without CONFIG_DMA_ENGINE enabled > results in the following gcc error. > ERROR: "dma_sync_wait" [drivers/ntb/ntb.ko] undefined! > > To get around this, declare dma_sync_wait as an inline function if > CONFIG_DMA_ENGINE is undefined. > > Signed-off-by: Jon Mason > Acked-by: Dave Jiang > --- > include/linux/dmaengine.h | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h > index 96d3e4a..e3652ac 100644 > --- a/include/linux/dmaengine.h > +++ b/include/linux/dmaengine.h > @@ -963,8 +963,8 @@ dma_set_tx_state(struct dma_tx_state *st, dma_cookie_t last, dma_cookie_t used, > } > } > > -enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie); > #ifdef CONFIG_DMA_ENGINE > +enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie); > enum dma_status dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx); > void dma_issue_pending_all(void); > struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask, > @@ -972,6 +972,10 @@ struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask, > struct dma_chan *dma_request_slave_channel(struct device *dev, const char *name); > void dma_release_channel(struct dma_chan *chan); > #else > +static inline enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie) > +{ > + return DMA_SUCCESS; > +} Seems like something we should fix, but why is this not an indication that the code calling this is missing a "depends on DMA_ENGINE". On second look dma_sync_wait is a use as last resort hack that probably should not escape its internal use in dmaengine.c. The other escape in drivers/media/platform/timblogiw.c already looks problematic by having a live cpu spin immediately following a sleeping wait, obviously something event based was wanted. What's the use case in NTB? -- Dan -- 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/