Alsa-Devel Archive on lore.kernel.org
 help / color / Atom feed
From: Takashi Iwai <tiwai@suse.de>
To: alsa-devel@alsa-project.org
Subject: [alsa-devel] [PATCH 3/4] ALSA: pcm: Handle special page mapping in the default mmap handler
Date: Tue,  5 Nov 2019 09:01:37 +0100
Message-ID: <20191105080138.1260-4-tiwai@suse.de> (raw)
In-Reply-To: <20191105080138.1260-1-tiwai@suse.de>

When a driver needs to deal with a special buffer like a SG or a
vmalloc buffer, it has to set up the PCM page ops explicitly for the
corresponding helper function.  This is rather error-prone and many
people forgot or incorrectly used it.

For simplifying the call patterns and avoiding such a potential bug,
this patch enhances the PCM default mmap handler to check the
(pre-)allocated buffer type and handles the page gracefully depending
on the buffer type.  If the PCM page ops is given, the ops is still
used in a higher priority.  The new code path is only for the default
(NULL page ops) case.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 sound/core/pcm_native.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index c3a139436ac2..998c63192ae4 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -13,6 +13,7 @@
 #include <linux/pm_qos.h>
 #include <linux/io.h>
 #include <linux/dma-mapping.h>
+#include <linux/vmalloc.h>
 #include <sound/core.h>
 #include <sound/control.h>
 #include <sound/info.h>
@@ -3335,7 +3336,18 @@ static inline struct page *
 snd_pcm_default_page_ops(struct snd_pcm_substream *substream, unsigned long ofs)
 {
 	void *vaddr = substream->runtime->dma_area + ofs;
-	return virt_to_page(vaddr);
+
+	switch (substream->dma_buffer.dev.type) {
+#ifdef CONFIG_SND_DMA_SGBUF
+	case SNDRV_DMA_TYPE_DEV_SG:
+	case SNDRV_DMA_TYPE_DEV_UC_SG:
+		return snd_pcm_sgbuf_ops_page(substream, ofs);
+#endif /* CONFIG_SND_DMA_SGBUF */
+	case SNDRV_DMA_TYPE_VMALLOC:
+		return vmalloc_to_page(vaddr);
+	default:
+		return virt_to_page(vaddr);
+	}
 }
 
 /*
-- 
2.16.4

_______________________________________________
Alsa-devel mailing list
Alsa-devel@alsa-project.org
https://mailman.alsa-project.org/mailman/listinfo/alsa-devel

  parent reply index

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-05  8:01 [alsa-devel] [PATCH 0/4] ALSA: enhancement / cleanup on memalloc stuff Takashi Iwai
2019-11-05  8:01 ` [alsa-devel] [PATCH 1/4] ALSA: memalloc: Allow NULL device for SNDRV_DMA_TYPE_CONTINOUS type Takashi Iwai
2019-11-05 17:58   ` Ranjani Sridharan
2019-11-05 18:10     ` Takashi Iwai
2019-11-05 18:17       ` Sridharan, Ranjani
2019-11-05 18:46         ` Takashi Iwai
2019-11-05 18:28   ` Amadeusz Sławiński
2019-11-05 18:47     ` Takashi Iwai
2019-11-06 14:59   ` [alsa-devel] [PATCH v2] ALSA: memalloc: Allow NULL device for SNDRV_DMA_TYPE_CONTINUOUS type Takashi Iwai
2019-11-05  8:01 ` [alsa-devel] [PATCH 2/4] ALSA: memalloc: Add vmalloc buffer allocation support Takashi Iwai
2019-11-05  8:01 ` Takashi Iwai [this message]
2019-11-05  8:01 ` [alsa-devel] [PATCH 4/4] ALSA: docs: Update documentation about SG- and vmalloc-buffers Takashi Iwai

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20191105080138.1260-4-tiwai@suse.de \
    --to=tiwai@suse.de \
    --cc=alsa-devel@alsa-project.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Alsa-Devel Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/alsa-devel/0 alsa-devel/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 alsa-devel alsa-devel/ https://lore.kernel.org/alsa-devel \
		alsa-devel@alsa-project.org
	public-inbox-index alsa-devel

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.alsa-project.alsa-devel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git