[PATCH 0/2] mmc: allow mmc_alloc_host() and tmio_mmc_host_alloc()

[PATCH 0/2] mmc: allow mmc_alloc_host() and tmio_mmc_host_alloc()

[Masahiro Yamada]

sdhci_alloc_host() returns an error pointer when it fails.
but mmc_alloc_host() cannot.

This series allow to propagate a proper error code
when host-allocation fails.



Masahiro Yamada (2):
  mmc: allow mmc_alloc_host() to return proper error code
  mmc: tmio: allow tmio_mmc_host_alloc() to return proper error code

 drivers/mmc/core/host.c             | 11 ++++++-----
 drivers/mmc/host/android-goldfish.c |  4 ++--
 drivers/mmc/host/atmel-mci.c        |  4 ++--
 drivers/mmc/host/au1xmmc.c          |  4 ++--
 drivers/mmc/host/bfin_sdh.c         |  4 ++--
 drivers/mmc/host/cb710-mmc.c        |  4 ++--
 drivers/mmc/host/davinci_mmc.c      |  4 ++--
 drivers/mmc/host/dw_mmc.c           |  4 ++--
 drivers/mmc/host/jz4740_mmc.c       |  4 ++--
 drivers/mmc/host/mmc_spi.c          |  9 ++++++---
 drivers/mmc/host/mmci.c             |  4 ++--
 drivers/mmc/host/moxart-mmc.c       |  4 ++--
 drivers/mmc/host/mtk-sd.c           |  4 ++--
 drivers/mmc/host/mvsdio.c           |  4 ++--
 drivers/mmc/host/mxcmmc.c           |  4 ++--
 drivers/mmc/host/mxs-mmc.c          |  4 ++--
 drivers/mmc/host/omap.c             |  4 ++--
 drivers/mmc/host/omap_hsmmc.c       |  4 ++--
 drivers/mmc/host/pxamci.c           |  4 ++--
 drivers/mmc/host/rtsx_pci_sdmmc.c   |  4 ++--
 drivers/mmc/host/rtsx_usb_sdmmc.c   |  4 ++--
 drivers/mmc/host/s3cmci.c           |  4 ++--
 drivers/mmc/host/sdhci.c            |  4 ++--
 drivers/mmc/host/sdricoh_cs.c       |  4 ++--
 drivers/mmc/host/sh_mmcif.c         |  4 ++--
 drivers/mmc/host/sh_mobile_sdhi.c   |  4 ++--
 drivers/mmc/host/sunxi-mmc.c        |  4 ++--
 drivers/mmc/host/tifm_sd.c          |  4 ++--
 drivers/mmc/host/tmio_mmc.c         |  4 +++-
 drivers/mmc/host/tmio_mmc_pio.c     |  4 ++--
 drivers/mmc/host/toshsd.c           |  4 ++--
 drivers/mmc/host/usdhi6rol0.c       |  4 ++--
 drivers/mmc/host/ushc.c             |  4 ++--
 drivers/mmc/host/via-sdmmc.c        |  4 ++--
 drivers/mmc/host/vub300.c           |  4 ++--
 drivers/mmc/host/wbsd.c             |  4 ++--
 drivers/mmc/host/wmt-sdmmc.c        |  4 ++--
 drivers/staging/greybus/sdio.c      |  4 ++--
 38 files changed, 85 insertions(+), 79 deletions(-)

-- 
1.9.1

[PATCH 1/2] mmc: allow mmc_alloc_host() to return proper error code

[Masahiro Yamada]

Currently, mmc_alloc_host() returns NULL on error, so its callers
cannot return anything but -ENOMEM when it fails, assuming the most
failure cases are due to memory shortage, but it is not true.

Allow mmc_alloc_host() to return an error pointer, then propagate
the proper error code to its callers.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
---

 drivers/mmc/core/host.c             | 11 ++++++-----
 drivers/mmc/host/android-goldfish.c |  4 ++--
 drivers/mmc/host/atmel-mci.c        |  4 ++--
 drivers/mmc/host/au1xmmc.c          |  4 ++--
 drivers/mmc/host/bfin_sdh.c         |  4 ++--
 drivers/mmc/host/cb710-mmc.c        |  4 ++--
 drivers/mmc/host/davinci_mmc.c      |  4 ++--
 drivers/mmc/host/dw_mmc.c           |  4 ++--
 drivers/mmc/host/jz4740_mmc.c       |  4 ++--
 drivers/mmc/host/mmc_spi.c          |  9 ++++++---
 drivers/mmc/host/mmci.c             |  4 ++--
 drivers/mmc/host/moxart-mmc.c       |  4 ++--
 drivers/mmc/host/mtk-sd.c           |  4 ++--
 drivers/mmc/host/mvsdio.c           |  4 ++--
 drivers/mmc/host/mxcmmc.c           |  4 ++--
 drivers/mmc/host/mxs-mmc.c          |  4 ++--
 drivers/mmc/host/omap.c             |  4 ++--
 drivers/mmc/host/omap_hsmmc.c       |  4 ++--
 drivers/mmc/host/pxamci.c           |  4 ++--
 drivers/mmc/host/rtsx_pci_sdmmc.c   |  4 ++--
 drivers/mmc/host/rtsx_usb_sdmmc.c   |  4 ++--
 drivers/mmc/host/s3cmci.c           |  4 ++--
 drivers/mmc/host/sdhci.c            |  4 ++--
 drivers/mmc/host/sdricoh_cs.c       |  4 ++--
 drivers/mmc/host/sh_mmcif.c         |  4 ++--
 drivers/mmc/host/sunxi-mmc.c        |  4 ++--
 drivers/mmc/host/tifm_sd.c          |  4 ++--
 drivers/mmc/host/tmio_mmc_pio.c     |  2 +-
 drivers/mmc/host/toshsd.c           |  4 ++--
 drivers/mmc/host/usdhi6rol0.c       |  4 ++--
 drivers/mmc/host/ushc.c             |  4 ++--
 drivers/mmc/host/via-sdmmc.c        |  4 ++--
 drivers/mmc/host/vub300.c           |  4 ++--
 drivers/mmc/host/wbsd.c             |  4 ++--
 drivers/mmc/host/wmt-sdmmc.c        |  4 ++--
 drivers/staging/greybus/sdio.c      |  4 ++--
 36 files changed, 79 insertions(+), 75 deletions(-)

diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
index 98f25ff..b3e13e0 100644
--- a/drivers/mmc/core/host.c
+++ b/drivers/mmc/core/host.c
@@ -349,7 +349,7 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
 
 	host = kzalloc(sizeof(struct mmc_host) + extra, GFP_KERNEL);
 	if (!host)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 
 	/* scanning will be enabled when we're ready */
 	host->rescan_disable = 1;
@@ -357,7 +357,7 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
 again:
 	if (!ida_pre_get(&mmc_host_ida, GFP_KERNEL)) {
 		kfree(host);
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 	}
 
 	spin_lock(&mmc_host_lock);
@@ -368,7 +368,7 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
 		goto again;
 	} else if (err) {
 		kfree(host);
-		return NULL;
+		return ERR_PTR(err);
 	}
 
 	dev_set_name(&host->class_dev, "mmc%d", host->index);
@@ -379,9 +379,10 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
 	device_initialize(&host->class_dev);
 	device_enable_async_suspend(&host->class_dev);
 
-	if (mmc_gpio_alloc(host)) {
+	err = mmc_gpio_alloc(host);
+	if (err < 0) {
 		put_device(&host->class_dev);
-		return NULL;
+		return ERR_PTR(err);
 	}
 
 	spin_lock_init(&host->lock);
diff --git a/drivers/mmc/host/android-goldfish.c b/drivers/mmc/host/android-goldfish.c
index dca5518..7363663 100644
--- a/drivers/mmc/host/android-goldfish.c
+++ b/drivers/mmc/host/android-goldfish.c
@@ -467,8 +467,8 @@ static int goldfish_mmc_probe(struct platform_device *pdev)
 		return -ENXIO;
 
 	mmc = mmc_alloc_host(sizeof(struct goldfish_mmc_host), &pdev->dev);
-	if (mmc == NULL) {
-		ret = -ENOMEM;
+	if (IS_ERR(mmc)) {
+		ret = PTR_ERR(mmc);
 		goto err_alloc_host_failed;
 	}
 
diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c
index 0ad8ef5..d0cb112 100644
--- a/drivers/mmc/host/atmel-mci.c
+++ b/drivers/mmc/host/atmel-mci.c
@@ -2296,8 +2296,8 @@ static int atmci_init_slot(struct atmel_mci *host,
 	struct atmel_mci_slot		*slot;
 
 	mmc = mmc_alloc_host(sizeof(struct atmel_mci_slot), &host->pdev->dev);
-	if (!mmc)
-		return -ENOMEM;
+	if (IS_ERR(mmc))
+		return PTR_ERR(mmc);
 
 	slot = mmc_priv(mmc);
 	slot->mmc = mmc;
diff --git a/drivers/mmc/host/au1xmmc.c b/drivers/mmc/host/au1xmmc.c
index ed77fbfa..d97b409 100644
--- a/drivers/mmc/host/au1xmmc.c
+++ b/drivers/mmc/host/au1xmmc.c
@@ -951,9 +951,9 @@ static int au1xmmc_probe(struct platform_device *pdev)
 	int ret, iflag;
 
 	mmc = mmc_alloc_host(sizeof(struct au1xmmc_host), &pdev->dev);
-	if (!mmc) {
+	if (IS_ERR(mmc)) {
 		dev_err(&pdev->dev, "no memory for mmc_host\n");
-		ret = -ENOMEM;
+		ret = PTR_ERR(mmc);
 		goto out0;
 	}
 
diff --git a/drivers/mmc/host/bfin_sdh.c b/drivers/mmc/host/bfin_sdh.c
index 526231e..60c52d1 100644
--- a/drivers/mmc/host/bfin_sdh.c
+++ b/drivers/mmc/host/bfin_sdh.c
@@ -532,8 +532,8 @@ static int sdh_probe(struct platform_device *pdev)
 	}
 
 	mmc = mmc_alloc_host(sizeof(struct sdh_host), &pdev->dev);
-	if (!mmc) {
-		ret = -ENOMEM;
+	if (IS_ERR(mmc)) {
+		ret = PTR_ERR(mmc);
 		goto out;
 	}
 
diff --git a/drivers/mmc/host/cb710-mmc.c b/drivers/mmc/host/cb710-mmc.c
index 1087b4c..79ce871 100644
--- a/drivers/mmc/host/cb710-mmc.c
+++ b/drivers/mmc/host/cb710-mmc.c
@@ -692,8 +692,8 @@ static int cb710_mmc_init(struct platform_device *pdev)
 	u32 val;
 
 	mmc = mmc_alloc_host(sizeof(*reader), cb710_slot_dev(slot));
-	if (!mmc)
-		return -ENOMEM;
+	if (IS_ERR(mmc))
+		return PTR_ERR(mmc);
 
 	platform_set_drvdata(pdev, mmc);
 
diff --git a/drivers/mmc/host/davinci_mmc.c b/drivers/mmc/host/davinci_mmc.c
index 8fa478c..225b9a8 100644
--- a/drivers/mmc/host/davinci_mmc.c
+++ b/drivers/mmc/host/davinci_mmc.c
@@ -1229,8 +1229,8 @@ static int __init davinci_mmcsd_probe(struct platform_device *pdev)
 		return -EBUSY;
 
 	mmc = mmc_alloc_host(sizeof(struct mmc_davinci_host), &pdev->dev);
-	if (!mmc)
-		return -ENOMEM;
+	if (IS_ERR(mmc))
+		return PTR_ERR(mmc);
 
 	host = mmc_priv(mmc);
 	host->mmc = mmc;	/* Important */
diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index 4fcbc40..4f06528 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -2598,8 +2598,8 @@ static int dw_mci_init_slot(struct dw_mci *host, unsigned int id)
 	u32 freq[2];
 
 	mmc = mmc_alloc_host(sizeof(struct dw_mci_slot), host->dev);
-	if (!mmc)
-		return -ENOMEM;
+	if (IS_ERR(mmc))
+		return PTR_ERR(mmc);
 
 	slot = mmc_priv(mmc);
 	slot->id = id;
diff --git a/drivers/mmc/host/jz4740_mmc.c b/drivers/mmc/host/jz4740_mmc.c
index 684087d..351dd68 100644
--- a/drivers/mmc/host/jz4740_mmc.c
+++ b/drivers/mmc/host/jz4740_mmc.c
@@ -998,9 +998,9 @@ static int jz4740_mmc_probe(struct platform_device* pdev)
 	pdata = pdev->dev.platform_data;
 
 	mmc = mmc_alloc_host(sizeof(struct jz4740_mmc_host), &pdev->dev);
-	if (!mmc) {
+	if (IS_ERR(mmc)) {
 		dev_err(&pdev->dev, "Failed to alloc mmc host structure\n");
-		return -ENOMEM;
+		return PTR_ERR(mmc);
 	}
 
 	host = mmc_priv(mmc);
diff --git a/drivers/mmc/host/mmc_spi.c b/drivers/mmc/host/mmc_spi.c
index e77d79c..165f73e 100644
--- a/drivers/mmc/host/mmc_spi.c
+++ b/drivers/mmc/host/mmc_spi.c
@@ -1333,15 +1333,18 @@ static int mmc_spi_probe(struct spi_device *spi)
 	 * NOTE if many systems use more than one MMC-over-SPI connector
 	 * it'd save some memory to share this.  That's evidently rare.
 	 */
-	status = -ENOMEM;
 	ones = kmalloc(MMC_SPI_BLOCKSIZE, GFP_KERNEL);
-	if (!ones)
+	if (!ones) {
+		status = -ENOMEM;
 		goto nomem;
+	}
 	memset(ones, 0xff, MMC_SPI_BLOCKSIZE);
 
 	mmc = mmc_alloc_host(sizeof(*host), &spi->dev);
-	if (!mmc)
+	if (IS_ERR(mmc)) {
+		status = PTR_ERR(mmc);
 		goto nomem;
+	}
 
 	mmc->ops = &mmc_spi_ops;
 	mmc->max_blk_size = MMC_SPI_BLOCKSIZE;
diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
index df990bb..5779b57 100644
--- a/drivers/mmc/host/mmci.c
+++ b/drivers/mmc/host/mmci.c
@@ -1509,8 +1509,8 @@ static int mmci_probe(struct amba_device *dev,
 	}
 
 	mmc = mmc_alloc_host(sizeof(struct mmci_host), &dev->dev);
-	if (!mmc)
-		return -ENOMEM;
+	if (IS_ERR(mmc))
+		return PTR_ERR(mmc);
 
 	ret = mmci_of_parse(np, mmc);
 	if (ret)
diff --git a/drivers/mmc/host/moxart-mmc.c b/drivers/mmc/host/moxart-mmc.c
index bbad309..f453e55 100644
--- a/drivers/mmc/host/moxart-mmc.c
+++ b/drivers/mmc/host/moxart-mmc.c
@@ -568,9 +568,9 @@ static int moxart_probe(struct platform_device *pdev)
 	u32 i;
 
 	mmc = mmc_alloc_host(sizeof(struct moxart_host), dev);
-	if (!mmc) {
+	if (IS_ERR(mmc)) {
 		dev_err(dev, "mmc_alloc_host failed\n");
-		ret = -ENOMEM;
+		ret = PTR_ERR(mmc);
 		goto out;
 	}
 
diff --git a/drivers/mmc/host/mtk-sd.c b/drivers/mmc/host/mtk-sd.c
index 84e9afc..ef28f64 100644
--- a/drivers/mmc/host/mtk-sd.c
+++ b/drivers/mmc/host/mtk-sd.c
@@ -1494,8 +1494,8 @@ static int msdc_drv_probe(struct platform_device *pdev)
 	}
 	/* Allocate MMC host for this device */
 	mmc = mmc_alloc_host(sizeof(struct msdc_host), &pdev->dev);
-	if (!mmc)
-		return -ENOMEM;
+	if (IS_ERR(mmc))
+		return PTR_ERR(mmc);
 
 	host = mmc_priv(mmc);
 	ret = mmc_of_parse(mmc);
diff --git a/drivers/mmc/host/mvsdio.c b/drivers/mmc/host/mvsdio.c
index 42296e5..5594f58 100644
--- a/drivers/mmc/host/mvsdio.c
+++ b/drivers/mmc/host/mvsdio.c
@@ -711,8 +711,8 @@ static int mvsd_probe(struct platform_device *pdev)
 		return -ENXIO;
 
 	mmc = mmc_alloc_host(sizeof(struct mvsd_host), &pdev->dev);
-	if (!mmc) {
-		ret = -ENOMEM;
+	if (IS_ERR(mmc)) {
+		ret = PTR_ERR(mmc);
 		goto out;
 	}
 
diff --git a/drivers/mmc/host/mxcmmc.c b/drivers/mmc/host/mxcmmc.c
index fb3ca82..5bdc644 100644
--- a/drivers/mmc/host/mxcmmc.c
+++ b/drivers/mmc/host/mxcmmc.c
@@ -1018,8 +1018,8 @@ static int mxcmci_probe(struct platform_device *pdev)
 		return -EINVAL;
 
 	mmc = mmc_alloc_host(sizeof(*host), &pdev->dev);
-	if (!mmc)
-		return -ENOMEM;
+	if (IS_ERR(mmc))
+		return PTR_ERR(mmc);
 
 	host = mmc_priv(mmc);
 
diff --git a/drivers/mmc/host/mxs-mmc.c b/drivers/mmc/host/mxs-mmc.c
index d839147..7f72bb4 100644
--- a/drivers/mmc/host/mxs-mmc.c
+++ b/drivers/mmc/host/mxs-mmc.c
@@ -586,8 +586,8 @@ static int mxs_mmc_probe(struct platform_device *pdev)
 		return irq_err;
 
 	mmc = mmc_alloc_host(sizeof(struct mxs_mmc_host), &pdev->dev);
-	if (!mmc)
-		return -ENOMEM;
+	if (IS_ERR(mmc))
+		return PTR_ERR(mmc);
 
 	host = mmc_priv(mmc);
 	ssp = &host->ssp;
diff --git a/drivers/mmc/host/omap.c b/drivers/mmc/host/omap.c
index be3c49f..b1ec63f 100644
--- a/drivers/mmc/host/omap.c
+++ b/drivers/mmc/host/omap.c
@@ -1227,8 +1227,8 @@ static int mmc_omap_new_slot(struct mmc_omap_host *host, int id)
 	int r;
 
 	mmc = mmc_alloc_host(sizeof(struct mmc_omap_slot), host->dev);
-	if (mmc == NULL)
-		return -ENOMEM;
+	if (IS_ERR(mmc))
+		return PTR_ERR(mmc);
 
 	slot = mmc_priv(mmc);
 	slot->host = host;
diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c
index 5f2f24a..6154b55 100644
--- a/drivers/mmc/host/omap_hsmmc.c
+++ b/drivers/mmc/host/omap_hsmmc.c
@@ -2024,8 +2024,8 @@ static int omap_hsmmc_probe(struct platform_device *pdev)
 		return PTR_ERR(base);
 
 	mmc = mmc_alloc_host(sizeof(struct omap_hsmmc_host), &pdev->dev);
-	if (!mmc) {
-		ret = -ENOMEM;
+	if (IS_ERR(mmc)) {
+		ret = PTR_ERR(mmc);
 		goto err;
 	}
 
diff --git a/drivers/mmc/host/pxamci.c b/drivers/mmc/host/pxamci.c
index c763b40..9e9b02f 100644
--- a/drivers/mmc/host/pxamci.c
+++ b/drivers/mmc/host/pxamci.c
@@ -652,8 +652,8 @@ static int pxamci_probe(struct platform_device *pdev)
 		return irq;
 
 	mmc = mmc_alloc_host(sizeof(struct pxamci_host), &pdev->dev);
-	if (!mmc) {
-		ret = -ENOMEM;
+	if (IS_ERR(mmc)) {
+		ret = PTR_ERR(mmc);
 		goto out;
 	}
 
diff --git a/drivers/mmc/host/rtsx_pci_sdmmc.c b/drivers/mmc/host/rtsx_pci_sdmmc.c
index 3ccaa14..551536e 100644
--- a/drivers/mmc/host/rtsx_pci_sdmmc.c
+++ b/drivers/mmc/host/rtsx_pci_sdmmc.c
@@ -1399,8 +1399,8 @@ static int rtsx_pci_sdmmc_drv_probe(struct platform_device *pdev)
 	dev_dbg(&(pdev->dev), ": Realtek PCI-E SDMMC controller found\n");
 
 	mmc = mmc_alloc_host(sizeof(*host), &pdev->dev);
-	if (!mmc)
-		return -ENOMEM;
+	if (IS_ERR(mmc))
+		return PTR_ERR(mmc);
 
 	host = mmc_priv(mmc);
 	host->pcr = pcr;
diff --git a/drivers/mmc/host/rtsx_usb_sdmmc.c b/drivers/mmc/host/rtsx_usb_sdmmc.c
index 6e9c0f8..443679f 100644
--- a/drivers/mmc/host/rtsx_usb_sdmmc.c
+++ b/drivers/mmc/host/rtsx_usb_sdmmc.c
@@ -1363,8 +1363,8 @@ static int rtsx_usb_sdmmc_drv_probe(struct platform_device *pdev)
 	dev_dbg(&(pdev->dev), ": Realtek USB SD/MMC controller found\n");
 
 	mmc = mmc_alloc_host(sizeof(*host), &pdev->dev);
-	if (!mmc)
-		return -ENOMEM;
+	if (IS_ERR(mmc))
+		return PTR_ERR(mmc);
 
 	host = mmc_priv(mmc);
 	host->ucr = ucr;
diff --git a/drivers/mmc/host/s3cmci.c b/drivers/mmc/host/s3cmci.c
index c531dee..aacc5cf 100644
--- a/drivers/mmc/host/s3cmci.c
+++ b/drivers/mmc/host/s3cmci.c
@@ -1556,8 +1556,8 @@ static int s3cmci_probe(struct platform_device *pdev)
 	is2440 = platform_get_device_id(pdev)->driver_data;
 
 	mmc = mmc_alloc_host(sizeof(struct s3cmci_host), &pdev->dev);
-	if (!mmc) {
-		ret = -ENOMEM;
+	if (IS_ERR(mmc)) {
+		ret = PTR_ERR(mmc);
 		goto probe_out;
 	}
 
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 71654b9..eb8199e 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2946,8 +2946,8 @@ struct sdhci_host *sdhci_alloc_host(struct device *dev,
 	WARN_ON(dev == NULL);
 
 	mmc = mmc_alloc_host(sizeof(struct sdhci_host) + priv_size, dev);
-	if (!mmc)
-		return ERR_PTR(-ENOMEM);
+	if (IS_ERR(mmc))
+		return ERR_CAST(mmc);
 
 	host = mmc_priv(mmc);
 	host->mmc = mmc;
diff --git a/drivers/mmc/host/sdricoh_cs.c b/drivers/mmc/host/sdricoh_cs.c
index 5ff26ab..6d2f671 100644
--- a/drivers/mmc/host/sdricoh_cs.c
+++ b/drivers/mmc/host/sdricoh_cs.c
@@ -424,9 +424,9 @@ static int sdricoh_init_mmc(struct pci_dev *pci_dev,
 	/* allocate privdata */
 	mmc = pcmcia_dev->priv =
 	    mmc_alloc_host(sizeof(struct sdricoh_host), &pcmcia_dev->dev);
-	if (!mmc) {
+	if (IS_ERR(mmc)) {
 		dev_err(dev, "mmc_alloc_host failed\n");
-		result = -ENOMEM;
+		result = PTR_ERR(mmc);
 		goto unmap_io;
 	}
 	host = mmc_priv(mmc);
diff --git a/drivers/mmc/host/sh_mmcif.c b/drivers/mmc/host/sh_mmcif.c
index 9007784..c2affc6 100644
--- a/drivers/mmc/host/sh_mmcif.c
+++ b/drivers/mmc/host/sh_mmcif.c
@@ -1432,8 +1432,8 @@ static int sh_mmcif_probe(struct platform_device *pdev)
 		return PTR_ERR(reg);
 
 	mmc = mmc_alloc_host(sizeof(struct sh_mmcif_host), dev);
-	if (!mmc)
-		return -ENOMEM;
+	if (IS_ERR(mmc))
+		return PTR_ERR(mmc);
 
 	ret = mmc_of_parse(mmc);
 	if (ret < 0)
diff --git a/drivers/mmc/host/sunxi-mmc.c b/drivers/mmc/host/sunxi-mmc.c
index c0a5c67..a3cb388 100644
--- a/drivers/mmc/host/sunxi-mmc.c
+++ b/drivers/mmc/host/sunxi-mmc.c
@@ -1212,9 +1212,9 @@ static int sunxi_mmc_probe(struct platform_device *pdev)
 	int ret;
 
 	mmc = mmc_alloc_host(sizeof(struct sunxi_mmc_host), &pdev->dev);
-	if (!mmc) {
+	if (IS_ERR(mmc)) {
 		dev_err(&pdev->dev, "mmc alloc host failed\n");
-		return -ENOMEM;
+		return PTR_ERR(mmc);
 	}
 
 	host = mmc_priv(mmc);
diff --git a/drivers/mmc/host/tifm_sd.c b/drivers/mmc/host/tifm_sd.c
index 93c4b40..b088cb8 100644
--- a/drivers/mmc/host/tifm_sd.c
+++ b/drivers/mmc/host/tifm_sd.c
@@ -958,8 +958,8 @@ static int tifm_sd_probe(struct tifm_dev *sock)
 	}
 
 	mmc = mmc_alloc_host(sizeof(struct tifm_sd), &sock->dev);
-	if (!mmc)
-		return -ENOMEM;
+	if (IS_ERR(mmc))
+		return PTR_ERR(mmc);
 
 	host = mmc_priv(mmc);
 	tifm_set_drvdata(sock, mmc);
diff --git a/drivers/mmc/host/tmio_mmc_pio.c b/drivers/mmc/host/tmio_mmc_pio.c
index 7005676..18106fc 100644
--- a/drivers/mmc/host/tmio_mmc_pio.c
+++ b/drivers/mmc/host/tmio_mmc_pio.c
@@ -1013,7 +1013,7 @@ struct tmio_mmc_host*
 	struct mmc_host *mmc;
 
 	mmc = mmc_alloc_host(sizeof(struct tmio_mmc_host), &pdev->dev);
-	if (!mmc)
+	if (IS_ERR(mmc))
 		return NULL;
 
 	host = mmc_priv(mmc);
diff --git a/drivers/mmc/host/toshsd.c b/drivers/mmc/host/toshsd.c
index 553ef41..7b086ed 100644
--- a/drivers/mmc/host/toshsd.c
+++ b/drivers/mmc/host/toshsd.c
@@ -617,8 +617,8 @@ static int toshsd_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 		return ret;
 
 	mmc = mmc_alloc_host(sizeof(struct toshsd_host), &pdev->dev);
-	if (!mmc) {
-		ret = -ENOMEM;
+	if (IS_ERR(mmc)) {
+		ret = PTR_ERR(mmc);
 		goto err;
 	}
 
diff --git a/drivers/mmc/host/usdhi6rol0.c b/drivers/mmc/host/usdhi6rol0.c
index 1bd5f1a..e9d0126 100644
--- a/drivers/mmc/host/usdhi6rol0.c
+++ b/drivers/mmc/host/usdhi6rol0.c
@@ -1753,8 +1753,8 @@ static int usdhi6_probe(struct platform_device *pdev)
 		return -ENODEV;
 
 	mmc = mmc_alloc_host(sizeof(struct usdhi6_host), dev);
-	if (!mmc)
-		return -ENOMEM;
+	if (IS_ERR(mmc))
+		return PTR_ERR(mmc);
 
 	ret = mmc_regulator_get_supply(mmc);
 	if (ret == -EPROBE_DEFER)
diff --git a/drivers/mmc/host/ushc.c b/drivers/mmc/host/ushc.c
index d2c386f..6937021 100644
--- a/drivers/mmc/host/ushc.c
+++ b/drivers/mmc/host/ushc.c
@@ -427,8 +427,8 @@ static int ushc_probe(struct usb_interface *intf, const struct usb_device_id *id
 	int ret;
 
 	mmc = mmc_alloc_host(sizeof(struct ushc_data), &intf->dev);
-	if (mmc == NULL)
-		return -ENOMEM;
+	if (IS_ERR(mmc))
+		return PTR_ERR(mmc);
 	ushc = mmc_priv(mmc);
 	usb_set_intfdata(intf, ushc);
 
diff --git a/drivers/mmc/host/via-sdmmc.c b/drivers/mmc/host/via-sdmmc.c
index 63fac78..010bfdb 100644
--- a/drivers/mmc/host/via-sdmmc.c
+++ b/drivers/mmc/host/via-sdmmc.c
@@ -1108,8 +1108,8 @@ static int via_sd_probe(struct pci_dev *pcidev,
 	pci_write_config_byte(pcidev, VIA_CRDR_PCI_DBG_MODE, 0);
 
 	mmc = mmc_alloc_host(sizeof(struct via_crdr_mmc_host), &pcidev->dev);
-	if (!mmc) {
-		ret = -ENOMEM;
+	if (IS_ERR(mmc)) {
+		ret = PTR_ERR(mmc);
 		goto release;
 	}
 
diff --git a/drivers/mmc/host/vub300.c b/drivers/mmc/host/vub300.c
index bb3e0d1..d052c23 100644
--- a/drivers/mmc/host/vub300.c
+++ b/drivers/mmc/host/vub300.c
@@ -2125,8 +2125,8 @@ static int vub300_probe(struct usb_interface *interface,
 	}
 	/* this also allocates memory for our VUB300 mmc host device */
 	mmc = mmc_alloc_host(sizeof(struct vub300_mmc_host), &udev->dev);
-	if (!mmc) {
-		retval = -ENOMEM;
+	if (IS_ERR(mmc)) {
+		retval = PTR_ERR(mmc);
 		dev_err(&udev->dev, "not enough memory for the mmc_host\n");
 		goto error4;
 	}
diff --git a/drivers/mmc/host/wbsd.c b/drivers/mmc/host/wbsd.c
index c3fd16d..40f8fd6 100644
--- a/drivers/mmc/host/wbsd.c
+++ b/drivers/mmc/host/wbsd.c
@@ -1204,8 +1204,8 @@ static int wbsd_alloc_mmc(struct device *dev)
 	 * Allocate MMC structure.
 	 */
 	mmc = mmc_alloc_host(sizeof(struct wbsd_host), dev);
-	if (!mmc)
-		return -ENOMEM;
+	if (IS_ERR(mmc))
+		return PTR_ERR(mmc);
 
 	host = mmc_priv(mmc);
 	host->mmc = mmc;
diff --git a/drivers/mmc/host/wmt-sdmmc.c b/drivers/mmc/host/wmt-sdmmc.c
index 5af0055..f37f9a4cd 100644
--- a/drivers/mmc/host/wmt-sdmmc.c
+++ b/drivers/mmc/host/wmt-sdmmc.c
@@ -782,9 +782,9 @@ static int wmt_mci_probe(struct platform_device *pdev)
 	}
 
 	mmc = mmc_alloc_host(sizeof(struct wmt_mci_priv), &pdev->dev);
-	if (!mmc) {
+	if (IS_ERR(mmc)) {
 		dev_err(&pdev->dev, "Failed to allocate mmc_host\n");
-		ret = -ENOMEM;
+		ret = PTR_ERR(mmc);
 		goto fail1;
 	}
 
diff --git a/drivers/staging/greybus/sdio.c b/drivers/staging/greybus/sdio.c
index 5649ef1..01c443d 100644
--- a/drivers/staging/greybus/sdio.c
+++ b/drivers/staging/greybus/sdio.c
@@ -768,8 +768,8 @@ static int gb_sdio_probe(struct gbphy_device *gbphy_dev,
 	int ret = 0;
 
 	mmc = mmc_alloc_host(sizeof(*host), &gbphy_dev->dev);
-	if (!mmc)
-		return -ENOMEM;
+	if (IS_ERR(mmc))
+		return PTR_ERR(mmc);
 
 	connection = gb_connection_create(gbphy_dev->bundle,
 					  le16_to_cpu(gbphy_dev->cport_desc->id),
-- 
1.9.1

[PATCH 2/2] mmc: tmio: allow tmio_mmc_host_alloc() to return proper error code

[Masahiro Yamada]

Now, mmc_alloc_host() returns an error pointer when it fails.
So, tmio_mmc_host_alloc() can also return an error pointer to
propagate the proper error code.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
---

 drivers/mmc/host/sh_mobile_sdhi.c | 4 ++--
 drivers/mmc/host/tmio_mmc.c       | 4 +++-
 drivers/mmc/host/tmio_mmc_pio.c   | 2 +-
 3 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/mmc/host/sh_mobile_sdhi.c b/drivers/mmc/host/sh_mobile_sdhi.c
index 49edff7..97a796c 100644
--- a/drivers/mmc/host/sh_mobile_sdhi.c
+++ b/drivers/mmc/host/sh_mobile_sdhi.c
@@ -355,8 +355,8 @@ static int sh_mobile_sdhi_probe(struct platform_device *pdev)
 	}
 
 	host = tmio_mmc_host_alloc(pdev);
-	if (!host) {
-		ret = -ENOMEM;
+	if (IS_ERR(host)) {
+		ret = PTR_ERR(host);
 		goto eprobe;
 	}
 
diff --git a/drivers/mmc/host/tmio_mmc.c b/drivers/mmc/host/tmio_mmc.c
index e897e7f..3316545 100644
--- a/drivers/mmc/host/tmio_mmc.c
+++ b/drivers/mmc/host/tmio_mmc.c
@@ -93,8 +93,10 @@ static int tmio_mmc_probe(struct platform_device *pdev)
 	pdata->flags |= TMIO_MMC_HAVE_HIGH_REG;
 
 	host = tmio_mmc_host_alloc(pdev);
-	if (!host)
+	if (IS_ERR(host)) {
+		ret = PTR_ERR(host);
 		goto cell_disable;
+	}
 
 	/* SD control register space size is 0x200, 0x400 for bus_shift=1 */
 	host->bus_shift = resource_size(res) >> 10;
diff --git a/drivers/mmc/host/tmio_mmc_pio.c b/drivers/mmc/host/tmio_mmc_pio.c
index 18106fc..7e8c80e 100644
--- a/drivers/mmc/host/tmio_mmc_pio.c
+++ b/drivers/mmc/host/tmio_mmc_pio.c
@@ -1014,7 +1014,7 @@ struct tmio_mmc_host*
 
 	mmc = mmc_alloc_host(sizeof(struct tmio_mmc_host), &pdev->dev);
 	if (IS_ERR(mmc))
-		return NULL;
+		return ERR_CAST(mmc);
 
 	host = mmc_priv(mmc);
 	host->mmc = mmc;
-- 
1.9.1

Re: [PATCH 0/2] mmc: allow mmc_alloc_host() and tmio_mmc_host_alloc()

[Greg Kroah-Hartman]

On Thu, Nov 10, 2016 at 10:24:21PM +0900, Masahiro Yamada wrote:
> 
> sdhci_alloc_host() returns an error pointer when it fails.
> but mmc_alloc_host() cannot.
> 
> This series allow to propagate a proper error code
> when host-allocation fails.

Why?  What can we really do about the error except give up?  Why does
having a explicit error value make any difference to the caller, they
can't do anything different, right?

I suggest just leaving it as-is, it's simple, and you don't have to mess
with PTR_ERR() anywhere.

thanks,

greg k-h

Re: [PATCH 0/2] mmc: allow mmc_alloc_host() and tmio_mmc_host_alloc()

[Masahiro Yamada]

2016-11-10 22:35 GMT+09:00 Greg Kroah-Hartman <gregkh@linuxfoundation.org>:
> On Thu, Nov 10, 2016 at 10:24:21PM +0900, Masahiro Yamada wrote:
>>
>> sdhci_alloc_host() returns an error pointer when it fails.
>> but mmc_alloc_host() cannot.
>>
>> This series allow to propagate a proper error code
>> when host-allocation fails.
>
> Why?  What can we really do about the error except give up?  Why does
> having a explicit error value make any difference to the caller, they
> can't do anything different, right?


The error code is shown in the console, like

  probe of 5a000000.sdhc failed with error -12


The proper error code will give a clue
why the driver failed to probe.


> I suggest just leaving it as-is, it's simple, and you don't have to mess
> with PTR_ERR() anywhere.


Why?

Most of driver just give up probing for any error,
but we still do ERR_PTR()/PTR_ERR() here and there.
I think this patch is the same pattern.

If a function returns NULL on failure, we need to think about
"what is the most common failure case".

Currently, MMC drivers assume -ENOMEM is the best
fit for mmc_alloc_host(), but the assumption is fragile.

Already, mmc_alloc_host() calls a function
that returns not only -ENOMEM, but also -ENOSPC.

In the future, some other failure cases might be
added to mmc_alloc_host().

Once we decide the API returns an error pointer,
drivers just propagate the return value from the API.
This is much more stable implementation.



-- 
Best Regards
Masahiro Yamada

Re: [PATCH 0/2] mmc: allow mmc_alloc_host() and tmio_mmc_host_alloc()

[Greg Kroah-Hartman]

On Fri, Nov 11, 2016 at 12:19:05PM +0900, Masahiro Yamada wrote:
> 2016-11-10 22:35 GMT+09:00 Greg Kroah-Hartman <gregkh@linuxfoundation.org>:
> > On Thu, Nov 10, 2016 at 10:24:21PM +0900, Masahiro Yamada wrote:
> >>
> >> sdhci_alloc_host() returns an error pointer when it fails.
> >> but mmc_alloc_host() cannot.
> >>
> >> This series allow to propagate a proper error code
> >> when host-allocation fails.
> >
> > Why?  What can we really do about the error except give up?  Why does
> > having a explicit error value make any difference to the caller, they
> > can't do anything different, right?
> 
> 
> The error code is shown in the console, like
> 
>   probe of 5a000000.sdhc failed with error -12
> 
> 
> The proper error code will give a clue why the driver failed to probe.

Can't the mmc core show the reason once, and not require each and every
individual driver to show/say the same thing?  All a driver needs to
know is if it worked or didn't work.  Every time it didn't work, it
needs to unwind stuff and then recover properly.

The drivers do not do different things based on what type of error
happened, as they don't care at all.

So I strongly suggest leaving it simple, as it is today, as this makes
drivers simpler, they don't have to duplicate the same type of error
reporting all over the place, and it's easy to audit for.

It also makes it so that large patchsets that touch every driver like
this are not needed at all.

> > I suggest just leaving it as-is, it's simple, and you don't have to mess
> > with PTR_ERR() anywhere.
> 
> 
> Why?
> 
> Most of driver just give up probing for any error,
> but we still do ERR_PTR()/PTR_ERR() here and there.
> I think this patch is the same pattern.

I think we need to get rid of more of the ERR_PTR() stuff, as again,
it's useless.  All we need to know is an error happened, that's it.

> If a function returns NULL on failure, we need to think about
> "what is the most common failure case".
> 
> Currently, MMC drivers assume -ENOMEM is the best
> fit for mmc_alloc_host(), but the assumption is fragile.
> 
> Already, mmc_alloc_host() calls a function
> that returns not only -ENOMEM, but also -ENOSPC.
> 
> In the future, some other failure cases might be
> added to mmc_alloc_host().
> 
> Once we decide the API returns an error pointer,
> drivers just propagate the return value from the API.
> This is much more stable implementation.

Again, no, it makes more work for the different drivers, duplicates code
all over the place, and really doesn't help any user, or developer, out
at all.

Just have the mmc core properly log what went wrong, and all should be
fine.

Again, keep it simple, that's the best policy for the kernel, and
really, most software :)

thanks,

greg k-h