From 94538e51d67da97e798d379d6bcf3d386d609bfb Mon Sep 17 00:00:00 2001 From: Russell King Date: Tue, 26 Jan 2016 13:40:37 +0000 Subject: [PATCH] mmc: sdhci: clean up host cookie handling Commit d31911b9374a ("mmc: sdhci: fix dma memory leak in sdhci_pre_req()") added a complicated method to manage the DMA map state for the data transfer, but this complexity is not required. There are three states: * Unmapped * Mapped by sdhci_pre_req() * Mapped by sdhci_prepare_data() sdhci_prepare_data() needs to know when the data buffers have been successfully mapped by sdhci_pre_req(), and if so, there is no need to map them a second time. When we come to tear down the mapping, we want to know whether sdhci_post_req() will be called (which is determined by sdhci_pre_req() having been previously called) so that we can postpone the unmap operation. Hence, it makes sense to simply record when the successful DMA map happened (via COOKIE_PRE_MAPPED vs COOKIE_MAPPED) rather than having the complex mechanics involving COOKIE_MAPPED vs COOKIE_GIVEN. If a mapping is created by sdhci_prepare_data(), we must tear it down ourselves, without waiting for sdhci_post_req() (hence, the new COOKIE_MAPPED case). If the mapping is created by sdhci_pre_req() then sdhci_post_req() is responsible for tearing the mapping down. Signed-off-by: Russell King Signed-off-by: Adrian Hunter Tested-by: Gregory CLEMENT Signed-off-by: Ulf Hansson --- drivers/mmc/host/sdhci.c | 12 ++++++------ drivers/mmc/host/sdhci.h | 4 ++-- 2 files changed, 8 insertions(+), 8 deletions(-) diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index 393a1b077746..16e8db00fc49 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -431,12 +431,12 @@ static int sdhci_pre_dma_transfer(struct sdhci_host *host, { int sg_count; - if (data->host_cookie == COOKIE_MAPPED) { - data->host_cookie = COOKIE_GIVEN; + /* + * If the data buffers are already mapped, return the previous + * dma_map_sg() result. + */ + if (data->host_cookie == COOKIE_PRE_MAPPED) return data->sg_count; - } - - WARN_ON(data->host_cookie == COOKIE_GIVEN); sg_count = dma_map_sg(mmc_dev(host->mmc), data->sg, data->sg_len, data->flags & MMC_DATA_WRITE ? @@ -2094,7 +2094,7 @@ static void sdhci_pre_req(struct mmc_host *mmc, struct mmc_request *mrq, mrq->data->host_cookie = COOKIE_UNMAPPED; if (host->flags & SDHCI_REQ_USE_DMA) - sdhci_pre_dma_transfer(host, mrq->data, COOKIE_MAPPED); + sdhci_pre_dma_transfer(host, mrq->data, COOKIE_PRE_MAPPED); } static void sdhci_card_event(struct mmc_host *mmc) diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h index 0115e9907bf8..3bd28033dbd9 100644 --- a/drivers/mmc/host/sdhci.h +++ b/drivers/mmc/host/sdhci.h @@ -316,8 +316,8 @@ struct sdhci_adma2_64_desc { enum sdhci_cookie { COOKIE_UNMAPPED, - COOKIE_MAPPED, - COOKIE_GIVEN, + COOKIE_PRE_MAPPED, /* mapped by sdhci_pre_req() */ + COOKIE_MAPPED, /* mapped by sdhci_prepare_data() */ }; struct sdhci_host {