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| author | Russell King | 2016-01-26 14:40:37 +0100 |
|---|---|---|
| committer | Ulf Hansson | 2016-02-29 11:03:22 +0100 |
| commit | 94538e51d67da97e798d379d6bcf3d386d609bfb (patch) | |
| tree | 5c78bf6836b36b206a89a23171566f92ea988dac /drivers/mmc/host/sdhci.c | |
| parent | mmc: sdhci: always unmap a mapped data transfer in sdhci_post_req() (diff) | |
| download | kernel-qcow2-linux-94538e51d67da97e798d379d6bcf3d386d609bfb.tar.gz kernel-qcow2-linux-94538e51d67da97e798d379d6bcf3d386d609bfb.tar.xz kernel-qcow2-linux-94538e51d67da97e798d379d6bcf3d386d609bfb.zip | |
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 <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Diffstat (limited to 'drivers/mmc/host/sdhci.c')
| -rw-r--r-- | drivers/mmc/host/sdhci.c | 12 |
1 files changed, 6 insertions, 6 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) |