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>
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 393a1b0..16e8db0 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -431,12 +431,12 @@
{
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 @@
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)