>From 242fae6293adec671b14354f215217354f5076a0 Mon Sep 17 00:00:00 2001 From: Adrian Hunter <[email protected]> Date: Sat, 16 May 2009 10:32:34 +0300 Subject: [PATCH] omap_hsmmc: prevent races with irq handler
If an unexpected interrupt occurs while preparing the next request, an oops can occur. For example, a new request is setting up DMA for data transfer so host->data is not NULL. An unexpected transfer complete (TC) interrupt comes along and the interrupt handler sets host->data to NULL. Oops! Prevent that by disabling interrupts while setting up a new request. Signed-off-by: Adrian Hunter <[email protected]> --- drivers/mmc/host/omap_hsmmc.c | 16 ++++++++++++++++ 1 files changed, 16 insertions(+), 0 deletions(-) diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c index 28563d6..38e1410 100644 --- a/drivers/mmc/host/omap_hsmmc.c +++ b/drivers/mmc/host/omap_hsmmc.c @@ -452,6 +452,13 @@ mmc_omap_start_command(struct mmc_omap_host *host, struct mmc_command *cmd, if (host->use_dma) cmdreg |= DMA_EN; + /* + * In an interrupt context (i.e. STOP command), the interrupt is already + * enabled, otherwise it is not (i.e. new request). + */ + if (!in_interrupt()) + enable_irq(host->irq); + OMAP_HSMMC_WRITE(host->base, ARG, cmd->arg); OMAP_HSMMC_WRITE(host->base, CMD, cmdreg); } @@ -1011,6 +1018,13 @@ static void omap_mmc_request(struct mmc_host *mmc, struct mmc_request *req) struct mmc_omap_host *host = mmc_priv(mmc); int err; + /* + * Prevent races with the interrupt handler because of unexpected + * interrupts, but not if we are already in interrupt context i.e. + * retries. + */ + if (!in_interrupt()) + disable_irq(host->irq); WARN_ON(host->mrq != NULL); host->mrq = req; err = mmc_omap_prepare_data(host, req); @@ -1019,6 +1033,8 @@ static void omap_mmc_request(struct mmc_host *mmc, struct mmc_request *req) if (req->data) req->data->error = err; host->mrq = NULL; + if (!in_interrupt()) + enable_irq(host->irq); mmc_request_done(mmc, req); return; } -- 1.5.6.3 -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
