• Leonid Iziumtsev's avatar
    dmaengine: imx-dma: fix wrong callback invoke · 341198ed
    Leonid Iziumtsev authored
    Once the "ld_queue" list is not empty, next descriptor will migrate
    into "ld_active" list. The "desc" variable will be overwritten
    during that transition. And later the dmaengine_desc_get_callback_invoke()
    will use it as an argument. As result we invoke wrong callback.
    
    That behaviour was in place since:
    commit fcaaba6c ("dmaengine: imx-dma: fix callback path in tasklet").
    But after commit 4cd13c21 ("softirq: Let ksoftirqd do its job")
    things got worse, since possible delay between tasklet_schedule()
    from DMA irq handler and actual tasklet function execution got bigger.
    And that gave more time for new DMA request to be submitted and
    to be put into "ld_queue" list.
    
    It has been noticed that DMA issue is causing problems for "mxc-mmc"
    driver. While stressing the system with heavy network traffic and
    writing/reading to/from sd card simultaneously the timeout may happen:
    
    10013000.sdhci: mxcmci_watchdog: read time out (status = 0x30004900)
    
    That often lead to file system corruption.
    Signed-off-by: default avatarLeonid Iziumtsev <leonid.iziumtsev@gmail.com>
    Signed-off-by: default avatarVinod Koul <vkoul@kernel.org>
    Cc: stable@vger.kernel.org
    341198ed
imx-dma.c 34.6 KB