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dmaengine: device must have at least one channel 

The DMA device can't be registered if it doesn't have any channels
registered at all. Moreover, it leads to memory leak and is reported by
kmemleak as (on 3.10 kernel, and same shall happen on mainline):

unreferenced object 0xffffffc09e597240 (size 64):
  comm "swapper/0", pid 1, jiffies 4294877736 (age 7060.280s)
  hex dump (first 32 bytes):
    00 00 00 00 c0 ff ff ff 30 00 00 ff 00 00 00 ff  ........0.......
    00 00 00 ff 00 00 00 ff 00 00 00 ff 00 00 00 ff  ................
  backtrace:
    [<ffffffc0003079ec>] create_object+0x148/0x2a0
    [<ffffffc000cc150c>] kmemleak_alloc+0x80/0xbc
    [<ffffffc000303a7c>] kmem_cache_alloc_trace+0x120/0x1ac
    [<ffffffc00054771c>] dma_async_device_register+0x160/0x46c
    [<ffffffc000548958>] foo_probe+0x1a0/0x264
    [<ffffffc0005d6658>] platform_drv_probe+0x14/0x20
    [<ffffffc0005d50cc>] driver_probe_device+0x160/0x374
    [<ffffffc0005d538c>] __driver_attach+0x60/0x90
    [<ffffffc0005d3e78>] bus_for_each_dev+0x7c/0xb0
    [<ffffffc0005d4a0c>] driver_attach+0x1c/0x28
    [<ffffffc0005d459c>] bus_add_driver+0x124/0x248
    [<ffffffc0005d59cc>] driver_register+0x90/0x110
    [<ffffffc0005d6bf4>] platform_driver_register+0x58/0x64
    [<ffffffc00142a70c>] foo_driver_init+0x10/0x1c
    [<ffffffc000200878>] do_one_initcall+0xac/0x148
    [<ffffffc00140096c>] kernel_init_freeable+0x1a0/0x258

Return -ENODEV from dma_async_device_register() on such a case.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
steinar/wifi_calib_4_9_kernel
Viresh Kumar 2016-07-27 14:32:58 -07:00 committed by Vinod Koul
parent 29b4817d40
commit 76d7b84bfa
1 changed files with 7 additions and 0 deletions
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7
drivers/dma/dmaengine.c
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@ -997,6 +997,13 @@ int dma_async_device_register(struct dma_device *device)
}
chan->client_count = 0;
}
if (!chancnt) {
dev_err(device->dev, "%s: device has no channels!\n", __func__);
rc = -ENODEV;
goto err_out;
}
device->chancnt = chancnt;
mutex_lock(&dma_list_mutex);