Messages in this thread | | | Subject | Can we drop __must_check from driver_for_each_device()? | From | Paul Bolle <> | Date | Wed, 31 Jul 2013 23:35:13 +0200 |
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Greg,
0) Summary: I think __must_check can be dropped from driver_for_each_device(). Do you agree?
1) Commit 4a7fb6363f ("add __must_check to device management code") added __must_check to driver_for_each_device(), seven years ago. But of the seventeen current users of that function just one actually seems to care about its return value:
- dead code: drivers/mtd/onenand/omap2.c:omap2_onenand_rephase()
- callback always returns zero: drivers/infiniband/hw/qib/qib_init.c:qib_notify_dca() (see all three possible values of f_notify_dca()) drivers/media/pci/cx25821/cx25821-alsa.c:cx25821_audio_fini() drivers/media/pci/cx25821/cx25821-alsa.c:cx25821_alsa_init() drivers/net/can/usb/peak_usb/pcan_usb_core.c:peak_usb_exit() drivers/net/ethernet/intel/igb/igb_main.c:igb_notify_dca() drivers/net/ethernet/intel/ixgbe/ixgbe_main.c:ixgbe_notify_dca() drivers/net/ethernet/myricom/myri10ge/myri10ge.c:myri10ge_notify_dca()
- return value of callback ignored: drivers/iommu/omap-iommu.c:omap_foreach_iommu_device() (when called by iommu_debugfs_exit()) drivers/isdn/hardware/mISDN/hfcpci.c:hfcpci_softirq() drivers/media/pci/cx18/cx18-alsa-main.c:cx18_alsa_exit() drivers/media/pci/ivtv/ivtv-alsa-main.c:ivtv_alsa_exit() drivers/media/pci/ivtv/ivtvfb.c:ivtvfb_init() drivers/media/pci/ivtv/ivtvfb.c:ivtvfb_cleanup() drivers/media/platform/s5p-tv/mixer_video.c:find_and_register_subdev() drivers/net/wireless/brcm80211/brcmfmac/usb.c:brcmf_usb_exit()
- return value actually used: drivers/iommu/omap-iommu.c:omap_foreach_iommu_device() (when called by iommu_debug_init())
2) Please note that if the callback always returns zero, driver_for_each_device() can still return -EINVAL, but only if it was provided a NULL "drv" (a struct device_driver). It sure seems odd to do so. Can that actually happen?
3) So to me it looks the __must_check attribute of driver_for_each_device() can be dropped. Do you agree?
Paul Bolle
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