Hi Christian,
On 2017-02-21 14:59, Christian König wrote:
Am 21.02.2017 um 14:21 schrieb Marek Szyprowski:
Add compat ioctl support to dma-buf. This lets one to use DMA_BUF_IOCTL_SYNC ioctl from 32bit application on 64bit kernel. Data structures for both 32 and 64bit modes are same, so there is no need for additional translation layer.
Well I might be wrong, but IIRC compat_ioctl was just optional and if not specified unlocked_ioctl was called instead.
If that is true your patch wouldn't have any effect at all.
Well, then why I got -ENOTTY in the 32bit test app for this ioctl on 64bit ARM64 kernel without this patch?
Best regards
Dear All,
On 2017-02-21 15:37, Marek Szyprowski wrote:
Hi Christian,
On 2017-02-21 14:59, Christian König wrote:
Am 21.02.2017 um 14:21 schrieb Marek Szyprowski:
Add compat ioctl support to dma-buf. This lets one to use DMA_BUF_IOCTL_SYNC ioctl from 32bit application on 64bit kernel. Data structures for both 32 and 64bit modes are same, so there is no need for additional translation layer.
Well I might be wrong, but IIRC compat_ioctl was just optional and if not specified unlocked_ioctl was called instead.
If that is true your patch wouldn't have any effect at all.
Well, then why I got -ENOTTY in the 32bit test app for this ioctl on 64bit ARM64 kernel without this patch?
I've checked in fs/compat_ioctl.c, I see no fallback in COMPAT_SYSCALL_DEFINE3, so one has to provide compat_ioctl callback to have ioctl working with 32bit apps.
Best regards
linaro-mm-sig@lists.linaro.org
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Marek Szyprowski