Messages in this thread | | | Subject | Re: [PATCH] staging: android: ashmem: lseek failed due to no FMODE_LSEEK. | From | Greg Hackmann <> | Date | Thu, 6 Apr 2017 10:25:32 -0700 |
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On 04/06/2017 10:08 AM, Greg KH wrote: > On Thu, Apr 06, 2017 at 08:30:40AM -0700, Greg Hackmann wrote: >> On 04/06/2017 07:30 AM, zhangshuxiaomi@gmail.com wrote: >>> From: zhangshuxiao <zhangshuxiao@xiaomi.com> >>> >>> vfs_llseek will check whether the file mode has >>> FMODE_LSEEK, no return failure. But ashmem can be >>> lseek, so add FMODE_LSEEK to ashmem file. >>> >>> Signed-off-by: Shuxiao Zhang <zhangshuxiao@xiaomi.com> >>> Tested-by: Greg Hackmann <ghackmann@google.com> >>> --- >>> drivers/staging/android/ashmem.c | 1 + >>> 1 file changed, 1 insertion(+) >>> >>> diff --git a/drivers/staging/android/ashmem.c b/drivers/staging/android/ashmem.c >>> index 3f11332..e4530ac 100644 >>> --- a/drivers/staging/android/ashmem.c >>> +++ b/drivers/staging/android/ashmem.c >>> @@ -392,6 +392,7 @@ static int ashmem_mmap(struct file *file, struct vm_area_struct *vma) >>> ret = PTR_ERR(vmfile); >>> goto out; >>> } >>> + vmfile->f_mode |= FMODE_LSEEK; >>> asma->file = vmfile; >>> } >>> get_file(asma->file); >>> >> >> This commit message is missing some important context. >> >> ashmem_llseek() passes the llseek() call through to the backing shmem file. >> 91360b02ab48 ("ashmem: use vfs_llseek()") changed this from directly calling >> the file's llseek() op into a VFS layer call. This also adds a check for >> the FMODE_LSEEK bit, so without that bit ashmem_llseek() now always fails >> with -ESPIPE. >> >> I've tested that this patch fixes the regression on both hikey running AOSP >> and User Mode Linux running Debian. > > Thanks for letting me know, I'll update the changelog a bit. How far > back does this patch need to go in stable kernel releases? > > thanks, > > greg k-h >
3.18 and later.
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