Messages in this thread | | | Date | Fri, 28 Dec 2012 18:48:25 +0400 | Subject | Re: [CRIU] [PATCH 1/4] signalfd: add ability to return siginfo in a raw format | From | Andrey Wagin <> |
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2012/12/28 Oleg Nesterov <oleg@redhat.com>: > On 12/28, Andrey Wagin wrote: >> >> 2012/12/28 Oleg Nesterov <oleg@redhat.com>: >> >> >> @@ -321,6 +372,7 @@ SYSCALL_DEFINE4(signalfd4, int, ufd, sigset_t __user *, user_mask, >> >> >> } >> >> >> >> >> >> file->f_flags |= flags & SFD_RAW; >> >> >> + file->f_mode |= FMODE_PREAD; >> >> >> >> >> >> fd_install(ufd, file); >> >> > >> >> > Hmm. Looks like it is based on other patches I didnt see... >> >> > >> >> > But I don't understand how FMODE_PREAD connects to this patch, we need >> >> > this flag set even for regular sys_read() ??? >> >> >> >> It doesn't need for sys_read(), but this patch is about pread() and >> >> sys_pread() checks it. >> >> >> >> SYSCALL_DEFINE(pread64)(unsigned int fd, char __user *buf, >> >> size_t count, loff_t pos) >> >> { >> >> .... >> >> if (f.file) { >> >> ret = -ESPIPE; >> >> if (f.file->f_mode & FMODE_PREAD) >> >> ret = vfs_read(f.file, buf, count, &pos); >> > >> > And sys_read() checks it too, that was my point. >> >> sys_read() doesn't check this flag. I tryed to remove this code from >> this patch and pread returned ESPIPE as expected. > > sys_read() calls vfs_read() which checks f_mode & FMODE_READ at the > start ?
FMODE_READ != FMODE_PREAD ;)
> > Oleg. >
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