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authorAndrew Morton <akpm@osdl.org>2006-02-11 17:55:52 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-02-11 21:41:11 -0800
commit643a654540579b0dcc7a206a4a7475276a41aff0 (patch)
treee31d40e4362e4dc7823b7290c0de2a9353d3d117 /include/linux/compat.h
parent33042a9ff4d126ba944b9dc3076665a2029e0a34 (diff)
[PATCH] select: fix returned timeval
With David Woodhouse <dwmw2@infradead.org> select() presently has a habit of increasing the value of the user's `timeout' argument on return. We were writing back a timeout larger than the original. We _deliberately_ round up, since we know we must wait at _least_ as long as the caller asks us to. The patch adds a couple of helper functions for magnitude comparison of timespecs and of timevals, and uses them to prevent the various poll and select functions from returning a timeout which is larger than the one which was passed in. The patch also fixes a bug in compat_sys_pselect7(): it was adding the new timeout value to the old one and was returning that. It should just return the new timeout value. (We have various handy timespec/timeval-to-from-nsec conversion functions in time.h. But this code open-codes it all). Cc: "David S. Miller" <davem@davemloft.net> Cc: Andi Kleen <ak@muc.de> Cc: Ulrich Drepper <drepper@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: george anzinger <george@mvista.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include/linux/compat.h')
-rw-r--r--include/linux/compat.h20
1 files changed, 20 insertions, 0 deletions
diff --git a/include/linux/compat.h b/include/linux/compat.h
index f9ca534787e2..c9ab2a26348c 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -161,5 +161,25 @@ int copy_siginfo_to_user32(struct compat_siginfo __user *to, siginfo_t *from);
int get_compat_sigevent(struct sigevent *event,
const struct compat_sigevent __user *u_event);
+static inline int compat_timeval_compare(struct compat_timeval *lhs,
+ struct compat_timeval *rhs)
+{
+ if (lhs->tv_sec < rhs->tv_sec)
+ return -1;
+ if (lhs->tv_sec > rhs->tv_sec)
+ return 1;
+ return lhs->tv_usec - rhs->tv_usec;
+}
+
+static inline int compat_timespec_compare(struct compat_timespec *lhs,
+ struct compat_timespec *rhs)
+{
+ if (lhs->tv_sec < rhs->tv_sec)
+ return -1;
+ if (lhs->tv_sec > rhs->tv_sec)
+ return 1;
+ return lhs->tv_nsec - rhs->tv_nsec;
+}
+
#endif /* CONFIG_COMPAT */
#endif /* _LINUX_COMPAT_H */