The patch titled
kfifo: make kfifo_in atomic
has been added to the -mm tree. Its filename is
kfifo-make-kfifo_in-atomic.patch
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Subject: kfifo: make kfifo_in atomic
From: Andi Kleen <andi@xxxxxxxxxxxxxx>
Right now kfifo_in allows copying in less than the input amount. This is
unfortunately not a good idea on any record oriented users: if the size of
the kfifo is not a multiple of the record (and that can easily happen due
to the power-of-two requirement) then when the FIFO fills up partial
records could be put in. Such a condition would be fatal for any record
consumer who would get permanently desynchronized. In fact I doubt unless
the input is a totally boundary less data stream I doubt anything could
handle this.
Change kfifo_in() to always put in everything or nothing.
The return value is now always 0 or the full length.
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Stefani Seibold <stefani@xxxxxxxxxxx>
Cc: Roland Dreier <rdreier@xxxxxxxxx>
Cc: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
Cc: Andy Walls <awalls@xxxxxxxxx>
Cc: Vikram Dhillon <dhillonv10@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/kfifo.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff -puN kernel/kfifo.c~kfifo-make-kfifo_in-atomic kernel/kfifo.c
--- a/kernel/kfifo.c~kfifo-make-kfifo_in-atomic
+++ a/kernel/kfifo.c
@@ -228,9 +228,8 @@ EXPORT_SYMBOL(__kfifo_in_n);
* @from: the data to be added.
* @len: the length of the data to be added.
*
- * This function copies at most @len bytes from the @from buffer into
- * the FIFO depending on the free space, and returns the number of
- * bytes copied.
+ * This function copies @len bytes from the @from buffer into
+ * the FIFO and returns 0 if there is not enough space.
*
* Note that with only one concurrent reader and one concurrent
* writer, you don't need extra locking to use these functions.
@@ -238,8 +237,8 @@ EXPORT_SYMBOL(__kfifo_in_n);
unsigned int kfifo_in(struct kfifo *fifo, const void *from,
unsigned int len)
{
- len = min(kfifo_avail(fifo), len);
-
+ if (kfifo_avail(fifo) < len)
+ return 0;
__kfifo_in_data(fifo, from, len, 0);
__kfifo_add_in(fifo, len);
return len;
_
Patches currently in -mm which might be from andi@xxxxxxxxxxxxxx are
origin.patch
kernel-signalc-fix-kernel-information-leak-with-print-fatal-signals=1.patch
kfifo-use-void-pointers-for-user-buffers.patch
kfifo-make-kfifo_in-atomic.patch
kfifo-sanitize-_user-error-handling.patch
kfifo-add-kfifo_out_peek.patch
kfifo-add-kfifo_initialized.patch
kfifo-document-everywhere-that-size-has-to-be-power-of-two.patch
hardware-latency-detector-remove-default-m.patch
kbuild-move-fno-dwarf2-cfi-asm-to-powerpc-only.patch
mm-introduce-dump_page-and-print-symbolic-flag-names.patch
tracehooks-kill-some-pt_ptraced-checks.patch
tracehooks-check-pt_ptraced-before-reporting-the-single-step.patch
ptrace_signal-check-pt_ptraced-before-reporting-a-signal.patch
export-__ptrace_detach-and-do_notify_parent_cldstop.patch
reorder-the-code-in-kernel-ptracec.patch
implement-utrace-ptrace.patch
utrace-core.patch
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