linux-kernel - [PATCH] [4/6] kfifo: add kfifo_out

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Sun, 27 Dec 2009 22:03:14 +0100 (CET)
From:	Andi Kleen <andi@...stfloor.org>
To:	stefani@...bold.net, linux-kernel@...r.kernel.org, akpm@...l.org
Subject: [PATCH] [4/6] kfifo: add kfifo_out_peek


In some upcoming code it's useful to peek into a FIFO without
permanentely removing data. This patch implements a new 
kfifo_out_peek() to do this. 

Signed-off-by: Andi Kleen <ak@...ux.intel.com>

---
 include/linux/kfifo.h |    3 +++
 kernel/kfifo.c        |   21 +++++++++++++++++++++
 2 files changed, 24 insertions(+)

Index: linux/include/linux/kfifo.h
===================================================================
--- linux.orig/include/linux/kfifo.h
+++ linux/include/linux/kfifo.h
@@ -114,6 +114,9 @@ extern unsigned int kfifo_in(struct kfif
 				const void *from, unsigned int len);
 extern __must_check unsigned int kfifo_out(struct kfifo *fifo,
 				void *to, unsigned int len);
+extern __must_check unsigned int kfifo_out_peek(struct kfifo *fifo,
+				void *to, unsigned int len, unsigned offset);
+
 
 /**
  * kfifo_reset - removes the entire FIFO contents
Index: linux/kernel/kfifo.c
===================================================================
--- linux.orig/kernel/kfifo.c
+++ linux/kernel/kfifo.c
@@ -301,6 +301,27 @@ unsigned int kfifo_out(struct kfifo *fif
 }
 EXPORT_SYMBOL(kfifo_out);
 
+/**
+ * kfifo_out_peek - copy some data from the FIFO, but do not remove it
+ * @fifo: the fifo to be used.
+ * @to: where the data must be copied.
+ * @len: the size of the destination buffer.
+ * @offset: offset into the fifo
+ *
+ * This function copies at most @len bytes at @offset from the FIFO
+ * into the @to buffer and returns the number of copied bytes.
+ * The data is not removed from the FIFO.
+ */
+unsigned int kfifo_out_peek(struct kfifo *fifo, void *to, unsigned int len,
+			    unsigned offset)
+{
+	len = min(kfifo_len(fifo), len + offset);
+
+	__kfifo_out_data(fifo, to, len, offset);
+	return len;
+}
+EXPORT_SYMBOL(kfifo_out_peek);
+
 unsigned int __kfifo_out_generic(struct kfifo *fifo,
 	void *to, unsigned int len, unsigned int recsize,
 	unsigned int *total)
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/