From 5988a659281eb354e7c427444fe4018ea59e32ad Mon Sep 17 00:00:00 2001
From: Michael Kerrisk <mtk.manpages@gmail.com>
Date: Sun, 24 May 2015 21:47:35 +0200
Subject: [PATCH] bpf.2: wfix (multiple)

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
---
 man2/bpf.2 | 41 ++++++++++++++++++++++-------------------
 1 file changed, 22 insertions(+), 19 deletions(-)

diff --git a/man2/bpf.2 b/man2/bpf.2
index 998f2deaa..ae0cb7288 100644
--- a/man2/bpf.2
+++ b/man2/bpf.2
@@ -32,8 +32,9 @@ bpf - perform a command on an extended BPF map or program
 .BI "int bpf(int cmd, union bpf_attr *attr, unsigned int size);
 
 .SH DESCRIPTION
+The
 .BR bpf()
-syscall is a multiplexor for a range of different operations on extended
+system call is a multiplexor for a range of different operations on extended
 Berkeley Packet Filter which can be characterized as
 "universal in-kernel virtual machine".
 The extended BPF (or eBPF) is similar to
@@ -86,9 +87,10 @@ event A     event B     event C     on eth0    on eth1
  map_1       map_2
 .fi
 .in
-.SS Syscall Arguments
+.SS Arguments
+The
 .BR bpf ()
-syscall operation is determined by
+system call operation is determined by
 .IR cmd
 which can be one of the following:
 .TP
@@ -96,16 +98,16 @@ which can be one of the following:
 Create a map with the given type and attributes and return map FD
 .TP
 .B BPF_MAP_LOOKUP_ELEM
-Lookup element by key in a given map and return its value
+Look up element by key in a given map and return its value
 .TP
 .B BPF_MAP_UPDATE_ELEM
 Create or update element (key/value pair) in a given map
 .TP
 .B BPF_MAP_DELETE_ELEM
-Lookup and delete element by key in a given map
+Look up and delete element by key in a given map
 .TP
 .B BPF_MAP_GET_NEXT_KEY
-Lookup element by key in a given map and return key of next element
+Look up element by key in a given map and return key of next element
 .TP
 .B BPF_PROG_LOAD
 Verify and load BPF program
@@ -160,8 +162,8 @@ Any map type has the following attributes:
   . key size in bytes
   . value size in bytes
 
-The following wrapper functions demonstrate how this syscall can be used to
-access the maps.
+The following wrapper functions demonstrate how this system
+call can be used to access the maps.
 The functions use the
 .IR cmd
 argument to invoke different operations.
@@ -182,14 +184,15 @@ int bpf_create_map(enum bpf_map_type map_type, int key_size,
 }
 .fi
 
+The
 .BR bpf ()
-syscall creates a map of
+system call creates a map of
 .I map_type
 type and given attributes
 .IR key_size ,
 .IR value_size ,
 .IR max_entries .
-On success it returns a process-local file descriptor.
+On success, it returns a process-local file descriptor.
 On error, \-1 is returned and
 .I errno
 is set to
@@ -285,14 +288,15 @@ int bpf_lookup_elem(int fd, void *key, void *value)
 }
 .fi
 
+The
 .BR bpf ()
-syscall looks up an element with a given
+system call looks up an element with a given
 .I key
 in a map
 .IR fd .
-If an element is found it returns zero and stores element's value into
+If an element is found, it returns zero and stores element's value into
 .I value.
-If no element is found it returns \-1 and sets
+If no element is found, it returns \-1 and sets
 .I errno
 to
 .BR ENOENT .
@@ -326,7 +330,7 @@ which can have one of 3 possible values:
 #define BPF_EXIST    2 /* update existing element */
 .fi
 
-On success it returns zero.
+On success, it returns zero.
 On error, \-1 is returned and
 .I errno
 is set to
@@ -374,7 +378,7 @@ The call deletes an element in a map
 with a given
 .IR key .
 Returns zero on success.
-If the element is not found it returns \-1 and sets
+If the element is not found, it returns \-1 and sets
 .I errno
 to
 .BR ENOENT .
@@ -678,8 +682,7 @@ is set appropriately.
 .SH ERRORS
 .TP
 .B EPERM
-.BR bpf()
-syscall was made without sufficient privilege
+The call was made without sufficient privilege
 (without the
 .B CAP_SYS_ADMIN
 capability).
@@ -740,7 +743,7 @@ This may be because it may have
 accessed a disallowed memory region or an uninitialized stack/register or
 because the function contraints don't match the actual types or because
 there was a misaligned memory access.
-In such case it is recommended to call
+In this case, it is recommended to call
 .BR bpf ()
 again with
 .I log_level = 1
@@ -767,5 +770,5 @@ These commands may be used only by a privileged process (one having the
 .B CAP_SYS_ADMIN
 capability).
 .SH SEE ALSO
-Both classic and extended BPF are explained in
+Both classic and extended BPF are explained in the kernel source file
 .IR Documentation/networking/filter.txt .