bpf.2: srcfix: wrap source lines at sentence breaks

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

man2/bpf.2

@@ -35,9 +35,10 @@ bpf - perform a command on an extended BPF map or program
 .BR bpf()
 syscall 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
-the original BPF (or classic BPF) used to filter network packets. Both
-statically analyze the programs before loading them into the kernel to
+"universal in-kernel virtual machine".
+The extended BPF (or eBPF) is similar to
+the original BPF (or classic BPF) used to filter network packets.
+Both statically analyze the programs before loading them into the kernel to
 ensure that they cannot harm the running system.
 .P
 eBPF extends classic BPF in multiple ways including the ability to call
@@ -54,15 +55,19 @@ BPF programs can access maps from inside the kernel in parallel.
 It's up to the user process and BPF program to decide what they store
 inside maps.
 .P
-BPF programs are similar to kernel modules. They are loaded by the user
+BPF programs are similar to kernel modules.
+They are loaded by the user
 process and automatically unloaded when the process exits.
 Each BPF program is a set of instructions that is safe to run until
-its completion. The BPF verifier statically determines that the program
-terminates and is safe to execute. During
-verification the program takes hold of maps that it intends to use,
-so selected maps cannot be removed until the program is unloaded. The program
-can be attached to different events. These events can be packets, tracing
-events and other types that may be added in the future. A new event triggers
+its completion.
+The BPF verifier statically determines that the program
+terminates and is safe to execute.
+During verification the program takes hold of maps that it intends to use,
+so selected maps cannot be removed until the program is unloaded.
+The program can be attached to different events.
+These events can be packets, tracing
+events and other types that may be added in the future.
+A new event triggers
 execution of the program which may store information about the event in the maps.
 Beyond storing data the programs may call into in-kernel helper functions.
 The same program can be attached to multiple events and different programs can
@@ -149,7 +154,8 @@ Any map type has the following attributes:
   . value size in bytes
 
 The following wrapper functions demonstrate how this syscall can be used to
-access the maps. The functions use the
+access the maps.
+The functions use the
 .IR cmd
 argument to invoke different operations.
 .TP
@@ -172,7 +178,8 @@ bpf() syscall creates a map of
 .I map_type
 type and given attributes
 .I key_size, value_size, max_entries.
-On success it returns a process-local file descriptor. On error, \-1 is returned and
+On success it returns a process-local file descriptor.
+On error, \-1 is returned and
 .I errno
 is set to EINVAL or EPERM or ENOMEM.
 
@@ -216,7 +223,8 @@ enum bpf_map_type {
 };
 .fi
 .I map_type
-selects one of the available map implementations in the kernel. For all map_types
+selects one of the available map implementations in the kernel.
+For all map_types
 programs access maps with the same bpf_map_lookup_elem()/bpf_map_update_elem()
 helper functions.
 .TP
@@ -300,7 +308,8 @@ The call deletes an element in a map
 .I fd
 with a given
 .I key.
-Returns zero on success. If the element is not found it returns \-1 and sets
+Returns zero on success.
+If the element is not found it returns \-1 and sets
 .I errno
 to ENOENT.
 .TP
@@ -333,7 +342,8 @@ If
 .I key
 is the last element, it returns \-1 and sets
 .I errno
-to ENOENT. Other possible
+to ENOENT.
+Other possible
 .I errno
 values are ENOMEM, EFAULT, EPERM and EINVAL.
 This method can be used to iterate over all elements in the map.
@@ -404,10 +414,11 @@ bpf_map_update_elem(map_fd, void *key, void *value) // update key/value
 bpf_map_delete_elem(map_fd, void *key)              // delete key in a map_fd
 .fi
 
-and bpf_context is a pointer to 'struct sk_buff'. Programs cannot
-access fields of 'sk_buff' directly.
+and bpf_context is a pointer to 'struct sk_buff'.
+Programs cannot access fields of 'sk_buff' directly.
 
-More program types may be added in the future. Like
+More program types may be added in the future.
+Like
 .B BPF_PROG_TYPE_KPROBE
 and bpf_context for it may be defined as a pointer to 'struct pt_regs'.
 
@@ -423,19 +434,22 @@ marked gpl_only.
 
 .B log_buf
 user supplied buffer that the in-kernel verifier is using to store the
-verification log. This log is a multi-line string that can be checked by
+verification log.
+This log is a multi-line string that can be checked by
 the program author in order to understand how the verifier came to
 the conclusion that the BPF program is unsafe.
 The format of the output can change at any time as the verifier evolves.
 
 .B log_size
-size of user buffer. If the size of the buffer is not large enough to store all
+size of user buffer.
+If the size of the buffer is not large enough to store all
 verifier messages, \-1 is returned and
 .I errno
 is set to ENOSPC.
 
 .B log_level
-verbosity level of the verifier. A value of zero means that the verifier will
+verbosity level of the verifier.
+A value of zero means that the verifier will
 not provide a log.
 
 .TP
@@ -445,13 +459,16 @@ will unload the BPF program.
 The maps are accessible from programs and used to exchange data between
 programs and between them and user space.
 Programs process various events (like kprobe, packets) and
-store their data into maps. User space fetches data from the maps.
+store their data into maps.
+User space fetches data from the maps.
 Either the same or a different map may be used by user space as a configuration
 space to alter program behavior on the fly.
 .SS Events
 .P
-Once a program is loaded, it can be attached to an event. Various kernel
-subsystems have different ways to do so. For example:
+Once a program is loaded, it can be attached to an event.
+Various kernel
+subsystems have different ways to do so.
+For example:
 
 .nf
 setsockopt(sock, SOL_SOCKET, SO_ATTACH_BPF, &prog_fd, sizeof(prog_fd));
@@ -590,7 +607,8 @@ are not set to zero.
 .B EINVAL
 For
 .BR BPF_PROG_LOAD,
-indicates an attempt to load an invalid program. BPF programs can be deemed
+indicates an attempt to load an invalid program.
+BPF programs can be deemed
 invalid due to unrecognized instructions, the use of reserved fields, jumps
 out of range, infinite loops or calls of unknown functions.
 .TP
@@ -598,7 +616,8 @@ out of range, infinite loops or calls of unknown functions.
 For
 .BR BPF_PROG_LOAD,
 even though all program instructions are valid, the program has been
-rejected because it was deemed unsafe. This may be because it may have
+rejected because it was deemed unsafe.
+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.