'\" t
.\"     Title: ll_rw_block
.\"    Author: [FIXME: author] [see http://docbook.sf.net/el/author]
.\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
.\"      Date: January 2017
.\"    Manual: The Linux VFS
.\"    Source: Kernel Hackers Manual 4.8.15
.\"  Language: English
.\"
.TH "LL_RW_BLOCK" "9" "January 2017" "Kernel Hackers Manual 4\&.8\&." "The Linux VFS"
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.SH "NAME"
ll_rw_block \- level access to block devices (DEPRECATED)
.SH "SYNOPSIS"
.HP \w'void\ ll_rw_block('u
.BI "void ll_rw_block(int\ " "op" ", int\ " "op_flags" ", int\ " "nr" ", struct\ buffer_head\ *\ " "bhs[]" ");"
.SH "ARGUMENTS"
.PP
\fIop\fR
.RS 4
whether to
\fBREAD\fR
or
\fBWRITE\fR
.RE
.PP
\fIop_flags\fR
.RS 4
rq_flag_bits
.RE
.PP
\fInr\fR
.RS 4
number of
struct buffer_heads
in the array
.RE
.PP
\fIbhs[]\fR
.RS 4
array of pointers to
struct buffer_head
.RE
.SH "DESCRIPTION"
.PP
\fBll_rw_block\fR
takes an array of pointers to
struct buffer_heads, and requests an I/O operation on them, either a
\fBREQ_OP_READ\fR
or a
\fBREQ_OP_WRITE\fR\&.
\fIop_flags\fR
contains flags modifying the detailed I/O behavior, most notably
\fBREQ_RAHEAD\fR\&.
.PP
This function drops any buffer that it cannot get a lock on (with the BH_Lock state bit), any buffer that appears to be clean when doing a write request, and any buffer that appears to be up\-to\-date when doing read request\&. Further it marks as clean buffers that are processed for writing (the buffer cache won\*(Aqt assume that they are actually clean until the buffer gets unlocked)\&.
.PP
ll_rw_block sets b_end_io to simple completion handler that marks the buffer up\-to\-date (if appropriate), unlocks the buffer and wakes any waiters\&.
.PP
All of the buffers must be for the same device, and must also be a multiple of the current approved size for the device\&.
.SH "COPYRIGHT"
.br