'\" t
.\"     Title: blkdev_issue_zeroout
.\"    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: Block Devices
.\"    Source: Kernel Hackers Manual 4.8.15
.\"  Language: English
.\"
.TH "BLKDEV_ISSUE_ZEROOUT" "9" "January 2017" "Kernel Hackers Manual 4\&.8\&." "Block Devices"
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.SH "NAME"
blkdev_issue_zeroout \- zero\-fill a block range
.SH "SYNOPSIS"
.HP \w'int\ blkdev_issue_zeroout('u
.BI "int blkdev_issue_zeroout(struct\ block_device\ *\ " "bdev" ", sector_t\ " "sector" ", sector_t\ " "nr_sects" ", gfp_t\ " "gfp_mask" ", bool\ " "discard" ");"
.SH "ARGUMENTS"
.PP
\fIbdev\fR
.RS 4
blockdev to write
.RE
.PP
\fIsector\fR
.RS 4
start sector
.RE
.PP
\fInr_sects\fR
.RS 4
number of sectors to write
.RE
.PP
\fIgfp_mask\fR
.RS 4
memory allocation flags (for bio_alloc)
.RE
.PP
\fIdiscard\fR
.RS 4
whether to discard the block range
.RE
.SH "DESCRIPTION"
.PP
Zero\-fill a block range\&. If the discard flag is set and the block device guarantees that subsequent READ operations to the block range in question will return zeroes, the blocks will be discarded\&. Should the discard request fail, if the discard flag is not set, or if discard_zeroes_data is not supported, this function will resort to zeroing the blocks manually, thus provisioning (allocating, anchoring) them\&. If the block device supports the WRITE SAME command
\fBblkdev_issue_zeroout\fR
will use it to optimize the process of clearing the block range\&. Otherwise the zeroing will be performed using regular WRITE calls\&.
.SH "COPYRIGHT"
.br