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<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968" /><title>bio_alloc</title><meta name="generator" content="DocBook XSL Stylesheets V1.75.2" /><link rel="home" href="index.html" title="Linux Filesystems API" /><link rel="up" href="ch01s06.html" title="Other Functions" /><link rel="prev" href="re90.html" title="bio_alloc_bioset" /><link rel="next" href="re92.html" title="bio_kmalloc" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center"><span>bio_alloc</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="re90.html">Prev</a> </td><th width="60%" align="center">Other Functions</th><td width="20%" align="right"> <a accesskey="n" href="re92.html">Next</a></td></tr></table><hr /></div><div class="refentry" title="bio_alloc"><a id="API-bio-alloc"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>bio_alloc —
allocate a new bio, memory pool backed
</p></div><div class="refsynopsisdiv" title="Synopsis"><h2>Synopsis</h2><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">struct bio * <b class="fsfunc">bio_alloc </b>(</code></td><td>gfp_t <var class="pdparam">gfp_mask</var>, </td></tr><tr><td> </td><td>int <var class="pdparam">nr_iovecs</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1" title="Arguments"><a id="id3015611"></a><h2>Arguments</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>gfp_mask</code></em></span></dt><dd><p>
allocation mask to use
</p></dd><dt><span class="term"><em class="parameter"><code>nr_iovecs</code></em></span></dt><dd><p>
number of iovecs
</p></dd></dl></div></div><div class="refsect1" title="Description"><a id="id3015653"></a><h2>Description</h2><p>
bio_alloc will allocate a bio and associated bio_vec array that can hold
at least <em class="parameter"><code>nr_iovecs</code></em> entries. Allocations will be done from the
fs_bio_set. Also see <em class="parameter"><code>bio_alloc_bioset</code></em> and <em class="parameter"><code>bio_kmalloc</code></em>.
</p><p>
If <code class="constant">__GFP_WAIT</code> is set, then bio_alloc will always be able to allocate
a bio. This is due to the mempool guarantees. To make this work, callers
must never allocate more than 1 bio at a time from this pool. Callers
that need to allocate more than 1 bio must always submit the previously
allocated bio for IO before attempting to allocate a new one. Failure to
do so can cause livelocks under memory pressure.
</p></div><div class="refsect1" title="RETURNS"><a id="id3015693"></a><h2>RETURNS</h2><p>
Pointer to new bio on success, NULL on failure.
</p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="re90.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="ch01s06.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="re92.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top"><span>bio_alloc_bioset</span> </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> <span>bio_kmalloc</span></td></tr></table></div></body></html>
