svn commit: r311963 - head/sys/kern
Ravi Pokala
rpokala at FreeBSD.org
Thu Jan 12 06:38:04 UTC 2017
Author: rpokala
Date: Thu Jan 12 06:38:03 2017
New Revision: 311963
URL: https://svnweb.freebsd.org/changeset/base/311963
Log:
Remove writability requirement for single-mbuf, contiguous-range
m_pulldown()
m_pulldown() only needs to determine if a mbuf is writable if it is going to
copy data into the data region of an existing mbuf. It does this to create a
contiguous data region in a single mbuf from multiple mbufs in the chain. If
the requested memory region is already contiguous and nothing needs to
change, the mbuf does not need to be writeable.
Submitted by: Brian Mueller <bmueller at panasas.com>
Reviewed by: bz
MFC after: 1 week
Sponsored by: Panasas
Differential Revision: https://reviews.freebsd.org/D9053
Modified:
head/sys/kern/uipc_mbuf2.c
Modified: head/sys/kern/uipc_mbuf2.c
==============================================================================
--- head/sys/kern/uipc_mbuf2.c Thu Jan 12 06:30:44 2017 (r311962)
+++ head/sys/kern/uipc_mbuf2.c Thu Jan 12 06:38:03 2017 (r311963)
@@ -159,7 +159,7 @@ m_pulldown(struct mbuf *m, int off, int
* the target data is on <n, off>.
* if we got enough data on the mbuf "n", we're done.
*/
- if ((off == 0 || offp) && len <= n->m_len - off && writable)
+ if ((off == 0 || offp) && len <= n->m_len - off)
goto ok;
/*
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