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From f0e211453546a134ac27e1e54579332534acb349 Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Wed, 24 Jul 2024 14:05:14 -0700
Subject: [PATCH 09/12] mremap: Update manual entry
Update mremap manual entry:
1. Change mremap to variadic.
2. Document MREMAP_FIXED and MREMAP_DONTUNMAP.
Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
(cherry picked from commit cb2dee4eccf46642eef588bee64f9c875c408f1c)
---
manual/llio.texi | 42 +++++++++++++++++++++++++++++++++++-------
1 file changed, 35 insertions(+), 7 deletions(-)
diff --git a/manual/llio.texi b/manual/llio.texi
index fae49d1433..a65230d612 100644
--- a/manual/llio.texi
+++ b/manual/llio.texi
@@ -1781,7 +1781,7 @@ There is no existing mapping in at least part of the given region.
@end deftypefun
-@deftypefun {void *} mremap (void *@var{address}, size_t @var{length}, size_t @var{new_length}, int @var{flag})
+@deftypefun {void *} mremap (void *@var{address}, size_t @var{length}, size_t @var{new_length}, int @var{flag}, ... /* void *@var{new_address} */)
@standards{GNU, sys/mman.h}
@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}}
@@ -1790,12 +1790,40 @@ area. @var{address} and @var{length} must cover a region entirely mapped
in the same @code{mmap} statement. A new mapping with the same
characteristics will be returned with the length @var{new_length}.
-One option is possible, @code{MREMAP_MAYMOVE}. If it is given in
-@var{flags}, the system may remove the existing mapping and create a new
-one of the desired length in another location.
+Possible flags are
-The address of the resulting mapping is returned, or @math{-1}. Possible
-error codes include:
+@table @code
+
+@item MREMAP_MAYMOVE
+If it is given in @var{flags}, the system may remove the existing mapping
+and create a new one of the desired length in another location.
+
+@item MREMAP_FIXED
+If it is given in @var{flags}, @code{mremap} accepts a fifth argument,
+@code{void *new_address}, which specifies a page-aligned address to
+which the mapping must be moved. Any previous mapping at the address
+range specified by @var{new_address} and @var{new_size} is unmapped.
+
+@code{MREMAP_FIXED} must be used together with @code{MREMAP_MAYMOVE}.
+
+@item MREMAP_DONTUNMAP
+If it is given in @var{flags}, @code{mremap} accepts a fifth argument,
+@code{void *new_address}, which specifies a page-aligned address. Any
+previous mapping at the address range specified by @var{new_address} and
+@var{new_size} is unmapped. If @var{new_address} is @code{NULL}, the
+kernel chooses the page-aligned address at which to create the mapping.
+Otherwise, the kernel takes it as a hint about where to place the mapping.
+The mapping at the address range specified by @var{old_address} and
+@var{old_size} isn't unmapped.
+
+@code{MREMAP_DONTUNMAP} must be used together with @code{MREMAP_MAYMOVE}.
+@var{old_size} must be the same as @var{new_size}. This flag bit is
+Linux-specific.
+
+@end table
+
+The address of the resulting mapping is returned, or @code{MAP_FAILED}.
+Possible error codes include:
@table @code
@@ -1804,7 +1832,7 @@ There is no existing mapping in at least part of the original region, or
the region covers two or more distinct mappings.
@item EINVAL
-The address given is misaligned or inappropriate.
+Any arguments are inappropriate, including unknown @var{flags} values.
@item EAGAIN
The region has pages locked, and if extended it would exceed the
--
2.33.0
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