preadv2() was introduced in Linux 4.6. This patch adds support for
preadv2() to xfs_io.
Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@xxxxxxxxx>
---
configure.ac | 1 +
include/builddefs.in | 1 +
io/Makefile | 4 ++++
io/pread.c | 45 ++++++++++++++++++++++++++++---------------
m4/package_libcdev.m4 | 18 +++++++++++++++++
5 files changed, 54 insertions(+), 15 deletions(-)
diff --git a/configure.ac b/configure.ac
index 8c76f398..658117ad 100644
--- a/configure.ac
+++ b/configure.ac
@@ -153,6 +153,7 @@ AC_PACKAGE_NEED_URCU_H
AC_PACKAGE_NEED_RCU_INIT
AC_HAVE_PWRITEV2
+AC_HAVE_PREADV2
AC_HAVE_COPY_FILE_RANGE
AC_NEED_INTERNAL_FSXATTR
AC_NEED_INTERNAL_FSCRYPT_ADD_KEY_ARG
diff --git a/include/builddefs.in b/include/builddefs.in
index 82840ec7..a11d201c 100644
--- a/include/builddefs.in
+++ b/include/builddefs.in
@@ -94,6 +94,7 @@ ENABLE_SCRUB = @enable_scrub@
HAVE_ZIPPED_MANPAGES = @have_zipped_manpages@
HAVE_PWRITEV2 = @have_pwritev2@
+HAVE_PREADV2 = @have_preadv2@
HAVE_COPY_FILE_RANGE = @have_copy_file_range@
NEED_INTERNAL_FSXATTR = @need_internal_fsxattr@
NEED_INTERNAL_FSCRYPT_ADD_KEY_ARG = @need_internal_fscrypt_add_key_arg@
diff --git a/io/Makefile b/io/Makefile
index 8f835ec7..f8b19ac5 100644
--- a/io/Makefile
+++ b/io/Makefile
@@ -69,6 +69,10 @@ ifeq ($(HAVE_PWRITEV2),yes)
LCFLAGS += -DHAVE_PWRITEV2
endif
+ifeq ($(HAVE_PREADV2),yes)
+LCFLAGS += -DHAVE_PREADV2
+endif
+
ifeq ($(HAVE_MAP_SYNC),yes)
LCFLAGS += -DHAVE_MAP_SYNC
endif
diff --git a/io/pread.c b/io/pread.c
index 62c771fb..782f2a36 100644
--- a/io/pread.c
+++ b/io/pread.c
@@ -162,7 +162,8 @@ static ssize_t
do_preadv(
int fd,
off_t offset,
- long long count)
+ long long count,
+ int preadv2_flags)
{
int vecs = 0;
ssize_t oldlen = 0;
@@ -181,8 +182,14 @@ do_preadv(
} else {
vecs = vectors;
}
+#ifdef HAVE_PREADV2
+ if (preadv2_flags)
+ bytes = preadv2(fd, iov, vectors, offset, preadv2_flags);
+ else
+ bytes = preadv(fd, iov, vectors, offset);
+#else
bytes = preadv(fd, iov, vectors, offset);
-
+#endif
/* restore trimmed iov */
if (oldlen)
iov[vecs - 1].iov_len = oldlen;
@@ -195,12 +202,13 @@ do_pread(
int fd,
off_t offset,
long long count,
- size_t buffer_size)
+ size_t buffer_size,
+ int preadv2_flags)
{
if (!vectors)
return pread(fd, io_buffer, min(count, buffer_size), offset);
- return do_preadv(fd, offset, count);
+ return do_preadv(fd, offset, count, preadv2_flags);
}
static int
@@ -210,7 +218,8 @@ read_random(
long long count,
long long *total,
unsigned int seed,
- int eof)
+ int eof,
+ int preadv2_flags)
{
off_t end, off, range;
ssize_t bytes;
@@ -234,7 +243,7 @@ read_random(
io_buffersize;
else
off = offset;
- bytes = do_pread(fd, off, io_buffersize, io_buffersize);
+ bytes = do_pread(fd, off, io_buffersize, io_buffersize, preadv2_flags);
if (bytes == 0)
break;
if (bytes < 0) {
@@ -256,7 +265,8 @@ read_backward(
off_t *offset,
long long *count,
long long *total,
- int eof)
+ int eof,
+ int preadv2_flags)
{
off_t end, off = *offset;
ssize_t bytes = 0, bytes_requested;
@@ -276,7 +286,7 @@ read_backward(
/* Do initial unaligned read if needed */
if ((bytes_requested = (off % io_buffersize))) {
off -= bytes_requested;
- bytes = do_pread(fd, off, bytes_requested, io_buffersize);
+ bytes = do_pread(fd, off, bytes_requested, io_buffersize, preadv2_flags);
if (bytes == 0)
return ops;
if (bytes < 0) {
@@ -294,7 +304,7 @@ read_backward(
while (cnt > end) {
bytes_requested = min(cnt, io_buffersize);
off -= bytes_requested;
- bytes = do_pread(fd, off, cnt, io_buffersize);
+ bytes = do_pread(fd, off, cnt, io_buffersize, preadv2_flags);
if (bytes == 0)
break;
if (bytes < 0) {
@@ -318,14 +328,15 @@ read_forward(
long long *total,
int verbose,
int onlyone,
- int eof)
+ int eof,
+ int preadv2_flags)
{
ssize_t bytes;
int ops = 0;
*total = 0;
while (count > 0 || eof) {
- bytes = do_pread(fd, offset, count, io_buffersize);
+ bytes = do_pread(fd, offset, count, io_buffersize, preadv2_flags);
if (bytes == 0)
break;
if (bytes < 0) {
@@ -353,7 +364,7 @@ read_buffer(
int verbose,
int onlyone)
{
- return read_forward(fd, offset, count, total, verbose, onlyone, 0);
+ return read_forward(fd, offset, count, total, verbose, onlyone, 0, 0);
}
static int
@@ -371,6 +382,7 @@ pread_f(
int Cflag, qflag, uflag, vflag;
int eof = 0, direction = IO_FORWARD;
int c;
+ int preadv2_flags = 0;
Cflag = qflag = uflag = vflag = 0;
init_cvtnum(&fsblocksize, &fssectsize);
@@ -463,15 +475,18 @@ pread_f(
case IO_RANDOM:
if (!zeed) /* srandom seed */
zeed = time(NULL);
- c = read_random(file->fd, offset, count, &total, zeed, eof);
+ c = read_random(file->fd, offset, count, &total, zeed, eof,
+ preadv2_flags);
break;
case IO_FORWARD:
- c = read_forward(file->fd, offset, count, &total, vflag, 0, eof);
+ c = read_forward(file->fd, offset, count, &total, vflag, 0, eof,
+ preadv2_flags);
if (eof)
count = total;
break;
case IO_BACKWARD:
- c = read_backward(file->fd, &offset, &count, &total, eof);
+ c = read_backward(file->fd, &offset, &count, &total, eof,
+ preadv2_flags);
break;
default:
ASSERT(0);
diff --git a/m4/package_libcdev.m4 b/m4/package_libcdev.m4
index 4ef7e8f6..5a1f748a 100644
--- a/m4/package_libcdev.m4
+++ b/m4/package_libcdev.m4
@@ -16,6 +16,24 @@ pwritev2(0, 0, 0, 0, 0);
AC_SUBST(have_pwritev2)
])
+#
+# Check if we have a preadv2 libc call (Linux)
+#
+AC_DEFUN([AC_HAVE_PREADV2],
+ [ AC_MSG_CHECKING([for preadv2])
+ AC_LINK_IFELSE(
+ [ AC_LANG_PROGRAM([[
+#define _GNU_SOURCE
+#include <sys/uio.h>
+ ]], [[
+preadv2(0, 0, 0, 0, 0);
+ ]])
+ ], have_preadv2=yes
+ AC_MSG_RESULT(yes),
+ AC_MSG_RESULT(no))
+ AC_SUBST(have_preadv2)
+ ])
+
#
# Check if we have a copy_file_range system call (Linux)
#
--
2.48.1
