Step 6 of micro-refactoring the set_loop():
Use structs to avoid transferring a large number of parameters
in set_loop_configure() and set_loop_info()
function old new delta
set_loop 708 720 +12
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/0 up/down: 12/0) Total: 12 bytes
Signed-off-by: Xiaoming Ni <nixiaom...@huawei.com>
---
libbb/loop.c | 54 +++++++++++++++++++++++++++++-----------------------
1 file changed, 30 insertions(+), 24 deletions(-)
diff --git a/libbb/loop.c b/libbb/loop.c
index 914af57b2..2200ccb9a 100644
--- a/libbb/loop.c
+++ b/libbb/loop.c
@@ -126,32 +126,21 @@ static int open_file(const char *file, unsigned flags,
int *mode)
return ffd;
}
-static int set_loop_configure(int ffd, int lfd, const char *file,
- unsigned long long offset, unsigned long long sizelimit,
unsigned flags)
+static int set_loop_configure(int ffd, int lfd, bb_loop_info *loopinfo)
{
int rc;
- bb_loop_info loopinfo;
+ bb_loop_info loopinfo2;
/* Associate free loop device with file */
if (ioctl(lfd, LOOP_SET_FD, ffd)) {
return -1;
}
- memset(&loopinfo, 0, sizeof(loopinfo));
- safe_strncpy((char *)loopinfo.lo_file_name, file, LO_NAME_SIZE);
- loopinfo.lo_offset = offset;
- loopinfo.lo_sizelimit = sizelimit;
- /*
- * Used by mount to set LO_FLAGS_AUTOCLEAR.
- * LO_FLAGS_READ_ONLY is not set because RO is controlled by open type
of the file.
- * Note that closing LO_FLAGS_AUTOCLEARed lfd before mount
- * is wrong (would free the loop device!)
- */
- loopinfo.lo_flags = (flags & ~BB_LO_FLAGS_READ_ONLY);
- rc = ioctl(lfd, BB_LOOP_SET_STATUS, &loopinfo);
- if (rc != 0 && (loopinfo.lo_flags & BB_LO_FLAGS_AUTOCLEAR)) {
+ rc = ioctl(lfd, BB_LOOP_SET_STATUS, loopinfo);
+ if (rc != 0 && (loopinfo->lo_flags & BB_LO_FLAGS_AUTOCLEAR)) {
+ memcpy(&loopinfo2, loopinfo, sizeof(*loopinfo));
/* Old kernel, does not support LO_FLAGS_AUTOCLEAR? */
/* (this code path is not tested) */
- loopinfo.lo_flags -= BB_LO_FLAGS_AUTOCLEAR;
- rc = ioctl(lfd, BB_LOOP_SET_STATUS, &loopinfo);
+ loopinfo2.lo_flags -= BB_LO_FLAGS_AUTOCLEAR;
+ rc = ioctl(lfd, BB_LOOP_SET_STATUS, &loopinfo2);
}
if (rc == 0) {
return lfd;
@@ -161,21 +150,36 @@ static int set_loop_configure(int ffd, int lfd, const
char *file,
return -1;
}
-static int set_loop_info(int ffd, int lfd, const char *file,
- unsigned long long offset, unsigned long long sizelimit,
unsigned flags)
+static int set_loop_info(int ffd, int lfd, bb_loop_info *loopinfo)
{
int rc;
- bb_loop_info loopinfo;
+ bb_loop_info tmp;
- rc = ioctl(lfd, BB_LOOP_GET_STATUS, &loopinfo);
+ rc = ioctl(lfd, BB_LOOP_GET_STATUS, &tmp);
/* If device is free, try to claim it */
if (rc && errno == ENXIO) {
- return set_loop_configure(ffd, lfd, file, offset, sizelimit,
flags);
+ return set_loop_configure(ffd, lfd, loopinfo);
}
return -1;
}
+static void init_bb_loop_info(bb_loop_info *loopinfo, const char *file,
+ unsigned long long offset, unsigned long long sizelimit,
unsigned flags)
+{
+ memset(loopinfo, 0, sizeof(*loopinfo));
+ safe_strncpy((char *)loopinfo->lo_file_name, file, LO_NAME_SIZE);
+ loopinfo->lo_offset = offset;
+ loopinfo->lo_sizelimit = sizelimit;
+ /*
+ * Used by mount to set LO_FLAGS_AUTOCLEAR.
+ * LO_FLAGS_READ_ONLY is not set because RO is controlled by open type
of the file.
+ * Note that closing LO_FLAGS_AUTOCLEARed lfd before mount
+ * is wrong (would free the loop device!)
+ */
+ loopinfo->lo_flags = (flags & ~BB_LO_FLAGS_READ_ONLY);
+}
+
/* Returns opened fd to the loop device, <0 on error.
* *device is loop device to use, or if *device==NULL finds a loop device to
* mount it on and sets *device to a strdup of that loop device name.
@@ -187,12 +191,14 @@ int FAST_FUNC set_loop(char **device, const char *file,
unsigned long long offse
char *try;
struct stat statbuf;
int i, lfd, ffd, mode, rc;
+ bb_loop_info loopinfo;
ffd = open_file(file, flags, &mode);
if (ffd < 0) {
return -errno;
}
+ init_bb_loop_info(&loopinfo, file, offset, sizelimit, flags);
try = *device;
if (!try) {
try = dev;
@@ -239,7 +245,7 @@ int FAST_FUNC set_loop(char **device, const char *file,
unsigned long long offse
}
goto try_next_loopN;
}
- rc = set_loop_info(ffd, lfd, file, offset, sizelimit, flags);
+ rc = set_loop_info(ffd, lfd, &loopinfo);
if (rc == lfd) {
/* SUCCESS! */
if (!*device)
--
2.27.0
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