lib/loopdev: consolidate ioctls calls on EAGAIN

Keep all logic to repeat ioctl calls in one macro rather than
duplicate code.

Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/lib/loopdev.c b/lib/loopdev.c
index 3cf72ebb9472c4477544ada76a5cc5cc7b5f9756..437411bbea7d1a0f5db6eed01438c1ad2f3b24e7 100644 (file)
--- a/lib/loopdev.c
+++ b/lib/loopdev.c
@@ -43,7 +43,6 @@
 #include "debug.h"
 #include "fileutils.h"
 
-
 #define LOOPDEV_MAX_TRIES      10
 
 /*
@@ -77,6 +76,24 @@ static void loopdev_init_debug(void)
 #define loopcxt_sysfs_available(_lc)   (!((_lc)->flags & LOOPDEV_FL_NOSYSFS)) \
                                         && !loopcxt_ioctl_enabled(_lc)
 
+/*
+ * Calls @x and repeat on EAGAIN
+ */
+#define repeat_on_eagain(x) __extension__ ({                   \
+               int _c = 0, _e;                                 \
+               do {                                            \
+                       errno = 0;                              \
+                       _e = x;                                 \
+                       if (_e == 0 || errno != EAGAIN)         \
+                               break;                          \
+                       if (_c >= LOOPDEV_MAX_TRIES)            \
+                               break;                          \
+                       xusleep(250000);                        \
+                       _c++;                                   \
+               } while (1);                                    \
+               _e == 0 ? 0 : errno ? -errno : -1;              \
+       })
+
 /*
  * @lc: context
  * @device: device name, absolute device path or NULL to reset the current setting
@@ -1276,6 +1293,7 @@ static int loopcxt_check_size(struct loopdev_cxt *lc, int file_fd)
        return 0;
 }
 
+
 /*
  * @lc: context
  *
@@ -1367,8 +1385,9 @@ int loopcxt_setup_device(struct loopdev_cxt *lc)
         * -- since Linux v5.8-rc1, commit 3448914e8cc550ba792d4ccc74471d1ca4293aae
         */
        lc->config.fd = file_fd;
-       if (ioctl(dev_fd, LOOP_CONFIGURE, &lc->config) < 0) {
-               rc = -errno;
+
+       rc = repeat_on_eagain( ioctl(dev_fd, LOOP_CONFIGURE, &lc->config) );
+       if (rc != 0) {
                errsv = errno;
                if (errno != EINVAL && errno != ENOTTY && errno != ENOSYS) {
                        DBG(SETUP, ul_debugobj(lc, "LOOP_CONFIGURE failed: %m"));
@@ -1433,6 +1452,7 @@ err:
        return rc;
 }
 
+
 /*
  * @lc: context
  *
@@ -1446,28 +1466,18 @@ err:
  */
 int loopcxt_ioctl_status(struct loopdev_cxt *lc)
 {
-       int dev_fd, rc = -1, err, again, tries = 0;
+       int dev_fd, rc;
 
        errno = 0;
        dev_fd = loopcxt_get_fd(lc);
 
-       if (dev_fd < 0) {
-               rc = -errno;
-               return rc;
-       }
-       DBG(SETUP, ul_debugobj(lc, "device open: OK"));
+       if (dev_fd < 0)
+               return -errno;
 
-       do {
-               err = ioctl(dev_fd, LOOP_SET_STATUS64, &lc->config.info);
-               again = err && errno == EAGAIN;
-               if (again) {
-                       xusleep(250000);
-                       tries++;
-               }
-       } while (again && tries <= LOOPDEV_MAX_TRIES);
+       DBG(SETUP, ul_debugobj(lc, "calling LOOP_SET_STATUS64"));
 
-       if (err) {
-               rc = -errno;
+       rc = repeat_on_eagain( ioctl(dev_fd, LOOP_SET_STATUS64, &lc->config.info) );
+       if (rc != 0) {
                DBG(SETUP, ul_debugobj(lc, "LOOP_SET_STATUS64 failed: %m"));
                return rc;
        }
@@ -1478,14 +1488,16 @@ int loopcxt_ioctl_status(struct loopdev_cxt *lc)
 
 int loopcxt_ioctl_capacity(struct loopdev_cxt *lc)
 {
-       int fd = loopcxt_get_fd(lc);
+       int rc, fd = loopcxt_get_fd(lc);
 
        if (fd < 0)
                return -EINVAL;
 
+       DBG(SETUP, ul_debugobj(lc, "calling LOOP_SET_CAPACITY"));
+
        /* Kernels prior to v2.6.30 don't support this ioctl */
-       if (ioctl(fd, LOOP_SET_CAPACITY, 0) < 0) {
-               int rc = -errno;
+       rc = repeat_on_eagain( ioctl(fd, LOOP_SET_CAPACITY, 0) );
+       if (rc != 0) {
                DBG(CXT, ul_debugobj(lc, "LOOP_SET_CAPACITY failed: %m"));
                return rc;
        }
@@ -1496,14 +1508,16 @@ int loopcxt_ioctl_capacity(struct loopdev_cxt *lc)
 
 int loopcxt_ioctl_dio(struct loopdev_cxt *lc, unsigned long use_dio)
 {
-       int fd = loopcxt_get_fd(lc);
+       int rc, fd = loopcxt_get_fd(lc);
 
        if (fd < 0)
                return -EINVAL;
 
+       DBG(SETUP, ul_debugobj(lc, "calling LOOP_SET_DIRECT_IO"));
+
        /* Kernels prior to v4.4 don't support this ioctl */
-       if (ioctl(fd, LOOP_SET_DIRECT_IO, use_dio) < 0) {
-               int rc = -errno;
+       rc = repeat_on_eagain( ioctl(fd, LOOP_SET_DIRECT_IO, use_dio) );
+       if (rc != 0) {
                DBG(CXT, ul_debugobj(lc, "LOOP_SET_DIRECT_IO failed: %m"));
                return rc;
        }
@@ -1518,25 +1532,19 @@ int loopcxt_ioctl_dio(struct loopdev_cxt *lc, unsigned long use_dio)
  */
 int loopcxt_ioctl_blocksize(struct loopdev_cxt *lc, uint64_t blocksize)
 {
-       int fd = loopcxt_get_fd(lc);
-       int err, again, tries = 0;
+       int rc, fd = loopcxt_get_fd(lc);
 
        if (fd < 0)
                return -EINVAL;
 
-       do {
-               /* Kernels prior to v4.14 don't support this ioctl */
-               err = ioctl(fd, LOOP_SET_BLOCK_SIZE, (unsigned long) blocksize);
-               again = err && errno == EAGAIN;
-               if (again) {
-                       xusleep(250000);
-                       tries++;
-               } else if (err) {
-                       int rc = -errno;
-                       DBG(CXT, ul_debugobj(lc, "LOOP_SET_BLOCK_SIZE failed: %m"));
-                       return rc;
-               }
-       } while (again && tries <= LOOPDEV_MAX_TRIES);
+       DBG(SETUP, ul_debugobj(lc, "calling LOOP_SET_BLOCK_SIZE"));
+
+       rc = repeat_on_eagain(
+               ioctl(fd, LOOP_SET_BLOCK_SIZE, (unsigned long) blocksize) );
+       if (rc != 0) {
+               DBG(CXT, ul_debugobj(lc, "LOOP_SET_BLOCK_SIZE failed: %m"));
+               return rc;
+       }
 
        DBG(CXT, ul_debugobj(lc, "logical block size set"));
        return 0;
@@ -1544,14 +1552,17 @@ int loopcxt_ioctl_blocksize(struct loopdev_cxt *lc, uint64_t blocksize)
 
 int loopcxt_delete_device(struct loopdev_cxt *lc)
 {
-       int fd = loopcxt_get_fd(lc);
+       int rc, fd = loopcxt_get_fd(lc);
 
        if (fd < 0)
                return -EINVAL;
 
-       if (ioctl(fd, LOOP_CLR_FD, 0) < 0) {
+       DBG(SETUP, ul_debugobj(lc, "calling LOOP_SET_CLR_FD"));
+
+       rc = repeat_on_eagain( ioctl(fd, LOOP_CLR_FD, 0) );
+       if (rc != 0) {
                DBG(CXT, ul_debugobj(lc, "LOOP_CLR_FD failed: %m"));
-               return -errno;
+               return rc;
        }
 
        DBG(CXT, ul_debugobj(lc, "device removed"));