libbb: if opening /dev/loopN returns ENXIO, don't try N++.

function                                             old     new   delta
set_loop                                             639     635      -4

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 12 insertions, 6 deletions

diff --git a/libbb/loop.c b/libbb/loop.c
index 823fba079..c96c5e070 100644
--- a/libbb/loop.c
+++ b/libbb/loop.c
@@ -94,19 +94,19 @@ int FAST_FUNC set_loop(char **device, const char *file, unsigned long long offse
 
         /* Open the file.  Barf if this doesn't work.  */
         mode = ro ? O_RDONLY : O_RDWR;
+ open_ffd:
         ffd = open(file, mode);
         if (ffd < 0) {
                 if (mode != O_RDONLY) {
                         mode = O_RDONLY;
-                        ffd = open(file, mode);
+                        goto open_ffd;
                 }
-                if (ffd < 0)
-                        return -errno;
+                return -errno;
         }
 
         /* Find a loop device.  */
         try = *device ? *device : dev;
-        /* 1048575 is a max possible minor number in Linux circa 2010 */
+        /* 1048575 (0xfffff) is a max possible minor number in Linux circa 2010 */
         for (i = 0; rc && i < 1048576; i++) {
                 sprintf(dev, LOOP_FORMAT, i);
 
@@ -121,7 +121,7 @@ int FAST_FUNC set_loop(char **device, const char *file, unsigned long long offse
                                         goto try_to_open;
                         }
                         /* Ran out of block devices, return failure.  */
-                        rc = -ENOENT;
+                        rc = -1;
                         break;
                 }
  try_to_open:
@@ -131,8 +131,14 @@ int FAST_FUNC set_loop(char **device, const char *file, unsigned long long offse
                         mode = O_RDONLY;
                         dfd = open(try, mode);
                 }
-                if (dfd < 0)
+                if (dfd < 0) {
+                        if (errno == ENXIO) {
+                                /* Happens if loop module is not loaded */
+                                rc = -1;
+                                break;
+                        }
                         goto try_again;
+                }
 
                 rc = ioctl(dfd, BB_LOOP_GET_STATUS, &loopinfo);