[PATCH] blkparse: be sure to propagate read_data() error all the way back

diff --git a/blkparse.c b/blkparse.c
index 8a90362c25454e865048618f180f3ccb4532a7b2..4a14f3276d6acfd5bc64562b15171bf57b029e12 100644 (file)
--- a/blkparse.c
+++ b/blkparse.c
@@ -1725,8 +1725,10 @@ static int read_data(int fd, void *buffer, int bytes, int block, int *fdblock)
                if (!ret)
                        return 1;
                else if (ret < 0) {
-                       if (errno != EAGAIN)
+                       if (errno != EAGAIN) {
                                perror("read");
+                               return -1;
+                       }
 
                        /*
                         * never do partial reads. we can return if we
@@ -1755,15 +1757,18 @@ static int read_events(int fd, int always_block, int *fdblock)
        while (!is_done() && events < rb_batch) {
                struct blk_io_trace *bit;
                struct trace *t;
-               int pdu_len, should_block;
+               int pdu_len, should_block, ret;
                __u32 magic;
 
                bit = bit_alloc();
 
                should_block = !events || always_block;
 
-               if (read_data(fd, bit, sizeof(*bit), should_block, fdblock)) {
+               ret = read_data(fd, bit, sizeof(*bit), should_block, fdblock);
+               if (ret) {
                        bit_free(bit);
+                       if (!events && ret < 0)
+                               events = ret;
                        break;
                }
 
@@ -1886,7 +1891,7 @@ static int do_file(void)
                                        continue;
 
                                events = read_events(pci->fd, 1, &pci->fdblock);
-                               if (!events) {
+                               if (events <= 0) {
                                        cpu_mark_offline(pdi, pci->cpu);
                                        close(pci->fd);
                                        pci->fd = -1;
@@ -1929,7 +1934,7 @@ static int do_stdin(void)
        }
 
        fdblock = -1;
-       while ((events = read_events(fd, 0, &fdblock)) != 0) {
+       while ((events = read_events(fd, 0, &fdblock)) > 0) {
        
                smallest_seq_read = -1U;