lttng lib: ring buffer move null pointer check to open

[lttng-modules.git] / lib / ringbuffer / ring_buffer_vfs.c

diff --git a/lib/ringbuffer/ring_buffer_vfs.c b/lib/ringbuffer/ring_buffer_vfs.c
index 2558ab667666be50b29eb9df484d4ea3773d140d..8b783052a5f6cbe510e218120f6c16b56ebc96c5 100644 (file)
--- a/lib/ringbuffer/ring_buffer_vfs.c
+++ b/lib/ringbuffer/ring_buffer_vfs.c
@@ -42,6 +42,9 @@ int lib_ring_buffer_open(struct inode *inode, struct file *file)
        struct lib_ring_buffer *buf = inode->i_private;
        int ret;
 
+       if (!buf)
+               return -EINVAL;
+
        ret = lib_ring_buffer_open_read(buf);
        if (ret)
                return ret;
@@ -86,19 +89,24 @@ unsigned int lib_ring_buffer_poll(struct file *filp, poll_table *wait)
        struct lib_ring_buffer *buf = filp->private_data;
        struct channel *chan = buf->backend.chan;
        const struct lib_ring_buffer_config *config = chan->backend.config;
-       int finalized;
+       int finalized, disabled;
 
        if (filp->f_mode & FMODE_READ) {
-               init_poll_funcptr(wait, wrapper_pollwait_exclusive);
+               poll_wait_set_exclusive(wait);
                poll_wait(filp, &buf->read_wait, wait);
 
                finalized = lib_ring_buffer_is_finalized(config, buf);
+               disabled = lib_ring_buffer_channel_is_disabled(chan);
+
                /*
                 * lib_ring_buffer_is_finalized() contains a smp_rmb() ordering
                 * finalized load before offsets loads.
                 */
                WARN_ON(atomic_long_read(&buf->active_readers) != 1);
 retry:
+               if (disabled)
+                       return POLLERR;
+
                if (subbuf_trunc(lib_ring_buffer_get_offset(config, buf), chan)
                  - subbuf_trunc(lib_ring_buffer_get_consumed(config, buf), chan)
                  == 0) {
@@ -159,6 +167,9 @@ long lib_ring_buffer_ioctl(struct file *filp, unsigned int cmd, unsigned long ar
        struct channel *chan = buf->backend.chan;
        const struct lib_ring_buffer_config *config = chan->backend.config;
 
+       if (lib_ring_buffer_channel_is_disabled(chan))
+               return -EIO;
+
        switch (cmd) {
        case RING_BUFFER_SNAPSHOT:
                return lib_ring_buffer_snapshot(buf, &buf->cons_snapshot,
@@ -237,6 +248,9 @@ long lib_ring_buffer_ioctl(struct file *filp, unsigned int cmd, unsigned long ar
                return put_ulong(buf->backend.array[sb_bindex]->mmap_offset,
                                 arg);
        }
+       case RING_BUFFER_FLUSH:
+               lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
+               return 0;
        default:
                return -ENOIOCTLCMD;
        }
@@ -250,6 +264,9 @@ long lib_ring_buffer_compat_ioctl(struct file *filp, unsigned int cmd,
        struct channel *chan = buf->backend.chan;
        const struct lib_ring_buffer_config *config = chan->backend.config;
 
+       if (lib_ring_buffer_channel_is_disabled(chan))
+               return -EIO;
+
        switch (cmd) {
        case RING_BUFFER_SNAPSHOT:
                return lib_ring_buffer_snapshot(buf, &buf->cons_snapshot,
@@ -344,6 +361,9 @@ long lib_ring_buffer_compat_ioctl(struct file *filp, unsigned int cmd,
                        return -EINVAL;
                return put_ulong(read_offset, arg);
        }
+       case RING_BUFFER_FLUSH:
+               lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
+               return 0;
        default:
                return -ENOIOCTLCMD;
        }
@@ -351,6 +371,7 @@ long lib_ring_buffer_compat_ioctl(struct file *filp, unsigned int cmd,
 #endif
 
 const struct file_operations lib_ring_buffer_file_operations = {
+       .owner = THIS_MODULE,
        .open = lib_ring_buffer_open,
        .release = lib_ring_buffer_release,
        .poll = lib_ring_buffer_poll,