Return POLLERR if channel is disabled (error state)

[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..fecef217c8bfdd9a51587f930a5dc7c2dcecac64 100644 (file)
--- a/lib/ringbuffer/ring_buffer_vfs.c
+++ b/lib/ringbuffer/ring_buffer_vfs.c
@@ -86,19 +86,24 @@ 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(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 +164,9 @@ 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,
@@ -250,6 +258,9 @@ 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,