[PATCH 1/5] mei: allow map and unmap of client dma buffer only for disconnected client
From: Emmanuel Grumbach <hidden>
Date: 2021-03-22 20:43:07
Subsystem:
char and misc drivers, intel management engine (mei), the rest · Maintainers:
Arnd Bergmann, Greg Kroah-Hartman, Alexander Usyskin, Linus Torvalds
From: Tomas Winkler <redacted> Allow map and unmap of the client dma buffer only when the client is not connected. The functions return -EPROTO if the client is already connected. This is to fix the race when traffic may start or stop when buffer is not available. Signed-off-by: Tomas Winkler <redacted> Signed-off-by: Emmanuel Grumbach <redacted> --- drivers/misc/mei/client.c | 17 +++++++---------- 1 file changed, 7 insertions(+), 10 deletions(-)
diff --git a/drivers/misc/mei/client.c b/drivers/misc/mei/client.c
index 4378a9b25848..2cc370adb238 100644
--- a/drivers/misc/mei/client.c
+++ b/drivers/misc/mei/client.c@@ -2286,8 +2286,8 @@ int mei_cl_dma_alloc_and_map(struct mei_cl *cl, const struct file *fp, if (buffer_id == 0) return -EINVAL; - if (!mei_cl_is_connected(cl)) - return -ENODEV; + if (mei_cl_is_connected(cl)) + return -EPROTO; if (cl->dma_mapped) return -EPROTO;
@@ -2327,9 +2327,7 @@ int mei_cl_dma_alloc_and_map(struct mei_cl *cl, const struct file *fp, mutex_unlock(&dev->device_lock); wait_event_timeout(cl->wait, - cl->dma_mapped || - cl->status || - !mei_cl_is_connected(cl), + cl->dma_mapped || cl->status, mei_secs_to_jiffies(MEI_CL_CONNECT_TIMEOUT)); mutex_lock(&dev->device_lock);
@@ -2376,8 +2374,9 @@ int mei_cl_dma_unmap(struct mei_cl *cl, const struct file *fp) return -EOPNOTSUPP; } - if (!mei_cl_is_connected(cl)) - return -ENODEV; + /* do not allow unmap for connected client */ + if (mei_cl_is_connected(cl)) + return -EPROTO; if (!cl->dma_mapped) return -EPROTO;
@@ -2405,9 +2404,7 @@ int mei_cl_dma_unmap(struct mei_cl *cl, const struct file *fp) mutex_unlock(&dev->device_lock); wait_event_timeout(cl->wait, - !cl->dma_mapped || - cl->status || - !mei_cl_is_connected(cl), + !cl->dma_mapped || cl->status, mei_secs_to_jiffies(MEI_CL_CONNECT_TIMEOUT)); mutex_lock(&dev->device_lock);
--
2.25.1