| Message ID | 2f79194719d79c71b905be26c4537292649312b2.camel@kernel.crashing.org |
|---|---|
| State | Accepted |
| Headers | show |
| Series | [1/2] i2c: Fix multiple-enqueue of the same request on NACK | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | master/apply_patch Successfully applied |
| snowpatch_ozlabs/make_check | success | Test make_check on branch master |
diff --git a/core/i2c.c b/core/i2c.c index 070a0f6f..e8333105 100644 --- a/core/i2c.c +++ b/core/i2c.c @@ -20,6 +20,7 @@ #include <device.h> #include <opal-msg.h> #include <timebase.h> +#include <processor.h> static LIST_HEAD(i2c_bus_list); @@ -148,6 +149,7 @@ static void i2c_sync_request_complete(int rc, struct i2c_request *req) { struct i2c_sync_userdata *ud = req->user_data; ud->rc = rc; + lwsync(); ud->done = true; } @@ -222,6 +224,7 @@ int i2c_request_send(int bus_id, int dev_addr, int read_write, waited += time_to_wait; } while (!ud.done); + lwsync(); rc = ud.rc; /* error or success */
i2c_request_send loops waiting for a flag "uc.done" set by the completion routine, and then look for a result code also set by that same completion. There is no synchronization, the completion can happen on another processor, so we need to order the stores to uc and the reads from uc so that uc.done is stored last and tested first using memory barriers. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> --- core/i2c.c | 3 +++ 1 file changed, 3 insertions(+)