From: Duncan Laurie dlaurie@chromium.org
[ Upstream commit 655603de68469adaff16842ac17a5aec9c9ce89b ]
The sysfs handler should return the number of bytes consumed, which in the case of a successful write is the entire buffer. Also fix a bug where param.data_len was being set to (count - (2 * sizeof(u32))) instead of just (count - sizeof(u32)). The latter is correct because we skip over the leading u32 which is our param.type, but we were also incorrectly subtracting sizeof(u32) on the line where we were actually setting param.data_len:
param.data_len = count - sizeof(u32);
This meant that for our example event.kernel_software_watchdog with total length 10 bytes, param.data_len was just 2 prior to this change.
To test, successfully append an event to the log with gsmi sysfs. This sample event is for a "Kernel Software Watchdog"
xxd -g 1 event.kernel_software_watchdog
0000000: 01 00 00 00 ad de 06 00 00 00
cat event.kernel_software_watchdog > /sys/firmware/gsmi/append_to_eventlog
mosys eventlog list | tail -1
14 | 2012-06-25 10:14:14 | Kernl Event | Software Watchdog
Signed-off-by: Duncan Laurie dlaurie@chromium.org Reviewed-by: Vadim Bendebury vbendeb@chromium.org Reviewed-by: Stefan Reinauer reinauer@chromium.org Signed-off-by: Furquan Shaikh furquan@google.com Tested-by: Furquan Shaikh furquan@chromium.org Reviewed-by: Aaron Durbin adurbin@chromium.org Reviewed-by: Justin TerAvest teravest@chromium.org [zwisler: updated changelog for 2nd bug fix and upstream] Signed-off-by: Ross Zwisler zwisler@google.com Reviewed-by: Guenter Roeck groeck@chromium.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/firmware/google/gsmi.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/firmware/google/gsmi.c b/drivers/firmware/google/gsmi.c index c8f169bf2e27d..62337be07afcb 100644 --- a/drivers/firmware/google/gsmi.c +++ b/drivers/firmware/google/gsmi.c @@ -480,11 +480,10 @@ static ssize_t eventlog_write(struct file *filp, struct kobject *kobj, if (count < sizeof(u32)) return -EINVAL; param.type = *(u32 *)buf; - count -= sizeof(u32); buf += sizeof(u32);
/* The remaining buffer is the data payload */ - if (count > gsmi_dev.data_buf->length) + if ((count - sizeof(u32)) > gsmi_dev.data_buf->length) return -EINVAL; param.data_len = count - sizeof(u32);
@@ -504,7 +503,7 @@ static ssize_t eventlog_write(struct file *filp, struct kobject *kobj,
spin_unlock_irqrestore(&gsmi_dev.lock, flags);
- return rc; + return (rc == 0) ? count : rc;
}