diff options
| -rw-r--r-- | drivers/hwtracing/stm/core.c | 19 | ||||
| -rw-r--r-- | include/linux/stm.h | 7 |
2 files changed, 19 insertions, 7 deletions
diff --git a/drivers/hwtracing/stm/core.c b/drivers/hwtracing/stm/core.c index 79cca94bfb58..0db303b50e51 100644 --- a/drivers/hwtracing/stm/core.c +++ b/drivers/hwtracing/stm/core.c @@ -380,8 +380,8 @@ static int stm_file_assign(struct stm_file *stmf, char *id, unsigned int width) return ret; } -static void stm_write(struct stm_data *data, unsigned int master, - unsigned int channel, const char *buf, size_t count) +static ssize_t stm_write(struct stm_data *data, unsigned int master, + unsigned int channel, const char *buf, size_t count) { unsigned int flags = STP_PACKET_TIMESTAMPED; const unsigned char *p = buf, nil = 0; @@ -393,9 +393,14 @@ static void stm_write(struct stm_data *data, unsigned int master, sz = data->packet(data, master, channel, STP_PACKET_DATA, flags, sz, p); flags = 0; + + if (sz < 0) + break; } data->packet(data, master, channel, STP_PACKET_FLAG, 0, 0, &nil); + + return pos; } static ssize_t stm_char_write(struct file *file, const char __user *buf, @@ -433,8 +438,8 @@ static ssize_t stm_char_write(struct file *file, const char __user *buf, return -EFAULT; } - stm_write(stm->data, stmf->output.master, stmf->output.channel, kbuf, - count); + count = stm_write(stm->data, stmf->output.master, stmf->output.channel, + kbuf, count); kfree(kbuf); @@ -996,9 +1001,9 @@ int stm_source_write(struct stm_source_data *data, unsigned int chan, stm = srcu_dereference(src->link, &stm_source_srcu); if (stm) - stm_write(stm->data, src->output.master, - src->output.channel + chan, - buf, count); + count = stm_write(stm->data, src->output.master, + src->output.channel + chan, + buf, count); else count = -ENODEV; diff --git a/include/linux/stm.h b/include/linux/stm.h index 9d0083d364e6..ab8ceca4f570 100644 --- a/include/linux/stm.h +++ b/include/linux/stm.h @@ -67,6 +67,13 @@ struct stm_device; * description. That is, the lowest master that can be allocated to software * writers is @sw_start and data from this writer will appear is @sw_start * master in the STP stream. + * + * The @packet callback should adhere to the following rules: + * 1) it must return the number of bytes it consumed from the payload; + * 2) therefore, if it sent a packet that does not have payload (like FLAG), + * it must return zero; + * 3) if it does not support the requested packet type/flag combination, + * it must return -ENOTSUPP. */ struct stm_data { const char *name; |