[PATCH 20/31] media: vidtv: simplify PSI write function

From: Mauro Carvalho Chehab
Date: Tue Nov 24 2020 - 06:07:02 EST

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The function vidtv_psi_ts_psi_write_into() initializes the
ts_header fields several times, and receives a struct
as argument, instead of using a pointer to struct.

Cleanup the function, in order to reduce its stack usage
and to avoid initializing the ts_header multiple times.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx>
---
drivers/media/test-drivers/vidtv/vidtv_psi.c | 128 +++++++++----------
1 file changed, 62 insertions(+), 66 deletions(-)

diff --git a/drivers/media/test-drivers/vidtv/vidtv_psi.c b/drivers/media/test-drivers/vidtv/vidtv_psi.c
index 92fdf1149f0d..36f1c56d9e24 100644
--- a/drivers/media/test-drivers/vidtv/vidtv_psi.c
+++ b/drivers/media/test-drivers/vidtv/vidtv_psi.c
@@ -162,79 +162,75 @@ static void vidtv_psi_set_sec_len(struct vidtv_psi_table_header *h, u16 new_len)
* manage the continuity_counter
* add stuffing (i.e. padding bytes) after the CRC
*/
-static u32 vidtv_psi_ts_psi_write_into(struct psi_write_args args)
+static u32 vidtv_psi_ts_psi_write_into(struct psi_write_args *args)
{
-
- u32 nbytes_past_boundary = (args.dest_offset % TS_PACKET_LEN);
+ struct vidtv_mpeg_ts ts_header = {
+ .sync_byte = TS_SYNC_BYTE,
+ .bitfield = cpu_to_be16((args->new_psi_section << 14) | args->pid),
+ .scrambling = 0,
+ .payload = 1,
+ .adaptation_field = 0, /* no adaptation field */
+ };
+ u32 nbytes_past_boundary = (args->dest_offset % TS_PACKET_LEN);
bool aligned = (nbytes_past_boundary == 0);
- struct vidtv_mpeg_ts ts_header = {};
- u32 remaining_len = args.len;
+ u32 remaining_len = args->len;
u32 payload_write_len = 0;
u32 payload_offset = 0;
u32 nbytes = 0;

- const u16 PAYLOAD_START = args.new_psi_section;
-
- if (!args.crc && !args.is_crc)
+ if (!args->crc && !args->is_crc)
pr_warn_ratelimited("Missing CRC for chunk\n");

- if (args.crc)
- *args.crc = dvb_crc32(*args.crc, args.from, args.len);
+ if (args->crc)
+ *args->crc = dvb_crc32(*args->crc, args->from, args->len);

- if (args.new_psi_section && !aligned) {
+ if (args->new_psi_section && !aligned) {
pr_warn_ratelimited("Cannot write a new PSI section in a misaligned buffer\n");

/* forcibly align and hope for the best */
- nbytes += vidtv_memset(args.dest_buf,
- args.dest_offset + nbytes,
- args.dest_buf_sz,
+ nbytes += vidtv_memset(args->dest_buf,
+ args->dest_offset + nbytes,
+ args->dest_buf_sz,
TS_FILL_BYTE,
TS_PACKET_LEN - nbytes_past_boundary);
}

while (remaining_len) {
- nbytes_past_boundary = (args.dest_offset + nbytes) % TS_PACKET_LEN;
+ nbytes_past_boundary = (args->dest_offset + nbytes) % TS_PACKET_LEN;
aligned = (nbytes_past_boundary == 0);

if (aligned) {
/* if at a packet boundary, write a new TS header */
- ts_header.sync_byte = TS_SYNC_BYTE;
- ts_header.bitfield = cpu_to_be16((PAYLOAD_START << 14) | args.pid);
- ts_header.scrambling = 0;
- ts_header.continuity_counter = *args.continuity_counter;
- ts_header.payload = 1;
- /* no adaptation field */
- ts_header.adaptation_field = 0;
+ ts_header.continuity_counter = *args->continuity_counter;

- /* copy the header */
- nbytes += vidtv_memcpy(args.dest_buf,
- args.dest_offset + nbytes,
- args.dest_buf_sz,
+ nbytes += vidtv_memcpy(args->dest_buf,
+ args->dest_offset + nbytes,
+ args->dest_buf_sz,
&ts_header,
sizeof(ts_header));
/*
* This will trigger a discontinuity if the buffer is full,
* effectively dropping the packet.
*/
- vidtv_ts_inc_cc(args.continuity_counter);
+ vidtv_ts_inc_cc(args->continuity_counter);
}

/* write the pointer_field in the first byte of the payload */
- if (args.new_psi_section)
- nbytes += vidtv_memset(args.dest_buf,
- args.dest_offset + nbytes,
- args.dest_buf_sz,
+ if (args->new_psi_section)
+ nbytes += vidtv_memset(args->dest_buf,
+ args->dest_offset + nbytes,
+ args->dest_buf_sz,
0x0,
1);

/* write as much of the payload as possible */
- nbytes_past_boundary = (args.dest_offset + nbytes) % TS_PACKET_LEN;
+ nbytes_past_boundary = (args->dest_offset + nbytes) % TS_PACKET_LEN;
payload_write_len = min(TS_PACKET_LEN - nbytes_past_boundary, remaining_len);

- nbytes += vidtv_memcpy(args.dest_buf,
- args.dest_offset + nbytes,
- args.dest_buf_sz,
- args.from + payload_offset,
+ nbytes += vidtv_memcpy(args->dest_buf,
+ args->dest_offset + nbytes,
+ args->dest_buf_sz,
+ args->from + payload_offset,
payload_write_len);

/* 'payload_write_len' written from a total of 'len' requested*/
@@ -246,12 +242,12 @@ static u32 vidtv_psi_ts_psi_write_into(struct psi_write_args args)
* fill the rest of the packet if there is any remaining space unused
*/

- nbytes_past_boundary = (args.dest_offset + nbytes) % TS_PACKET_LEN;
+ nbytes_past_boundary = (args->dest_offset + nbytes) % TS_PACKET_LEN;

- if (args.is_crc)
- nbytes += vidtv_memset(args.dest_buf,
- args.dest_offset + nbytes,
- args.dest_buf_sz,
+ if (args->is_crc)
+ nbytes += vidtv_memset(args->dest_buf,
+ args->dest_offset + nbytes,
+ args->dest_buf_sz,
TS_FILL_BYTE,
TS_PACKET_LEN - nbytes_past_boundary);

@@ -275,7 +271,7 @@ static u32 table_section_crc32_write_into(struct crc32_write_args args)
psi_args.is_crc = true;
psi_args.dest_buf_sz = args.dest_buf_sz;

- nbytes += vidtv_psi_ts_psi_write_into(psi_args);
+ nbytes += vidtv_psi_ts_psi_write_into(&psi_args);

return nbytes;
}
@@ -662,7 +658,7 @@ static u32 vidtv_psi_desc_write_into(struct desc_write_args args)
psi_args.dest_buf_sz = args.dest_buf_sz;
psi_args.crc = args.crc;

- nbytes += vidtv_psi_ts_psi_write_into(psi_args);
+ nbytes += vidtv_psi_ts_psi_write_into(&psi_args);

switch (args.desc->type) {
case SERVICE_DESCRIPTOR:
@@ -671,25 +667,25 @@ static u32 vidtv_psi_desc_write_into(struct desc_write_args args)
sizeof_field(struct vidtv_psi_desc_service, provider_name_len);
psi_args.from = &((struct vidtv_psi_desc_service *)args.desc)->service_type;

- nbytes += vidtv_psi_ts_psi_write_into(psi_args);
+ nbytes += vidtv_psi_ts_psi_write_into(&psi_args);

psi_args.dest_offset = args.dest_offset + nbytes;
psi_args.len = ((struct vidtv_psi_desc_service *)args.desc)->provider_name_len;
psi_args.from = ((struct vidtv_psi_desc_service *)args.desc)->provider_name;

- nbytes += vidtv_psi_ts_psi_write_into(psi_args);
+ nbytes += vidtv_psi_ts_psi_write_into(&psi_args);

psi_args.dest_offset = args.dest_offset + nbytes;
psi_args.len = sizeof_field(struct vidtv_psi_desc_service, service_name_len);
psi_args.from = &((struct vidtv_psi_desc_service *)args.desc)->service_name_len;

- nbytes += vidtv_psi_ts_psi_write_into(psi_args);
+ nbytes += vidtv_psi_ts_psi_write_into(&psi_args);

psi_args.dest_offset = args.dest_offset + nbytes;
psi_args.len = ((struct vidtv_psi_desc_service *)args.desc)->service_name_len;
psi_args.from = ((struct vidtv_psi_desc_service *)args.desc)->service_name;

- nbytes += vidtv_psi_ts_psi_write_into(psi_args);
+ nbytes += vidtv_psi_ts_psi_write_into(&psi_args);
break;

case NETWORK_NAME_DESCRIPTOR:
@@ -697,7 +693,7 @@ static u32 vidtv_psi_desc_write_into(struct desc_write_args args)
psi_args.len = args.desc->length;
psi_args.from = ((struct vidtv_psi_desc_network_name *)args.desc)->network_name;

- nbytes += vidtv_psi_ts_psi_write_into(psi_args);
+ nbytes += vidtv_psi_ts_psi_write_into(&psi_args);
break;

case SERVICE_LIST_DESCRIPTOR:
@@ -708,7 +704,7 @@ static u32 vidtv_psi_desc_write_into(struct desc_write_args args)
sizeof(struct vidtv_psi_desc_service_list_entry *);
psi_args.from = serv_list_entry;

- nbytes += vidtv_psi_ts_psi_write_into(psi_args);
+ nbytes += vidtv_psi_ts_psi_write_into(&psi_args);

serv_list_entry = serv_list_entry->next;
}
@@ -720,32 +716,32 @@ static u32 vidtv_psi_desc_write_into(struct desc_write_args args)
psi_args.from = ((struct vidtv_psi_desc_short_event *)
args.desc)->iso_language_code;

- nbytes += vidtv_psi_ts_psi_write_into(psi_args);
+ nbytes += vidtv_psi_ts_psi_write_into(&psi_args);

psi_args.dest_offset = args.dest_offset + nbytes;
psi_args.len = sizeof_field(struct vidtv_psi_desc_short_event, event_name_len);
psi_args.from = &((struct vidtv_psi_desc_short_event *)
args.desc)->event_name_len;

- nbytes += vidtv_psi_ts_psi_write_into(psi_args);
+ nbytes += vidtv_psi_ts_psi_write_into(&psi_args);

psi_args.dest_offset = args.dest_offset + nbytes;
psi_args.len = ((struct vidtv_psi_desc_short_event *)args.desc)->event_name_len;
psi_args.from = ((struct vidtv_psi_desc_short_event *)args.desc)->event_name;

- nbytes += vidtv_psi_ts_psi_write_into(psi_args);
+ nbytes += vidtv_psi_ts_psi_write_into(&psi_args);

psi_args.dest_offset = args.dest_offset + nbytes;
psi_args.len = sizeof_field(struct vidtv_psi_desc_short_event, text_len);
psi_args.from = &((struct vidtv_psi_desc_short_event *)args.desc)->text_len;

- nbytes += vidtv_psi_ts_psi_write_into(psi_args);
+ nbytes += vidtv_psi_ts_psi_write_into(&psi_args);

psi_args.dest_offset = args.dest_offset + nbytes;
psi_args.len = ((struct vidtv_psi_desc_short_event *)args.desc)->text_len;
psi_args.from = ((struct vidtv_psi_desc_short_event *)args.desc)->text;

- nbytes += vidtv_psi_ts_psi_write_into(psi_args);
+ nbytes += vidtv_psi_ts_psi_write_into(&psi_args);

break;

@@ -755,7 +751,7 @@ static u32 vidtv_psi_desc_write_into(struct desc_write_args args)
psi_args.len = args.desc->length;
psi_args.from = &args.desc->data;

- nbytes += vidtv_psi_ts_psi_write_into(psi_args);
+ nbytes += vidtv_psi_ts_psi_write_into(&psi_args);
break;
}

@@ -780,7 +776,7 @@ vidtv_psi_table_header_write_into(struct header_write_args args)
psi_args.dest_buf_sz = args.dest_buf_sz;
psi_args.crc = args.crc;

- nbytes += vidtv_psi_ts_psi_write_into(psi_args);
+ nbytes += vidtv_psi_ts_psi_write_into(&psi_args);

return nbytes;
}
@@ -1014,7 +1010,7 @@ u32 vidtv_psi_pat_write_into(struct vidtv_psi_pat_write_args args)
sizeof(struct vidtv_psi_table_pat_program *);
psi_args.dest_offset = args.offset + nbytes;

- nbytes += vidtv_psi_ts_psi_write_into(psi_args);
+ nbytes += vidtv_psi_ts_psi_write_into(&psi_args);

p = p->next;
}
@@ -1207,7 +1203,7 @@ u32 vidtv_psi_pmt_write_into(struct vidtv_psi_pmt_write_args args)
psi_args.dest_buf_sz = args.buf_sz;
psi_args.crc = &crc;

- nbytes += vidtv_psi_ts_psi_write_into(psi_args);
+ nbytes += vidtv_psi_ts_psi_write_into(&psi_args);

while (table_descriptor) {
/* write the descriptors, if any */
@@ -1232,7 +1228,7 @@ u32 vidtv_psi_pmt_write_into(struct vidtv_psi_pmt_write_args args)
sizeof_field(struct vidtv_psi_table_pmt_stream, bitfield2);
psi_args.dest_offset = args.offset + nbytes;

- nbytes += vidtv_psi_ts_psi_write_into(psi_args);
+ nbytes += vidtv_psi_ts_psi_write_into(&psi_args);

stream_descriptor = stream->descriptor;

@@ -1360,7 +1356,7 @@ u32 vidtv_psi_sdt_write_into(struct vidtv_psi_sdt_write_args args)
psi_args.crc = &crc;

/* copy u16 network_id + u8 reserved)*/
- nbytes += vidtv_psi_ts_psi_write_into(psi_args);
+ nbytes += vidtv_psi_ts_psi_write_into(&psi_args);

while (service) {
/* copy the services, if any */
@@ -1371,7 +1367,7 @@ u32 vidtv_psi_sdt_write_into(struct vidtv_psi_sdt_write_args args)
sizeof(struct vidtv_psi_table_sdt_service *);
psi_args.dest_offset = args.offset + nbytes;

- nbytes += vidtv_psi_ts_psi_write_into(psi_args);
+ nbytes += vidtv_psi_ts_psi_write_into(&psi_args);

service_desc = service->descriptor;

@@ -1694,7 +1690,7 @@ u32 vidtv_psi_nit_write_into(struct vidtv_psi_nit_write_args args)
psi_args.dest_buf_sz = args.buf_sz;
psi_args.crc = &crc;

- nbytes += vidtv_psi_ts_psi_write_into(psi_args);
+ nbytes += vidtv_psi_ts_psi_write_into(&psi_args);

while (table_descriptor) {
/* write the descriptors, if any */
@@ -1718,7 +1714,7 @@ u32 vidtv_psi_nit_write_into(struct vidtv_psi_nit_write_args args)
psi_args.dest_offset = args.offset + nbytes;
psi_args.pid = VIDTV_NIT_PID;

- nbytes += vidtv_psi_ts_psi_write_into(psi_args);
+ nbytes += vidtv_psi_ts_psi_write_into(&psi_args);

while (transport) {
/* write the transport sections, if any */
@@ -1728,7 +1724,7 @@ u32 vidtv_psi_nit_write_into(struct vidtv_psi_nit_write_args args)
sizeof_field(struct vidtv_psi_table_transport, bitfield);
psi_args.dest_offset = args.offset + nbytes;

- nbytes += vidtv_psi_ts_psi_write_into(psi_args);
+ nbytes += vidtv_psi_ts_psi_write_into(&psi_args);

transport_descriptor = transport->descriptor;

@@ -1907,7 +1903,7 @@ u32 vidtv_psi_eit_write_into(struct vidtv_psi_eit_write_args args)
psi_args.dest_buf_sz = args.buf_sz;
psi_args.crc = &crc;

- nbytes += vidtv_psi_ts_psi_write_into(psi_args);
+ nbytes += vidtv_psi_ts_psi_write_into(&psi_args);

while (event) {
/* copy the events, if any */
@@ -1918,7 +1914,7 @@ u32 vidtv_psi_eit_write_into(struct vidtv_psi_eit_write_args args)
sizeof(struct vidtv_psi_table_eit_event *);
psi_args.dest_offset = args.offset + nbytes;

- nbytes += vidtv_psi_ts_psi_write_into(psi_args);
+ nbytes += vidtv_psi_ts_psi_write_into(&psi_args);

event_descriptor = event->descriptor;

--
2.28.0

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