From: Andrew de Quincey Date: Thu, 1 Dec 2005 08:51:49 +0000 (-0800) Subject: [PATCH] DVB: Fix locking problems and code cleanup X-Git-Tag: v2.6.15-rc5~32 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ded928468407c8e08dcb6aedb91aaa97b80d5752;p=linux-2.6 [PATCH] DVB: Fix locking problems and code cleanup Fix locking problems and code cleanup Signed-off-by: Andrew de Quincey Signed-off-by: Johannes Stezenbach Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/drivers/media/dvb/dvb-core/dvb_ca_en50221.c b/drivers/media/dvb/dvb-core/dvb_ca_en50221.c index 2aa767f9bd..cb2e7d6ba2 100644 --- a/drivers/media/dvb/dvb-core/dvb_ca_en50221.c +++ b/drivers/media/dvb/dvb-core/dvb_ca_en50221.c @@ -35,7 +35,7 @@ #include #include #include -#include +#include #include #include "dvb_ca_en50221.h" @@ -111,9 +111,6 @@ struct dvb_ca_slot { /* size of the buffer to use when talking to the CAM */ int link_buf_size; - /* semaphore for syncing access to slot structure */ - struct rw_semaphore sem; - /* buffer for incoming packets */ struct dvb_ringbuffer rx_buffer; @@ -602,14 +599,11 @@ static int dvb_ca_en50221_read_data(struct dvb_ca_private *ca, int slot, u8 * eb if (ebuf == NULL) { int buf_free; - down_read(&ca->slot_info[slot].sem); if (ca->slot_info[slot].rx_buffer.data == NULL) { - up_read(&ca->slot_info[slot].sem); status = -EIO; goto exit; } buf_free = dvb_ringbuffer_free(&ca->slot_info[slot].rx_buffer); - up_read(&ca->slot_info[slot].sem); if (buf_free < (ca->slot_info[slot].link_buf_size + DVB_RINGBUFFER_PKTHDRSIZE)) { status = -EAGAIN; @@ -680,14 +674,11 @@ static int dvb_ca_en50221_read_data(struct dvb_ca_private *ca, int slot, u8 * eb /* OK, add it to the receive buffer, or copy into external buffer if supplied */ if (ebuf == NULL) { - down_read(&ca->slot_info[slot].sem); if (ca->slot_info[slot].rx_buffer.data == NULL) { - up_read(&ca->slot_info[slot].sem); status = -EIO; goto exit; } dvb_ringbuffer_pkt_write(&ca->slot_info[slot].rx_buffer, buf, bytes_read); - up_read(&ca->slot_info[slot].sem); } else { memcpy(ebuf, buf, bytes_read); } @@ -802,12 +793,8 @@ static int dvb_ca_en50221_slot_shutdown(struct dvb_ca_private *ca, int slot) { dprintk("%s\n", __FUNCTION__); - down_write(&ca->slot_info[slot].sem); ca->pub->slot_shutdown(ca->pub, slot); ca->slot_info[slot].slot_state = DVB_CA_SLOTSTATE_NONE; - vfree(ca->slot_info[slot].rx_buffer.data); - ca->slot_info[slot].rx_buffer.data = NULL; - up_write(&ca->slot_info[slot].sem); /* need to wake up all processes to check if they're now trying to write to a defunct CAM */ @@ -893,7 +880,7 @@ void dvb_ca_en50221_frda_irq(struct dvb_ca_en50221 *pubca, int slot) case DVB_CA_SLOTSTATE_RUNNING: if (ca->open) - dvb_ca_en50221_read_data(ca, slot, NULL, 0); + dvb_ca_en50221_thread_wakeup(ca); break; } } @@ -1127,16 +1114,16 @@ static int dvb_ca_en50221_thread(void *data) break; } - rxbuf = vmalloc(RX_BUFFER_SIZE); - if (rxbuf == NULL) { - printk("dvb_ca adapter %d: Unable to allocate CAM rx buffer :(\n", ca->dvbdev->adapter->num); - ca->slot_info[slot].slot_state = DVB_CA_SLOTSTATE_INVALID; - dvb_ca_en50221_thread_update_delay(ca); - break; + if (ca->slot_info[slot].rx_buffer.data == NULL) { + rxbuf = vmalloc(RX_BUFFER_SIZE); + if (rxbuf == NULL) { + printk("dvb_ca adapter %d: Unable to allocate CAM rx buffer :(\n", ca->dvbdev->adapter->num); + ca->slot_info[slot].slot_state = DVB_CA_SLOTSTATE_INVALID; + dvb_ca_en50221_thread_update_delay(ca); + break; + } + dvb_ringbuffer_init(&ca->slot_info[slot].rx_buffer, rxbuf, RX_BUFFER_SIZE); } - down_write(&ca->slot_info[slot].sem); - dvb_ringbuffer_init(&ca->slot_info[slot].rx_buffer, rxbuf, RX_BUFFER_SIZE); - up_write(&ca->slot_info[slot].sem); ca->pub->slot_ts_enable(ca->pub, slot); ca->slot_info[slot].slot_state = DVB_CA_SLOTSTATE_RUNNING; @@ -1148,11 +1135,7 @@ static int dvb_ca_en50221_thread(void *data) if (!ca->open) continue; - // no need to poll if the CAM supports IRQs - if (ca->slot_info[slot].da_irq_supported) - break; - - // poll mode + // poll slots for data pktcount = 0; while ((status = dvb_ca_en50221_read_data(ca, slot, NULL, 0)) > 0) { if (!ca->open) @@ -1367,12 +1350,13 @@ exit: /** * Condition for waking up in dvb_ca_en50221_io_read_condition */ -static int dvb_ca_en50221_io_read_condition(struct dvb_ca_private *ca, int *result, int *_slot) +static int dvb_ca_en50221_io_read_condition(struct dvb_ca_private *ca, + int *result, int *_slot) { int slot; int slot_count = 0; int idx; - int fraglen; + size_t fraglen; int connection_id = -1; int found = 0; u8 hdr[2]; @@ -1382,10 +1366,7 @@ static int dvb_ca_en50221_io_read_condition(struct dvb_ca_private *ca, int *resu if (ca->slot_info[slot].slot_state != DVB_CA_SLOTSTATE_RUNNING) goto nextslot; - down_read(&ca->slot_info[slot].sem); - if (ca->slot_info[slot].rx_buffer.data == NULL) { - up_read(&ca->slot_info[slot].sem); return 0; } @@ -1403,10 +1384,7 @@ static int dvb_ca_en50221_io_read_condition(struct dvb_ca_private *ca, int *resu idx = dvb_ringbuffer_pkt_next(&ca->slot_info[slot].rx_buffer, idx, &fraglen); } - if (!found) - up_read(&ca->slot_info[slot].sem); - - nextslot: +nextslot: slot = (slot + 1) % ca->slot_count; slot_count++; } @@ -1511,8 +1489,7 @@ static ssize_t dvb_ca_en50221_io_read(struct file *file, char __user * buf, goto exit; status = pktlen; - exit: - up_read(&ca->slot_info[slot].sem); +exit: return status; } @@ -1544,11 +1521,11 @@ static int dvb_ca_en50221_io_open(struct inode *inode, struct file *file) for (i = 0; i < ca->slot_count; i++) { if (ca->slot_info[i].slot_state == DVB_CA_SLOTSTATE_RUNNING) { - down_write(&ca->slot_info[i].sem); if (ca->slot_info[i].rx_buffer.data != NULL) { + /* it is safe to call this here without locks because + * ca->open == 0. Data is not read in this case */ dvb_ringbuffer_flush(&ca->slot_info[i].rx_buffer); } - up_write(&ca->slot_info[i].sem); } } @@ -1607,7 +1584,6 @@ static unsigned int dvb_ca_en50221_io_poll(struct file *file, poll_table * wait) dprintk("%s\n", __FUNCTION__); if (dvb_ca_en50221_io_read_condition(ca, &result, &slot) == 1) { - up_read(&ca->slot_info[slot].sem); mask |= POLLIN; } @@ -1619,7 +1595,6 @@ static unsigned int dvb_ca_en50221_io_poll(struct file *file, poll_table * wait) poll_wait(file, &ca->wait_queue, wait); if (dvb_ca_en50221_io_read_condition(ca, &result, &slot) == 1) { - up_read(&ca->slot_info[slot].sem); mask |= POLLIN; } @@ -1709,7 +1684,6 @@ int dvb_ca_en50221_init(struct dvb_adapter *dvb_adapter, ca->slot_info[i].slot_state = DVB_CA_SLOTSTATE_NONE; atomic_set(&ca->slot_info[i].camchange_count, 0); ca->slot_info[i].camchange_type = DVB_CA_EN50221_CAMCHANGE_REMOVED; - init_rwsem(&ca->slot_info[i].sem); } if (signal_pending(current)) { @@ -1729,7 +1703,7 @@ int dvb_ca_en50221_init(struct dvb_adapter *dvb_adapter, ca->thread_pid = ret; return 0; - error: +error: if (ca != NULL) { if (ca->dvbdev != NULL) dvb_unregister_device(ca->dvbdev); @@ -1771,6 +1745,9 @@ void dvb_ca_en50221_release(struct dvb_ca_en50221 *pubca) for (i = 0; i < ca->slot_count; i++) { dvb_ca_en50221_slot_shutdown(ca, i); + if (ca->slot_info[i].rx_buffer.data != NULL) { + vfree(ca->slot_info[i].rx_buffer.data); + } } kfree(ca->slot_info); dvb_unregister_device(ca->dvbdev);